Untitled

Annual Report 2006 Jahresforschungsbericht 2006

Berichte des IGB Heft 24/2007 Leibniz-Institut für Gewässerökologie und Binnenfischerei Leibniz-Institute of Freshwater Ecology and Inland Fisheries im Forschungsverbund Berlin e.V.

Annual Report 2006 Jahresforschungsbericht 2006 Herausgeber Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB) im Forschungsverbund Berlin e. V. Müggelseedamm 310, 12587 Berlin Direktor (kommissarisch) Prof. Dr. Gunnar Nützmann Gestaltung Antje Herrmann, Götz Greiner (Weimar) Druck ebert-druck + werbung Berlin ISSN Nr. 1432-508X © 2007 IGB

Content Inhalt

Preface Vorwort 1

The IGB – Structure and Services

12

Das IGB – Struktur und Service 1.1

Structure

12

Struktur 1.2

Administration

14

Institutsleitung 1.3

Scientific Advisory Board

15

Wissenschaftlicher Beirat 1.4

Staff

18

Mitarbeiter 1.5

Works Committee, Ombudsman and Equal Opportunity Commissioner

21

Betriebsrat, Ombudsmann und Gleichstellungsbeauftragte 1.6

Research Services

22

Service

2

Research Program 2005-2007

27

FE-Programm 2005-2007

3

Research Reports – Selected papers

31

Forschungsberichte – Ausgewählte Publikationen 3.1

Research Topic 1 Forschungsschwerpunkt 1

31

Environmental signalling Umweltbedingte chemische Kommunikation 3.1.1

Environmental pollution by bisphenol A: sources and fate in the Elbe basins and biological effects Umweltverschmutzung durch Bisphenol A: Einträge und Stoffverhalten im Elbe-Einzugsgebiet sowie biologische Wirkungen JAGNYTSCH , O., KRÜGER , A., O PITZ , R., LUTZ , I., B EHRENDT, H., KLOAS , W.

33

3.2

Research Topic 2 Forschungsschwerpunkt 2

43

Processes at interfaces Prozesse an Grenzflächen 3.2.1

Reconstruction of pristine morphology, flow, nutrient

45

conditions and submerged vegetation of lowland River Spree (Germany) from palaeomeanders Rekonstruktion der Referenzbedingungen der Unteren Spree hinsichtlich Morphologie, Abfluss, Nährstoffkonzentrationen und Unterwasservegetation aus Paläomäandern HILT, S., S CHÖNFELDER , I., RUDNICKA, A., CARLS , R., N IKOLAEVICH, N., S UKHODOLOV, A., E NGELHARDT , C. 3.2.2

Infiltration of surface water into ground-water

55

under transient pressure gradients Infiltration von Oberflächenwasser in den Grundwasserleiter bei instationären Druckgradienten W IESE , B., N ÜTZMANN ,G.. 3.2.3

Modelling dissolved oxygen dynamics in ice-covered

65

shallow lakes Modellierung des dynamischen Sauerstoffverbrauchs in zugefrorenen Flachseen G OLOSOV, S., K IRILLIN, G..

3.3

Research Topic 3 Forschungsschwerpunkt 3

75

Adaptation, plasticity, and dynamics of communities Adaptation, Plastizität und Dynamik von Biozönosen 3.3.1

Detection and phylogenetic characterization of

77

polyphosphate accumulating bacteria in lake sediments Nachweis und phylogenetische Charakterisierung von Polyphosphat-akkumulierenden Bakterien in Seesedimenten G LOESS , S., HUPFER , M., R ATERING, S., G ROSSART, H.-P.. 3.3.2

Depth distribution of abundant benthic invertebrates in Lake Stechlin Tiefenverteilung von häufigen benthischen Wirbellosen im Stechlinsee HELLAND, I.P., B RAUNS , M., F REYHOF ,J.

89

3.4

Research Topic 4 Forschungsschwerpunkt 4

97

Sustainable management of aquatic ecosystems Nachhaltiges Gewässermanagement 3.4.1

Do littoral habitats with high structural complexity mitigate

99

the impact of ship-induced waves on benthic invertebrates? Reduzieren literorale Habitate mit hoher struktureller Komplexität die Auswirkungen schiffsinduzierten Wellenschlags auf benthische Wirbellose? G ARCIA , X.-F., G ABEL , F., H OCHMUTH , H., B RAUNS , M., S UKHODOLOV, A., P USCH , M.. 3.4.2

Integrated protection of surface waters

109

Integrierter Gewässerschutz von Binnengewässern K OSCHEL , R., B EHRENDT, H., HUPFER , M.. 3.4.3

Dissolved organic matter (DOM) modulates the cadmium

121

accumulation in zebrafish (Danio rerio) embryos Huminstoffe beeinflussen die Cadmium-Akkumulation in Zebrabärblingsembryonen (Danio rerio) M EINELT, T., B URNISON, B. K., P LAYLE , R., P IETROCK , M., W IENKE , A., S TEINBERG , C.E.W. 3.4.4

Towards improved management of infection in

131

aquaculture: strategies arising from the host-parasite interactions in rainbow trout Oncorhynchus mykiss and the pathogenic flagellate Spironucleus salmonis Wege zu einem verbesserten Management von Infektionskrankheiten in der Aquakultur: Strategien basierend auf der Wirt-Parasit Interaktion zwischen der Regenbogenforelle Oncorhynchus mykiss und dem pathogenen Flagellaten Spironucleus salmonis P OYNTON, S.L., S AGHARI F ARD, M.R., B LEISS , W., J ØRGENSEN , A., W EISHEIT, C., M EINELT , T., RENNERT, B., C HENG , J., K IRSCHBAUM , F., KNOPF , K. 3.4.5

Growth performance and body composition of carp (Cyprinus carpio) fed diets containing housefly maggot meal (magmeal) Wachstum und Körperzusammensetzung von Karpfen (Cyprinus carpio) denen Futtermittel mit Fliegenmadenmehl verabreicht wurden O GUNJI , J.O., S UTTER , D., RENNERT, B., KLOAS , W., S CHULZ , C.

140

4

Statistics Statistik

149

4.1

Peer-reviewed papers

151

Artikel in referierten Zeitschriften 4.2

Non-reviewed papers, books, book chapters and reports

161

Artikel in nichtreferierten Zeitschriften, Bücher, Buchbeiträge und Berichte 4.3

Degrees

168

Abschlüsse 4.3.1

Bachelor and Master Theses

168

Bachelor- und Diplomarbeiten 4.3.2

PhD Theses

169

Doktorarbeiten 4.3.3

Pre-Professional Theses

170

Habilitationen 4.4

Lectures at universities

171

Vorlesungen an Universitäten 4.5

Memberships in Scientific and Editorial Boards

174

Verantwortliche Positionen in Fachgesellschaften oder Gremien 4.6

Projects and Grants

176

Projekte und Stipendien 4.7

Summary

184

Gesamtübersicht 4.8

List of published IGB reports Liste der bisher veröffentlichten Berichte des IGB

185

Preface

Vorwort

Freshwater is the earth’s most valuable natural resource. The main challenge of our century is to reconcile the needs for water in human societies with the requirements for healthy freshwater ecosystems. Management of these resources must rely upon the best available scientific knowledge including the factors controlling the structure, function, quality, and quantity of freshwaters. Based on these premises the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB, established on 1 January 1992) is engaged in studies comprizing the functioning, diversity, and management of freshwater ecosystems based on multidisciplinary research activities. Research areas typically located in NE Germany and adjoining regions include: interactions between surface and groundwater, deep stratified and shallow lakes, shallow lakes interconnected with lowland rivers, river stretches and ponds. The state Brandenburg e.g., is characterized by more than 3.000 lakes of various sizes and characteristics indicating the need for substantial research. The IGB’s national and international reputation in the field of aquatic ecology has grown steadily and the Institute - comprising approximately 150 staff members and about 50 PhD-students - houses now many prestigious hydrological, limnological, and fish ecological research groups. During the year 2006 the completion of the new aquarium hall – the inauguration ceremony took place on the 4th of October – marked a further step towards the development of a modern research Institute. The facilities comprise several independent re-circulatory systems and facilities for various experimental research activities; these potentials which will further tighten the cooperation with institutions at the national and international level. At the end of 2006 the candidates for the open post of the director of the Institute have presented their ideas on the scientific development of the IGB. The final decision concerning the open post will be taken in 2007 and this new personal situation will certainly also have impact on the future research program of the IGB. The scientific activities of our Institute are summarized in annual research reports. We have selected 11 topics from our research programme comprising four key areas: 1) environmental signalling, 2) processes at aquatic interfaces, 3) adaptation, plasticity, and dynamics of aquatic communities and 4) sustainable management of aquatic ecosystems. From 1997 to 2005 the annual reports were prepared by the departments of the IGB. The report for 2006 for the first time has been managed in part by the department IV (Dr. Wolter), and by the head of the library, Mrs. Grosse. We would like to thank them for their effort and all colleagues for the work accomplished in 2006.

© IGB 2007

Frank Kirschbaum

Gunnar Nützmann

Department of Biology and Ecology of Fishes

Director (in charge)

9

Improved experimental facilities – the new aquaria hall

After two years of construction work IGB’s new aquaria hall was solemnly inaugurated on October 04, 2006. The architecturally strict and functional building is situated at Müggelseedamm 310. On two floors it has a main usable space of more than 1000 m², climate chambers, labs, a dissection lab and a modern seminar room for lectures and conferences. The largest basins have a volume of 36000 l each, and therein swim among others mature sturgeons. Other aquaria and circulation systems contain pike perch, carp, roach, eel, zebra fish and striped mullets used in several distinct experiments and projects. The total costs of 2.46 billion Euros have been financed to equal parts (985,000 € each) by the Berlinean Senate and the Federal Ministry of Education and Research as well as by the European Union (EFRE 460,000 €). On the other hand, the new improved experimental facilities enabled the raising of 10 projects with a total budget of 2.43 billion Euros and 17.5 temporary positions since 2005.

10

The main aquaria hall in the basement has nine separate, closed circulation systems used for harvesting the sturgeon breeding stock, as well as for various experiments with eels (previous page), carp, tilapia and other fish species.

Photos IGB/Ralf Günter Each circulation system has its own prufication unit, with mechanical and biological treatment. In addition ozonisation and UV-desinfection are possible.

© IGB 2007

11

12

Administration Director

Rivers

Prof. Dr. N. Walz

Prof. Dr. R. Koschel

Shallow Lakes

Prof. Dr. G. Nützmann

Stratified Lakes

Limnology of

and Lowland

Limnology of

Department II

Department I

Ecohydrology

Prof. Dr. F. Kirschbaum

Fishes

Ecology of

Biology and

Department IV

Prof. Dr. W. Kloas

Inland Fisheries

Department V

Dr. J. Gelbrecht

Laboratory

Chemical

Central

G. Krätsch

M. Sieber

J. Hochschild

Department III

Administration Team Technical Team

Dr. F. Fabich

Library

Prof. Dr. G. Nützmann

Director (in charge)

Information Technology Team

Prof. Dr. H. E. Segner (chair)

Scientific Advisory Committee

Board of Directors of the Research Association Berlin e. V.

Structure

Board of Trustees

General Meeting

1.1

Member of the Research Association Berlin e.V.

Leibniz-Institute of Freshwater Ecology and Inland Fisheries

1 The IGB – Structure and Services Das IGB – Struktur und Service

Struktur

Further Information Weitere Informationen

Supporting Organisations

Federal Government (BMBF) and Country of Berlin each 50% Organisation

The institute is a member of the Research Association Berlin e.V. (see structure of IGB) Staff (from 31.12.2006)

39 24 11 26 68 5

Scientists (internally funded) Scientists (project or grant funded) Ph.D. students (internally funded) Ph.D. students (project or grant funded) Technical and administrative staff (internally funded) Technical staff (project or grant funded)

Annual budget

8,500,000 € Publications

The scientific results are continuously published in national and international journals. Lists of all publications in which staff members are involved are published regularly in the “Berichte des IGB” / Annual Reports Journals

„International Review of Hydrobiology” (ISSN 1434-2944) „Limnologica” (ISSN 0075-9511) „Berichte des IGB“ (ISSN 1432-508X)

© IGB 2007

13

1.2 Administration

Institutsleitung

Director (in charge) Prof. Dr. Gunnar Nützmann Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 661 fax: +49 (0) 30 - 64 181 663 e-mail: [email protected]

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Head of Administration G. Krätsch Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 603 fax: +49 (0) 30 - 64 181 600 e-mail: [email protected]

Secretary B. Spieler Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 602 fax: +49 (0) 30 - 64 181 600 e-mail: [email protected]

Head of Department I Ecohydrology Prof. Dr. G. Nützmann Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 661 fax: +49 (0) 30 - 64 181 663 e-mail: [email protected]

Head of Department II Limnology of Shallow Lakes and Lowland Rivers Prof. Dr. N. Walz Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 - 64 181 680 fax: +49 (0) 30 - 64 181 682 e-mail: [email protected]

Head of Department III Limnology of Stratified Lakes Prof. Dr. R. Koschel Alte Fischerhütte 2 16775 Stechlin-Neuglobsow phone: +49 (0) 330 82 - 69 90 fax: +49 (0) 330 82 - 69 917 e-mail: [email protected]

Head of Department IV Biology and Ecology of Fishes Prof. Dr. F. Kirschbaum Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 610 fax: +49 (0) 30 - 64 181 750 e-mail: [email protected]

Head of Department V Inland Fisheries Prof. Dr. W. Kloas Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 - 64 181 630 fax: +49 (0) 30 - 64 181 799 e-mail: [email protected]

Head of Central Chemical Laboratory Dr. J. Gelbrecht Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 - 64 181 730 fax: +49 (0) 30 - 64 181 682 e-mail: [email protected]

1.3 Scientific Advisory Committee Wissenschaftlicher Beirat

Prof. Dr. H. E. Segner address:

phone: fax: e-mail: member since:

Prof. Dr. H. Rosenthal address: phone: fax: e-mail: member since:

Prof. Dr. E. van Donk address:

phone: fax: e-mail: member since:

Prof. Dr. W. Endlicher address:

phone: fax: e-mail: member since:

© IGB 2007

Chair of Advisory Committee Zentrum für Fisch- und Wildtiermedizin am Institut für Tierpathologie Universität Bern Länggass Straße 122 CH-3012 Bern +41 (0) 31 – 63 12 441 +41 (0) 31 – 63 12 611 [email protected] 01.01.2002

Deputy Chair of Advisory Committee Schöfferstraße 48 21629 Neu Wulmsdorf +49 (0) 40 – 70 06 514 +49 (0) 40 – 67 01 02 676 [email protected] 01.12.2000

Department of Food Web Studies Institute of Ecology Rijksstraatweg 6 3631 Nieuwersluis The Netherlands +31 (0) 294 – 239 353 +31 (0) 294 – 232 224 [email protected] 01.12.2004

Humboldt-Universität zu Berlin, Mathem.-Naturwissensch. Fakultät II Geographisches Institut Unter den Linden 6 Sitz: Rudower Chaussee 16 10099 Berlin +49 (0) 30 – 20 93 68 08 +49 (0) 30 – 20 93 68 44 [email protected] 01.01.2003

15

Dr. K. Fent address:

phone: fax: e-mail: member:

Prof. Dr. F. Frimmel address:

phone: fax: e-mail: member since:

Prof. Dr. U. Grünewald address:

phone: fax: e-mail: member since:

Prof. Dr. E. A. Huisman address:

phone: e-mail: member:

16

Institut für Umwelttechnik Fachhochschule beider Basel St. Jakobs-Strasse 84 CH-4132 Muttenz +41-(0)61-467 45 05 +41-(0)61-467 42 90 [email protected] [email protected] 01.12.1998 - 30.11.2006

Universität Karlsruhe (TH), Engler-Bunte-Institut, Lehrstuhl für Wasserchemie Richard-Willstätter-Allee 5 76131 Karlsruhe +49 (0) 721 – 60 82 581 +49 (0) 721 – 69 91 54 [email protected] 01.12.2000

Brandenburgische Technische Universität Cottbus, Fakultät Umweltwissenschaften und Verfahrenstechnik Postfach 10 13 44 03013 Cottbus +49 (0) 355 69 42 33 +49 (0) 355 69 42 35 [email protected] 01.12.2004

Institute of Animal Sciences Wageningen c/o Koningsweg 6 NL-66 55 AC Puiflijk +31 (0) 487 – 51 56 79 [email protected] 01.12.2000 - 06.10.2006

Prof. Dr. W. Lampert address:

phone: fax: e-mail: member:

Prof. Dr. S. Peiffer address:

phone: fax: e-mail: member since:

Prof. Dr. K.-J. Peters address:

phone: fax: e-mail: member since:

Prof. Dr. Th. Weisse address:

phone: fax: e-mail: member since:

© IGB 2007

Max-Planck-Institut für Limnologie Plön Postfach 165 24302 Plön +49 (0) 45 22 – 76 32 70 +49 (0) 45 22 – 76 33 10 [email protected] 01.12.1998 - 30.11.2006

Universität Bayreuth Lehrstuhl für Hydrologie 95440 Bayreuth +49 (0) 921 55 22 51 +49 (0) 921 55 23 66 [email protected] 01.12.2004

Humboldt-Universität zu Berlin Institut für Nutztierwissenschaften Phillippstr. 13 10115 Berlin +49 (0) 30 – 20 93 63 63 oder -62 +49 (0) 30 – 20 93 63 70 [email protected] 01.01.2003

Institut für Limnologie Österreichische Akademie der Wissenschaften Mondseestr. 9 A-5310 Mondsee +43 (0) 6232 - 3125 +43 (0) 6232 - 3578 [email protected] 01.12.2004

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1.4 Staff (December 31, 2006) Mitarbeiter (31. Dezember 2006)

Director Internally funded Nützmann, Gunnar Sakowsky, Alexandra Spieler, Brigitte

Administration and Technical Team Internally funded Albrecht, Gerda Bednarz, Stefan Gaertner, Hartmut Gürtler, Frido Krätsch, Gisela Schäricke, Kerstin Schmidt, Mathias

Information Technology Team Internally funded Henke, Vera Hochschild, Johannes Kalberg, Christian Voß, Astrid

Library Internally funded Große, Christine (since 09/2006) Hentschel, Ute Sieber, Magdalena (till 07/2006)

Central Chemical Laboratory

18

Internally funded

Project or grant funded

Exner, Hans-Jürgen Gelbrecht, Jörg Guder, Sylvia Herzog, Christiane Hupfer, Michael Krüger, Angela Lüder, Antje Rossoll, Thomas Schütze, Bernd Zwirnmann, Elke

Kleeberg, Andreas Żak, Dominik

Ecohydrology (Dept. I) Internally funded

Project or grant funded

Brüggemann, Rainer Bungartz, Heinz Engelhardt, Christof Friedrich, Hans-Jörg Kobisch, Barbara Lewandowski, Jörg Nützmann, Gunnar Schwamm, Dagmar Siegert, Grit Sukhodolov, Alexander

Ginzel, Gerhard Golosov, Sergey Hamann, Enrico Horner, Christoph Kirillin, Georgiy Molkenthin, Christian Schnauder, Ingo Suhodolova, Tatiana

Limnology of Shallow Lakes and Lowland Rivers (Dept. II) Internally funded

Project or grant funded

Adrian, Rita Behrendt, Horst Graupe, Marianne Hintze, Thomas Hölzel, Reinhard Klockau-Raddatz, Sylvia Köhler, Jan Kozerski, Hans-Peter Lehmann, Katrin Meinck, Barbara Newen, Ursula Pusch, Martin Täuscher, Helgard Walz, Norbert Winkler, Hanna

Bauer, Nadine Brauns, Mario Carl, Peter Gericke, Andreas Hilt, Sabine Hirt, Ulrike Hofmann, Jürgen Huber, Veronika Leszinski, Marc Mischke, Ute Opitz, Dieter Strube, Torsten Venohr, Markus Wagner, Carola Wilhelm, Susann (till 10/2006)

Limnology of Stratified Lakes (Dept. III)

© IGB 2007

Internally funded

Project or grant funded

Allgaier, Martin Beyer, Ute Casper, Peter Dalchow, Johanna Degebrodt, Monika Degebrodt, Roman Glöß, Stefanie Grossart, Hans-Peter Kasprzak, Carola Kasprzak, Peter Koschel, Rainer Krienitz, Lothar Mach, Elke Mallok, Uta Papke, Monika Pommerening, Eleonore Roßberg, Reingard Sachtleben, Michael Scheffler, Adelheid Schulz, Marina Tesch, Edith Wiedner, Claudia

Dziallas, Claudia Eixler, Sebastian Hutalle, Kristine Michelle L. Jander, Jörn Koppe, Cathleen Rychla, Anna Sergelen, Gongor Stüken, Anke Wauer, Gerlinde

19

Biology and Ecology of Fishes (Dept. IV) Internally funded

Project or grant funded

Arlinghaus, Robert Daedlow, Katrin Faller, Markus Fischer, Leonore Freyhof, Jörg Helms, Christian Kirschbaum, Frank Kuntze, Karena Löschau, Peter Mehner, Thomas Ohlberger, Jan Osman, Alaa Gad El-Karim Mahmoud Pohlmann, Kirsten Rohde, Titus Simon, Marcel Staaks, Georg Stelbrink, Björn Türck, Alexander Uusi-Heikkilä, Silva Wolter, Christian Zwadlo, Henrik

Baganz, Daniela Beardmore, Alan Benedict Dorow, Malte Garcia, Xavier-Francois Geßner, Jörn Helland, Palm Ingeborg Huckstorf, Volker Lewin, Wolf-Christian Würtz, Sven-Holger

Inland Fisheries (Dept. V)

20

Internally funded

Project or grant funded

Ballegooy, Christoph van Cuppok, Ingo Hübner, Bettina Kersten, Petra Kloas, Werner Knopf, Klaus Kohlmann, Klaus Kunow, Mathias Lorenz, Claudia Lutz, Ilka Meinelt, Thomas Neumann, Nadja Nimptsch, Jorge Pflugmacher, Stephan Pietsch, Constanze Rennert, Bernhard Schumacher, Wibke Stüber, Angelika Tillack, Antje Urbatzka, Ralph Vassilakaki, Maria Viehmann, Viola Wiedemann, Caterina Wiegand, Claudia

Ballot, Andreas Contardo Jara, Valeska Fard, Mohammad Reza Saghari Frank, Sabrina Grigutyte, Reda Jagnytsch, Oana Kamara, Sheku Menzel, Ralph Opitz, Robert Peuthert, Anja Rienau, Stefanie Trubiroha, Achim

1.5 Works Committee, Ombudsman and Equal Opportunity Commissioner Betriebsrat, Ombudsmann und Gleichstellungsbeauftragte

Chairman E. Zwirnmann Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 735 e-mail: [email protected]

P. Casper Alte Fischerhütte 2 16775 Stechlin-Neuglobsow phone: +49 (0) 33 082 – 69 929 e-mail: [email protected]

C. Engelhardt Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 664 e-mail: [email protected]

M. Kunow Müggelseedamm 310 12587 Berlin phone: +49 (0) 30 – 64 181 702 e-mail: [email protected]

Th. Hintze Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 689 e-mail: [email protected]

J. Dalchow Alte Fischerhütte 2 16775 Neuglobsow phone: +49 (0) 33 082 – 69 916 e-mail: [email protected]

K. Wagner Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 693 e-mail: [email protected]

Ombudsman “Safeguarding good scientific practice”

M. Hupfer Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 605 e-mail: [email protected]

Equal Opportunity Commissioner

A. Krüger Müggelseedamm 301 12587 Berlin phone: +49 (0) 30 – 64 181 735 e-mail: [email protected]

© IGB 2007

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H OCHSCHILD , J.

1.6 Research Services

Service

1.6.1 Information Technology Team Informatik und Rechentechnik

The Information Technology Team (ITT) of the IGB provides computer, software and net equipment for all research departments, management offices, and the library in our institute. That means to design, to set up and to maintain the intra-network, file and application services and, last but not least, the connection to the internet (e-mail, www, ftp, vpn, etc). The largest part of ITT’s task spectrum is the maintenance of the workplace computer pool (Intel PCs, mostly running MS-Windows, W2K), which consists of approximately 500 PCs, including 100 computers for special jobs in the laboratories and 80 notebooks. In addition to the hardware and operating system oriented activities, ITT has also to purchase, install, set up and evaluate standard and special software. In a lot of cases ITT is even developing new software solutions, e.g. a measurement database, interface software for measuring devices, and a cgi access to the IGB literature catalogue for the IGB website. The next, just as important, part of ITT’s area of responsibility is the administration and maintenance of the big fileservers and the pool of special servers. A very important field to do it is the safeguarding of the data stored on the servers, against any loss or destruction. For this purpose ITT developed a novel system with a special magnetic tape library, so that data can be restored up to three month backdated. For higher security and good availability of IGB’s data pool, in 2004 began the use of Server-RAIDsystems. In the following years the use of RAID-systems was powerful expanded. Beginning in the October 2006 in the IGB was installed a Wireless Local Area Network. The scientists and students have now easy accesses to the internet and the common IGB network with their notebooks on any places in the IGB buildings. For the other services, such as email, databases, etc. the server pool still containing several HP, IBM RS6000, SUN, Compaq Alpha, and Intel/Linux servers. Some SUN and Intel workstations perform special jobs for simulations and special numerical calculations. ITT also maintains some web servers e.g. "www.igb-berlin.de" or “www.adaptfish.igb-berlin.de” or “www.flake.igb-berlin.de” and supports the activities of the research departments in developing their own homepages, and guarantees the web presentation of the IGB, which is of great importance for the publicity of the institute. With the ever growing expansion of the internet, we are permanently faced with different security problems in the IGB network. By setting up and maintaining a firewall router, we spend a great deal of our resources on the protection of the systems from actions of foreign hackers.

22

The IGB has its own internet domain, named "igb-berlin.de". All scientists, staff and guest researchers and the technical staff can use the internet and e-mail services, web browsers and FTP-tools directly from their workplaces. Incoming and outgoing e-mails are collected in a common mail host, where viruses and spam mails are filtered out, so that only checked mails are distributed to the recipients. Infected mails are returned to the senders. In order to print documents and graphics, members of the institute have access to more than 80 greyscale and colour laser printers. Posters can be designed and printed with equipment consisting of a graphic workstation and a DIN-A0-HP-Posterjet 5000. Other periphal devices include scanners, slide exposers, digitalising tablets, projectors and notebooks. The IGB administration is working with a SAP/R3 database. Seven PCs are connected by X21/ISDN wires with a central SAP system. The most used software applications in the IGB are MS-Office, CorelDraw 12, Havard-Graphics 4.0, SigmaPlot, Origin, Mathlab, ModelMaker, SPSS, SAS, AVS, Esri’s GIS “ArcInfo/ArcView”, Reference Manager, BISLOK and the programming languages C/C++, Java, Fortran, Simula and Pascal. In 2006 for the first time was provided a “Windows 2003 Server” configured as a terminal server to make available comprehensive statistical and other special software to the workplace pcs. The freeware SAMBA, running on the UNIX-machines, is used to resolve the network file services.

© IGB 2007

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G ROSSE , C H .

1.6.2 Library Bibliothek General information

The library is a special scientific library providing the central information supply for the Leibniz-Institute of Freshwater Ecology and Inland Fisheries. The information transfer is determined by the research profile of the institute, and subject specialisations in limnology, ecohydrology, geohydrodynamics, fishery sciences and water management. While the library mainly serves to support the employees of the IGB with literature, visitors and students can also use the library, under slightly restricted conditions. Tasks and services acquisitions (literature selection and literature procurement by -

purchase, exchanges and gifts) bibliographical search through international and external data bases documentation of IGB publications literature supply from other facilities via inter-library loan publications: list of periodicals, new acquisitions list supply of books

Library software BIS-LOK Version 5, Alephino 3.0 (change 09/2006) Search possibilities

In the library: alphabetical and classified catalogues (accessioning of the bookstock before 2002) OPAC =Online Public Access Catalogue (proof of all bookstock) ASFA = Aquatic Science and Fisheries Abstracts (for 1978 to 2002, CD-ROM) Online: ISI/JCR = Institute for Scientific Information/Journal Citation Reports ISI/WoS = Institute for Scientific Information/Web of Sciences Use -

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open access library reference collection – loan to employees

Technical provision 18 reading seats -

3 PC work stations with internet access 2 microfilm readers photocopier

Users employees of the institute, guests researchers, students and other -

external users Opening hours for employees and guests during normal working hours at the -

institute external users according to agreement by telephone

Staff

Magdalena Sieber (till 08/2006) Christine Große (since 09/2006) Head of Library phone: 030/64 181 655 fax: 030/64 181 676 e-mail: [email protected] [email protected]

© IGB 2007

Ute Hentschel Librarian phone: 030/64 181 656 fax: 030/64 181 676 e-mail: [email protected]

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P OYNTON , S. L.

1.6.3 Scientific Communications Skills: Advanced Course Wissenschaftliche Kommunikation: Kurse für Fortgeschrittene

The commitment of IGB to supporting the professional development of its members was shown again in summer 2006, when scientists in Berlin had the opportunity to participate in a course entitled “Scientific Communication Skills: Advanced Level”. The intensive course, taught in English, focussed on the strategies and skills needed to make the transition from good to excellent scientific communications. The course began with a brief review of the history of scientific communication, and recognised that over the millennia, many different languages have been dominant, including Latin, Greek, Chinese, German, French, and currently English. Special consideration was then given to some stylistic differences in writing styles between German and English, and avoidance of common errors in usage. When examining the art of scientific writing, participants learned how to craft effective – audience specific –titles, how to write persuasive introductions and discussions, the importance of strong opening and closing sentences and paragraphs, and how to write smoothly flowing elegant texts. By comprehensive class critique of published texts, and those currently being written by the participants, the class learned to recognise strong and weak writing styles, and began to develop skills for editing texts for content, form and style. In addressing spoken communication skills, emphasis was placed not only on the content of a presentation, but also on the crucial importance of effective delivery. Participants had many opportunities to practice giving presentations on different topics, and in a variety of formats. In each class, feedback was given on correct vocabulary, grammar and pronunciation. For this advanced course, attention was also drawn to broad aspects of professional development, such as networking, leadership, and active and effective participation in conferences. The participants brought to the course, a diversity of research expertise, levels of experience, and language skills, which greatly enriched the learning environment. The small class size ensured intense interaction, individual attention, and many opportunities to speak English. The course was taught by Dr. Sarah Poynton, an experienced research scientist and international educator, who has directed and taught the Scientific Communications Skills program in IGB for nearly 10 years. Classes were competently supported by Dr. Poynton’s teaching assistant, Mr. M. Reza Saghari Fard, a Ph.D. student from Department V.

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2 Research Program 2005-2007 FE-Programm 2005-2007

2.1 Focus 1: Environmental signalling Focust 1: Umweltbedingte chemische Kommunikation Co-ordinator: Werner Kloas

The highly evolved sensitivity of signal receptors to exogenous chemical stimuli can make organisms vulnerable to natural compounds and man-made chemicals that mimic specific chemical cues or interfere with receptors. The environmental signalling research programme will focus upon the stimuli emitted by cyanobacterial secondary metabolites, natural biogeochemicals and endocrine disrupters, and will determine their effects on molecular modes of action, organisms and ecosystems. We investigate various aspects of signalling, biotransformation processes, signal pathways via reactive oxygen species (ROS), receptor signal transduction and gene expression, in a range of aquatic organisms from cyanobacteria to vertebrates, thus encompassing multiple compartments of lake ecosystems. The studies emphasize broadening and deepening our understanding of how aquatic organisms perceive and respond to both internal and external signals in order to ensure appropriate changes in their cellular metabolism, energy allocation, growth, development, reproduction and behaviour. Since many effects of environmental signalling are phenomenological, the major research effort will elucidate the corresponding modes of action. The central focus of our research will seek to determine if environmental signalling by natural compounds (cyanobacterial secondary metabolites and humic substances), as well as by natural and man-made endocrine disrupters, have the potential to significantly impact individual organisms and, in turn, also populations. Thus these mechanistic approaches to research will create information for potential risk assessment of aquatic ecosystems.

2.2 Focus 2: Processes at interfaces Focus 2: Prozesse an Grenzflächen Co-ordinators: Gunnar Nützmann, Norbert Walz

In the glacially formed landscape of North-Eastern Germany, nutrients and energy are mutually transformed and transported at the interfaces between groundwater and sediment and between sediment and surface water. This situation raises the question as to how the amount and the velocities of these transformations underlie biological, chemical or physical processes. We will focus on quantifying the exchange processes at these interfaces in order to better understand the underlying mechanisms and to provide a foundation for better modelling.

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In this subject group, we focus on a unique combination of expertise in different disciplines (hydrology, mathematical modelling, water chemistry, macrophyte- plankton-and benthos-ecology) as wellas on the hydrology and biogeochemistry of this landscape. Project 2.1 (Hydrodynamic control of fluxes and biota) is desiqued to study the turbulent currents in rivers and lakes which influence all processes at the interfaces between open water and the biota. In projects 2.2, 2.3 and 2.4 processes occurring at specific interfaces are examined: the exchange of ground and surface water through the sediment (Project 2.2, Connectivity between ground and surface waters), the biogeochemical transformations between sediment and surface water, especially their promotion by biological factors (Project 2.3, Biogeochemical processes in microzones) and the biological exchange between benthic structures and open water that determine the ecological status of shallow waters (Project 2.4, Benthic pelagic coupling and bistability in shallow systems).

2.3 Focus 3: Adaptation, plasticity, and dynamics of communities Focus 3: Adaptation, Plastizität und Dyanmik von Biozönosen Co-ordinator: Rainer Koschel

Research focus 3 will identify ecological and evolutionary based optimisation strategies of speciation and of biodiversity. A better understanding of adaptation, plasticity and dynamics of microorganisms, plankton and fish communities will lay a new theoretical foundation for the sustainable management of aquatic ecosystems. Our research builds upon previous IGB investigations of lowland ecosystems as the lakes Müggelsee, Stechlin and Breiter Luzin and the rivers Spree and Oder. Project 3.1 “Structuring of microbiota by biological interactions” will examine the genotype and chemotype diversity and phenotypic plasticity of bacteria, methanogenic archaea, cyanobacteria and algae. Project 3.2 “Regulation of fish diversity in running waters” is focused on key abiotic factors, life history differentiation and hybridisation of sturgeon species. Project 3.3 “Ecological factors in speciation of fishes” will address differential ecological adaptation and sympatric speciation of cisco species (Coregonus spp.). Project 3.4, directed to “Climate change biology”, is guided by the hypothesis that climate changes induce long-term changes in the phenology of plankton and subsequent pertubations in species interactions.

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2.4 Focus 4: Sustainable management of aquatic ecosystems Focus 4: Nachhaltiges Gewässermanagement Coordinator: Christian Wolter

Research focus 4 was established in 2000 to develop scientifically rigorous approaches for adaptive and sustainable water and ecosystem management strategies in freshwaters. The individual projects are primarily designed to facilitate sustainable use and to expand our knowledge of the structure and functioning of freshwater ecosystems. This approach supports the statutory mission of the IGB, which includes transfer of the results of basic ecologic research into applied science. Our results include the development of in-lake restoration techniques, assessment schemes for biological classifications of lakes and rivers, and a characterization of recreational fisheries as one of the major users of fish stocks. In future, integrative management options will be analysed and evaluated, such as reduction of external nutrient loading combined with in-lake ecological engineering, biodiversity protection and conservation-driven fisheries management, to maximize stakeholder benefits and minimize environmental impacts. The response of stagnant and running freshwater systems to restoration measures will be used as large-scale scientific experiments to improve the ecosystem theory of degraded water systems and to promote the costs-by-cause principle in conservation. In urban areas, the ecological potential of heavily modified water bodies will be assessed to aid in the implementation of the Water Framework Directive (WFD). Beyond 2008 we will attempt to integrate ecological and socio-economic studies to reflect the human dimensions in natural resource management. This work will be done in co-operation with social and economic research institutes and by expanding our own scientific expertise. Research focus 4 comprises the following projects: 4.1 Management of river systems: development of ecological knowledge to support sustainable restoration and management concepts for running waters. 4.2 Ecological engineering and lake ecosystem development: long-term analyses of manipulated and restored, deep, thermally-stratified lakes and drainage basins in Germany’s Baltic Lake District. 4.3 Inland Fisheries: development of sustainable aquaculture strategies to support the improvement of fish culture while minimising environmental impacts. Furthermor, we seek a holistic understanding of the human and biological component of fisheries systems and their management.

© IGB 2007

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30

3 Research Reports – Selected Papers Forschungsberichte – Ausgewählte Publikationen

3.1 Research Topic 1 Forschungsschwerpunkt 1

Environmental signalling Umweltbedingte chemische Kommunikation

© IGB 2007

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32

J AGNYTSCH , O., K RÜGER , A., O PITZ , R., L UTZ , I., B EHRENDT , H., K LOAS , W.

3.1.1 Environmental pollution by bisphenol A: sources and fate in the Elbe basins and biological effects Umweltverschmutzung durch Bisphenol A: Einträge und Stoffverhalten im Elbe-Einzugsgebiet sowie biologische Wirkungen

Key words: bisphenol A, emission, retention, endocrine disruptor, Xenopus laevis, thyroid system, reproductive system Abstract

Households and industrial discharges are the main sources of bisphenol A (BPA), an environmental chemical suspected to cause severe effects on endocrine systems, in surface waters. The emissions are realised by waste water treatment plants (WWTP) and combined sewer systems as well as industrial direct discharges. It was estimated that the total inputs into the river system of Elbe are about 970 kg/a by WWTP, 70 kg/a by sewer systems and 510 by two industrial discharges in the Czech part of Elbe. The retention within the surface waters of Elbe is 790 kg/a or 51%. Xenopus laevis premetamorphic tadpoles at stages 48 and 51 were exposed to different BPA concentrations ranging from 223 ng/L to 223 µg/L to analyse effects on sexual differentiation and thyroid system. BPA caused moderate effects on thyroid system by interference with thyroid receptors but had adverse effects on sexual differentiation disrupting normal gonadal development particularly in males as shown by gross morphological and histological determinations. Zusammenfassung

Haushalte und industrielle Direkteinleiter gehören zu den Haupteinträgern von Bisphenol A (BPA) in die Oberflächengewässer des ElbeEinzugsgebietes. Die Emission erfolgt dabei über kommunale Kläranlagen (WWTP), Gemischtwasserkanalisation sowie industrielle Direkteinleiter. Der Gesamteintrag von BPA über die WWTP beläuft sich auf etwa 970 kg/a, der über die Gemischtwasserkanalisation auf 70 kg/a und etwa 510 kg/a entfallen auf zwei industrielle Direkteinleiter im tschechischen Teil der Elbe. Die Retention innerhalb der Oberflächengewässer der Elbe beträgt 790 kg/a bzw. 51%. Xenopus laevis Kaulquappen im Entwicklungsstadium 48 bzw. 51 wurden mit verschiedenen BPA-Konzentrationen im Bereich von 223 ng/L bis 223 µg/L exponiert, um die Wirkungen von BPA auf die Sexualdifferenzierung und das Schilddrüsensystem zu untersuchen. BPA beeinflußte das Schilddrüsensystem über Interaktionen mit dem Schilddrüsenrezeptor nur moderat, zeigte aber adverse Auswirkungen auf die Sexualdifferenzierung durch Störungen bei der Gonadenentwicklung von männlichen Individuen auf morphologischer und histologischer Ebene.

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3.1.1.1

Introduction

Climate change is recently one of the most important issues in environmental sciences. Many scientific groups are concerned about worldwide temperature and precipitation changes within near future. However, not only rising temperatures and increase of natural disaster are able to modify regions, nutrients, animal or human populations but also environmental pollution in surface water. Since few years especially xenobiotica and recently pharmaceutical compounds are objects of ecotoxicological studies. Xenobiotica contain to the group of “endocrine disruptors” (ED). EDs are compounds which interfere with endocrine systems and disrupt their normal functions within an organism without remarkable toxicity (Colborn et al. 1996, Kloas 2002). Since the 1990`s an increasing pollution of such compounds was noticed for instance in surface waters, agricultural areas, and atmosphere, especially since the analytical methods for detection have been continuously improved. Bisphenol A (BPA) is one of the most common chemicals for production of epoxy resins and polycarbonate plastics (Fig. 1). CH3 HO

C

OH

CH3 Fig. 1: Chemical structure of bisphenol A.

BPA is widely used for all kind of products like computer housings, carpets, upholstery, for car paintings and flame retardants such as tetrabromobisphenol A (TBBA). BPA attracted public attention when it has been generally known that it can leach out of plastic baby bottles or cans and migrate into milk and food (Goodson et al. 2004, Braunrath et al. 2005). Since BPA could be detected in diverse human tissues and environmental samples it is nessessary to analyze its biological effects. Clear evidences exist for feminization caused by BPA in snails, fish, and amphibians (Oehlmann et al. 2005, Yokota et al. 2000, Levy et al. 2004) and many publications have shown effects regarding reproduction but some findings are still controversely discussed (Pickford et al. 2003, Yoshida et al. 2004). To get a better understanding of BPA in a prospective perspective it is necessary to assess the general sources and environmental fate of BPA. Therefore the Elbe River system was used as a model. It is the second-largest river system in Germany and one of the largest in central Europe. The biological effects on thyroid system and reproduction were evaluated by means of an amphibian model, the South African clawed toad Xenopus laevis. 3.1.1.2

Material and Methods Bisphenol A emissions and retention

The Elbe river system has been investigated for BPA emission and retention. Literature and internet were used to collect informations about chemical properties, and usage of BPA as well as to accumulate data about BPA

34

determination of surface water samples. Mean BPA emissions have been calculated by using the MONERIS model (Behrendt et al. 2003). This model considers following 7 different pathways: particle entry via erosion, dissolved entry via avulsion, basis flow, interflow, tile drainage, atmospheric deposition on water surface areas, sealed urban areas, and point source discharges. Based on informations about inflow and outflow of several WWTP BPA retention for WWTP was calculated. The following retention function was used to create a graph which compares observed BPA concentrations measured along the Elbe main stream and calculated BPA concentrations:

C BPA C BPAINPUT

1

1  a º HL 1

HL: Hydraulic loading a= 7.18 BPA determination of water samples of Elbe-river catchment by HPLC

Additional to existing environmental data several water samples within the Elbe catchment and tributaries were collected to determine BPA in surface water. Water samples were taken monthly from Spree, Havel, Havel/Spree as well as from WWTP outflow Münchehofe and Erpe. Samples from Wuhle I, II, and Elbe were taken once. 2000 mL water sample were taken from the middle stream and gross filtrated by using glass fiber filters. Each sample was supplemented by 10 g NaCl and concentrated HCl for acidification. RP18 columns were used to concentrate BPA of 1000 mL water sample volume, followed by eluation with acetone. Eluats were dried and resuspended in 1 mL acetonitrile. BPA determination was done by mean of HPLC. Test Animals

The animals used for the exposure experiments are coming from an animal stock of the Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany. Adult frogs were induced to spawn by injecting human chorionic gonadotropin (Sigma-Aldrich, Steinheim, Germany) into the dorsal lymph sac according to Kloas et al. (1997). Fertilized eggs and larvae were maintained in 60 L tanks filled with 40 L demineralized water and mixed with 0.25 g/L sea salt (Tropic Marin, Wartenberg, Germany). The water was aerated by using airstones and the water temperature was adjusted to 22 ± 1°C. The pH-value ranged from 7.0 ± 0.5. The light-dark cycle was 12:12 h during the exposure time. Tadpoles were held under these conditions until they reached stages 48 or 51, respectively. Short-term exposure of stage 51 tadpoles

Determination of potential effects of BPA on thyroid system was accomplished by exposing tadpoles at stage 51 to BPA alone (100, 250, and 500 µg/L) and to BPA plus 0.1 nM T3 (thyroid hormone (TH)) using a semistatic exposure system (Fig. 2) (n=30, respectively). Stage 51 is particularly qualified for this kind of gene expression determination, because the thyroid gland is not yet functioning. Consequently, no endogenous TH circulate in the blood stream, but several tissues are already competent to respond very

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sensitively to exogenous addition of TH by modified gene expression patterns. Test solutions were changed daily. After 24, 48, and 72 h, head tissue was sampled to analyze the thyroid system-specific biomarker thyroid hormone receptor ß (TRß) at the gene expression level. All test chemicals (E2, BPA, T3) were purchased from Sigma (Taufkirchen, Germany). Long-term exposure of stage 48 tadpoles

To determine the effects of BPA on morphological parameter (body weight, whole body length), gonadal gross morphology and histology tadpoles at stage 48 were exposed to BPA concentrations ranging from 10-9 to 10-6 M for up to 75 days using a flow through system (Fig. 2). In parallel the natural estrogen 17ß-estradiol (E2) was used as a positive control at 0.2 µg/L. Each treatment contained 4 tanks with 7 L test solution and 25 tadpoles, respectively. At the end of metamorphosis (stage 66), body weight, whole body length and phenotypic sex was determined for all animals. Gonadal tissues were collected for histological analyses.

Fig. 2: Design of a semistatistic system and a flow through sytem.

Gene expression determination in head tissues

Total RNA of head tissues was isolated using the phenolic reagent Trizol (Invitrogen, Karlsruhe, Germany). Diluted RNA was transcribed in cDNA by reverse transcription (RT). Following the amplification of cDNA for EF1a, and TRß genes were carried out as described by Jagnytsch et al. (2005). 3.1.1.3

Results and Discussion Bisphenol A emission

The total emission of BPA into the Elbe catchment was found to be 970 kg/a by WWTP, 70 kg/a by sewer systems and 510 kg/a by two industrial discharges in the Czech part of Elbe (Fig. 3). The retention within the surface waters of Elbe is 790 kg/a or 51% The specific emission of 0.24 g/a*inhabitant was calculated. The inhabitant specific discharge out of sewage plants was calculated to be 0.056 g/a*inhabitant. No data were found to atmospheric deposition, particle entry via erosion, dissolved entry via avulsion, basis flow, interflow, and tile drainage. The calculated specific emission of BPA correspond with data

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found in literature (Fries, 2002), which specify a range 0.013-0.144 g/a*inhabitant.

33%

62% 5%

W W TP

Sew er System

Industrial discharges

Fig. 3: Total emission of BPA into Elbe catchment.

Using the retention function several BPA concentrations could be calculated for different monitoring stations among the Elbe river. The comparison of these calculated concentrations versus observed BPA concentrations has shown that most of the data were within the 30% deviation but some data were underestimated especially stations downriver of Valy (Fig. 4A). Possible reason for that could be emssions of industrial discharges like Spolchemie and Spolana in the Czech area. Considering these industrial discharges all values were within the 30% deviation of retention (Fig. 4B).

A

B

Fig. 4: Comparison of calculated and observed BPA concentrations among the Elbe river. A without industrial discharges. B with industrial discharges.

BPA determination of water samples of Elbe-river catchment

BPA was determined in water samples taken from different tributaries of the Elbe catchment. Data are given in table 1. BPA could be detected in all tested water systems. The concentrations ranged from 0-1.5 µg/L. The highest BPA concentration could be measured in WWTP Münchehofe outflow.

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Tab. 1: BPA detection in water samples of the Elbe-river catchment. The unit of the given data is ng/L. Water system

Oct 06

Nov 06

Dec 06

0

144.3

0

0

127.1

302.7

30.7

112.7

Havel/Spree (Potsdam)

363.5

268.9

20.4

43.6

WWTP Outflow Münchehofe

1062.3

347.0

1002.8

1508.1

Erpe + WWTP Münchehofe

911.8

256.2

627.0

n.d.

Elbe (Krippen)

481.9

n.d.

n.d.

n.d.

Wuhle I (Marzahn)

n.d.

137.8

n.d.

n.d.

Wuhle II (Hellersdorf)

n.d.

112.2

n.d.

n.d.

Erpe above WWTP Münchehofe

n.d.

n.d.

n.d.

547.4

Spree (Große Tränke) Havel (Hennigsdorf)

Jan 07

Short-term exposure of stage 51 tadpoles

TRß-mRNA [CHANGE vs CONTROL]

TRß mRNA expression was significantly up-regulated by 0.1 nM T3 already after 24 h and remained elevated over the entire experimental exposure until 72 h. Within 24 hours, T3 treatment caused a 4-fold higher expression of TRß gene in head tissues compared to untreated controls (Fig. 5A). The highest BPA concentration antagonized the T3-induced TRß expression at all sampling points (Fig. 5B). 250 µg/L BPA caused a significant downregulation of the T3-induced TRß expression after 48 h. In the absence of T3, BPA alone did not affect TRß expression.

10 8

SC 100 µg/L BPA + SC 250 µg/L BPA + SC 500 µg/L BPA + SC

A

0.1 nM T3 100 µg/L BPA + T3 250 µg/L BPA + T3 500 µg/L BPA + T3

6

***

B ***

***

4 2 24h

48h

72h

24h

48h

72h

Fig. 5: Relative TRß-mRNA expression after short-term exposure with BPA. A BPA compared to untreated control. B BPA compared to T3.

Long-term exposure of stage 48 tadpoles

At the end of metamorphosis, mean weight of tadpoles treated with BPA was increased in a dose dependent manner being significant already at 10-8 M BPA for males and females, respectively (Fig. 6). Mean whole body length of tadpoles exposed to BPA was also increased compared to controls (Fig. 6). This increase was significant at 10-6 M BPA for males and at 10-7 M and 10-6 M BPA for females. At the end of metamorphosis gonads were dissected for histological analyses. The exposure of males to 10-6 M BPA caused remarkable changes in gonadal gross morphology. Histological analyses of these gonads have clearly shown leackages in testicular tissues compared to control animals (Fig. 7A/B). Similar effects could be observed in males which were exposed to the natural estrogen 17ß-estradiol (E2) (Fig. 7C).

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male female

Co

*

**

***

E2 10-9 10-8 10-7 10-6

Whole body length [mm]

Total body weight [g]

1,0 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1

male female

21 20

**

***

19 18 17 16 15

Co

E2 10-9 10-8 10-7 10-6 BPA [M]

BPA [M]

Fig. 6: Total body weight and whole body length after long-term exposure with BPA.

At the end of metamorphosis gonads were dissected for histological analyses. The exposure of males to 10-6 M BPA caused remarkable changes in gonadal gross morphology. Histological analyses of these gonads have clearly shown leakages in testicular tissues compared to control animals (Fig. 7A/B). Similar effects could be observed in males exposed to E2 (Fig. 7C).

A

B

C

Fig. 7: Hematoxylin-eosin staining of male gonads of juvelile frogs: A untreated control male, B after 10 -6 M BPA treatment, C after E2 treatment.

3.1.1.4 Discussion

Biodegradation experiments have demonstrated a half-life of up to 4 days for BPA in river waters (Klecka et al. 2001). Despite it seems to be degraded rapidely after a lag phase it could be shown that BPA is permanently detectable in the Elbe River and several tributaries. Investigations about emissions have shown that mainly WWTP´s and industrial discharges are responsible for the BPA release into the Elbe catchment. A retention rate of 51 % for BPA by WWTP´s was calculated which means the absolute inflow of the WWTP´s must be twice as much. This inflow must be mainly caused by households as well as small and medium sized enterprises. Possible sources of BPA could be toilet paper,

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plastic material cleaned in a dishwasher or food rests which are disposed by sewer systems (Gehring 2004, EFSA 2006). Another source of BPA is released from PVC pipes or surface coating agents. Depending on state of the technology the retention of WWTP´s are quite different. Old WWTP´s with trickling filtration and activated sludge barely degrade BPA whereas WWTP´s using membrane filtration, nano-filtration and membrane bioreactors have a BPA elimination rate of at least 75% (Gehring 2004). The amphibian model was used to analyze effects of BPA on the thyroid and reproductive system. Several studies have evaluated that the amphibian Xenopus laevis is a valuable model to determine effects of ED on endocrine system (Opitz et al. 2002, Kloas 2002, Levy et al. 2004). TH produced and released from thyroid gland are essential for different developmental phases during metamorphosis. Interferences of ED with thyroid system can be observed by stimulation or deceleration of metamorphosis in long-term exposure. In this study a short-term exposure with BPA and a combination of TH and BPA was performed to determine effects of BPA on TRß gene expression level. TRß is an early response gene of TH. Within 24 h it responds rapidely to exogenous given TH induction in stage 51 premetamorphic tadpoles. Challenge experiment with BPA and T3 clearly demonstrated a dose response inhibitory action of BPA at concentrations of 250 and 500 µg/L BPA on TH induced gene expression of TRß. Similar inhibitory effects have been observed for TBBA which is the brominated form of BPA and a most commonly used flame retardant (Jagnytsch et al. 2006). The BPA effect was significant but less pronounced compared to that caused by TBBA. These results suggest that compounds with similar chemical structure can have similar properties. Long-term exposure with BPA has shown significant increases in mean body weight and whole body length of juvenile frogs in a dose dependent manner. Studies about effects of BPA on body weight are quite controversial. In several studies it was documented that BPA can cause an increase of single organ weights like uterus and liver in rats and mice (Papaconstantinou et al. 2000). Rubin et al. (2001) has demonstrated the increase of body weight in rat offspring treated by BPA. Further in vivo studies have shown a decrease in mouse and chicken testis weight or body weight probably caused by toxic side effects (Al-Hiyasat et al. 2002, Furuya et al. 2002). However, the natural estrogen E2 was also tested in long-term exposure as a positive control and there was no difference in body weight and whole body length seen suggesting that growth promoting effects of BPA are not induced by estrogenic modes of action but might affect regulation of insulin like growth factors. Investigations of the reproductive system were done by using long-term exposure where the positive control E2 caused 75% feminization. Remaining E2 males have mixed sex gonads or testis with leakages within the tissue. Exposure of males to 10-6 M BPA caused remarkable changes in gonadal gross morphology too. Histological analyses of these gonads also demonstrated leakages in several testicular tissues but less pronounced. From

40

E2 treatment it appeared that feminization of male gonads starts with tissue degradation and disaggregation. After a couple of time, testis changes to mixed gonads which means ovarian and testicular tissue in one gonad until just ovarian tissue is remaining. That means remarkable observation in gross morphology and histology of BPA male gonads could be evidences for beginning feminization procedures. So the tested concentrations of BPA were too low for causing complete feminization. In zebrafish 1820 µg/L BPA caused 32% ovo-testis (Yokota et al. 2000). In summary, BPA action on thyroid system is just moderate resulting in minor competition of BPA and TH on thyroid hormone receptor level or transport binding proteins. Results on gross morphology and histology are not finished yet. But these given results clearly demonstrate that higher BPA concentrations can interfere with the thyroid system probably mediated via its moderate thyroid hormone receptor binding in a competitive manner and also with the reproductive system. Lower concentrations of BPA did not show any remarkable effect. BPA is widely spread in the environment. Especially in regard to animal and human health it is necessary to improve the degradation of such compounds in WWTPs and also to minimize the release of such harmful substances by industries into to surface water. Acknowledgement

The research was funded by BMBF (GLOWA-Elbe). The authors thank Wibke Schuhmacher, Ingo Cuppok, Antje Lüder, Bernd Schütze, Björn Hermelink, and Maria Jagnytsch for technical assistance. Special thanks to Marcel Simon and Liane Wieczorek for histological assistance. References AL-HIYASAT, A. S., DARMANI, H., ELBETIEHA, A. M. (2002): Effects of bisphenol A on adult male mouse fertility. Eur J Oral Sci, Vol. 110, 163-167. BEHRENDT, H., CONSTANTINESCU, L.T., CVITANIC, I., DRUMEA, D., JABUCAR, D., JURAN, S., PATAKI, B., SCHREIBER, H.,

SNISHKO, S., ZESSNER, M. (2003):

Nährstoffeinträge und –frachten im Flusssystem der Donau - Ergebnisse einer flussdifferenzierten Modellanalyse: Nutrient inputs and loads in the Danube River system – Results of a river system oriented model analysis. ÖWAW., Heft 9-10, 1-7. BRAUNRATH, R., PODLIPNA, D., PADLESAK, S., CICHNA-MARKL, M. (2005): Determination

of

bisphenol

A

in

canned

foods

by

immunoaffinity

chromatography, HPLC, and fluorescence detection. J Agric Food Chem, Vol. 53, 8911-8917. COLBORN, T., Dumanoski, D., Myers, J. P. (1996): Our stolen future. Little Brown & Co., London. EFSA. (2006): Opinion of the scientific panel on food additives, flavourings, processing aids and materials in contact with food on a request from the commssion related to 2,2-bis(4-hydroxyphenyl)propane (bisphenol A). The EFSA Journal, Vol. 428, 1-75.

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FURUYA, M., SASAKI, F., HASSANIN, A. M. A., KUWAHARA, S., TSUKAMOTO, Y. (2002): Effects of bisphenol A on the growth of comp and testes of male chicken. The Canad J of Veterenary Res, Vol. 67, 68-71. GEHRING, M. (2004): Verhalten der endokrin wirksamen Substanz Bisphenol A bei der kommunalen Abwasserentsorgung. Doktorarbeit. http://rcswww.urz.tudresden.de/~gehring/deutsch/dt/mitar/ge/dige_lic.pdf GOODSON, A., ROBIN, H., SUMMERFIELD, W., COOPER, I. (2004): Migration of bisphenol A from can coatings - effects of damage, storage conditions and heating. Food Additives Contaminants, Vol. 21, 1015-1026. JAGNYTSCH, O.,

OPITZ,

R., LUTZ, I.,

KLOAS,

W. (2006):

Effects

of

tetrabromobisphenol A on larval development and thyroid hormone regulated biomarkers of the amphibian Xenopus laevis. Environ Res, Vol. 101, 340-348. KLOAS, W. (2002): Amphibian as a model for the study of endocrine disruptors. Int Rev Cytol, Vol. 216, 1-57. LEVY, G., LUTZ, I., KRÜGER, A., KLOAS, W. (2004): Bisphenol A induces feminization in Xenopus laevis tadpoles. Environ Res, Vol. 94, 102-111. OEHLMANN, J., SCHULTE-OEHLMANN, U., BACHMANN, J., OETKEN, M., LUTZ, I., KLOAS, W., TERNES, T. A. (2006): Bisphenol A induces superfeminization in the Ramshorn snail Marisa cornuarietis (Gastropoda Prosobranchia) at environmentally relevant concentrations. Environ Health Prospective, Vol. 114, 127-133. OPITZ, R., LEVY, G., BÖGI, C., LUTZ, I., KLOAS, W. (2002): Endocrine disruption in fish and amphibians. Recent Res Devel Endocrinol, Vol. 3, 127-170. YOKOTA, H., TSURUDA, Y., MAEDA, M., OSHIMA, Y., TADOKORO, H., NAKAZONO, A.,HONJO, T., KOBAYASHI, K. (2000): Effects of bisphenol A on the early live stage in Japanese medaka (Oryzias latipes). Environ Toxicol and Chem, Vol. 19, 1925-1930. PAPACONSTANTINOU, A. D., UMBREIT, T. H., FISHER, B. R., GOERING, P. L., LAPPAS, N. L., BROWN, K. M. (2000): Bisphenol A-induced increase in uterine weight and alterations in uterine morphology in ovariectomized B6C3F1 Mice: Role of the estrogen receptor. Toxicol Sci, Vol. 56, 332-339. PICKFORD, D. B.., HETHERIDGE, M. J., CAUNTER, J. E., TILGHMAN HALL, A., HUTCHINSON, T. H. (2003): Assessing chronic toxicity of bisphenol A to larvae of the African clawed frog (Xenopus laevis) in a flow-through system. Chemosphere, Vol. 53, 223-235. RUBIN, B. S., MURRAY, M. K., DAMASSA, D.A., KING, J.C., SOTO, A. M. (2001): Perinatal exposure to low doses of bisphenol A affects body weight, patterns of estrous cyclicity, and plasma LH level. Environ Health Persp, Vol. 109, 675-680. YOSHIDA, M., SHIMOMOTO, T., KATASHIMA, S., WATANABE, G., TAYA, K., MAEKAWA, A. (2004): Maternal Exposure to low doses of bisphenol A has no effects on development of female reproductive tract and uterine carcinogenesis in Donryu rats. J of Reprod and Develop, Vol. 50, 349-360.

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3.2 Research Topic 2 Forschungsschwerpunkt 2

Processes at interfaces Prozesse an Grenzflächen

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H ILT , S., S CHÖNFELDER ,I., R UDNICKA , A., C ARLS , R., N IKOLAEVICH , N., S UKHODOLOV , A., E NGELHARDT , C.

3.2.1 Reconstruction of pristine morphology, flow, nutrient conditions and submerged vegetation of lowland River Spree (Germany) from palaeomeanders Rekonstruktion der Referenzbedingungen der Unteren Spree hinsichtlich Morphologie, Abfluss, Nährstoffkonzentrationen und Unterwasservegetation aus Paläomäandern

Key words: bankfull palaeodischarge, diatoms, macrofossil remains, macrophytes, nutrient concentrations, reference conditions, water framework directive, lowland river Abstract

The European Water Framework Directive requires the definition of reference conditions for each type of surface waters as a base to establish a classification system in which deviations from this high quality status must be determined. In order to reconstruct pristine conditions in the lower River Spree we investigated palaeomeanders using palaeohydrological and palaeolimnological methods. Reconstructions show narrower and shallower channels for the undisturbed lower Spree as compared to recent conditions. Flow velocities and discharge at bankfull stage have been smaller in reconstructed sub-fossil channels and flow variability was higher. Diatominferred total phosphorus concentrations indicate eutrophic to hypertrophic conditions and suggest naturally slightly lower nutrient levels than today. These past nutrient conditions, morphology and large numbers of macrofossil remains indicate optimum growth conditions for submerged macrophytes growth. Zusammenfassung

Die EU-Wasserrahmenrichtlinie fordert für jeden Gewässertyp die Definition von Referenzbedingungen als Grundlage für ein Klassifizierungssystem, das auf Abweichungen von diesem Status höchster Qualität beruht. Um die Referenzbedingungen der Unteren Spree zu rekonstruieren wurden Paläomäander mittels paläohydrologischer und paläolimnologischer Methoden untersucht. Die unbeeinflusste Untere Spree war im Vergleich zu heutigen Bedingungen enger und flacher. Die Fließgeschwindigkeiten und der Abfluss im bordvollen Zustand waren geringer und die Variabilität der Fließgeschwindigkeiten höher. Die über Diatomeen-Analysen rekonstruierten Gesamtphosphorkonzentrationen waren etwas geringer als die aktuellen und indizieren eutrophe bis hypertrophe Bedingungen für den Referenzzustand. Eutrophe Bedingungen sowie die rekonstruierte Morphologie und große Mengen makrofossiler Reste submerser Makrophyten deuten auf optimale Bedingungen für die Entwicklung submerser Makrophyten.

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3.2.1.1

Introduction

The European Water Framework Directive (Directive 2000/60/EC of the European Parliament), potentially the most significant piece of legislation ever to be enacted in the interest of conservation of fresh and saline ecosystems, requires the restoration of aquatic habitats to a so-called good ecological status. For each ecotype, reference conditions must be defined as a base to establish a classification system in which deviations from this pristine status must be determined. Establishment of reference conditions from existing sites is difficult as there are few, if any, such sites available in Europe (Moss et al. 2003). Thus, there is a need to determine the reference conditions, for example with palaeoecological reconstructions. Reconstructions increase in significance when multiple palaeoindicators are used (Brown 2002), e.g. when the reconstruction relies on both palaeohydrological and palaeolimnological parameters. The following study was carried out to reconstruct the reference conditions regarding hydromorphology, flow characteristics, bankfull discharge, nutrient conditions and the aquatic vegetation in the lower River Spree (North-eastern Germany). Palaeomeanders suitable for these reconstructions were identified using aerial infrared photographs, sedimentological analyses of sediment cores from transects across palaeomeanders and geodetic surveys. For the reconstruction of the bankfull palaeodischarge, a model was developed that includes a parametrization of the velocity distribution in the recent river channel under local conditions of flow resistance, thus, avoiding the empirical formulas commonly used in palaeohydrological reconstruction. Over longer time scales (decades and centuries) a meandering river forms a channel, which is able to transport the amount of water and sediment supplied by the catchment basin (Leopold 1994). This quasi-equilibrium between discharge and channel morphology of pristine rivers is the prerequisite for the reconstruction of hydrological characteristics using palaeochannels. The relationship between the reconstructed channel morphology and the unknown palaeodischarge is often defined through a single, dominant discharge that produces the observed channel. It is often assumed to be close to bankfull (Lauer & Parker 2006). Thus the key to determining discharge under undisturbed flow conditions (hydraulic reference conditions) is the reconstruction of the only water stage that leaves a clear trace in the morphology of a river channel, the stage of the so-called bankfull discharge (Rotnicki 1991). Palaeolimnological reconstructions can be used when sediments accumulate in continuous sequences, for example, in deep lakes (e.g. Lotter 2001) and often also in shallow lakes (e.g. Bennion et al. 2001). In rivers, which have high sediment dynamics, continuous sedimentation is limited to low current areas (e.g. deposition zones at the inner bank of the meander loop). Thus, cores drilled across a meander apexes would (at the inner bank) contain settled material that, at least partly, consists of autochthonous microand macrofossils from the flowing river. The succession of any meandering river further emphasises that meander loops are characterized mainly by

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expansion until the meandering pattern is destroyed by a cut-off. Once abandoned these former parts of the main river channel accumulate sediments that still contain river-borne material that enters the oxbow lake during flooding events, but an increasing share of material characterizing the oxbow-lake-stage. The latter can be distinguished from the flowing-riverstage by its sediment texture and changes in the phytoplankton and macrophytes species composition. Macrofossils of palaeomeanders only partly originate from the main river, but can be used to reconstruct pristine river conditions when used in combination with information on hydromorphological conditions and nutrient concentrations.

3.2.1.2

Material and Methods

In order to find suitable palaeomeanders for the reconstruction of pristine hydrological and limnological conditions of the lower River Spree we used colour-infrared (CIR) aerial photographs of the Drahendorfer Spree. In a first step we selected all palaeomeanders with exact delimitation and a complete meander bend. Afterwards sediment cores were taken in the apex, and meanders showing a clear boundary between the active channel documented by mineral material (especially sand and gravel) and the silting up material (muds, peat) were selected for further investigation. Subsequently, cross profiles were determined by sediment core drillings in the apex domain of the selected meanders. Palaeomeanders suitable for the calculation of the cross-sectional area at bankfull stage were dated and those representing periods with low anthropogenic impact used for the analysis of diatoms and macrofossil remains to reconstruct nutrient concentrations and the colonization with aquatic macrophytes, respectively. Detailed information about the methodology can be found in Hilt et al. (2007).

Fig. 1:. Reconstructed vertical cross-section and bankfull stage of investigated palaeomeander and approximation of the detected cross-profile by a parabolic function

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3.2.1.3

Results

TN :T P

Diatom Zone

(m g* l -1)

DI -

DI -T N

0

Ac hn a Fr nth a e Ac gila s h hn ria un Na a ca ga vic nth pu ric e a Au ula s m cina (G la pu in va run co p u o se ula tiss r. m w) ira K im es G Au gr ützi a K ole run la ng üt pt ow co an z se ul va in a (R at ira sm a ( r. p g va ab am Eh up r. en al lb u m h re bi en gu nb la inu ors th a ( er tis t) Au ic G g) sim Ra la Fr r u Si Co co ag no a ben m ila c s w on ho Cy co eira ) r i se rs Si as clo nei la t m n pp G s s e se on om te pl vis . ns se Fr ph ph ace sim u n ag o an n a la t n to St ila e os ul (G a e r m r M pha ia u a p dub var uno el n ln a iu . li w o o a rv s n ) G sira disc (Ni ulu (Fri eat Kra om v u tzs m ck a m c (K e) (E m p ar s G hon ians neo h ) L ütz Ro hre er o e A a a in u n Fr mph ma gastra nge g ) Knd ber g) ag o -B ü m rd e Va # ilar nem icr h a Ha ert tzin nH of ia a op ka alo g v ta ca s eu ns t v ar xa p ar us K rc s a uc co üt on r. . pa k u zin in ph & ln rvu ao a DI g a H -T th gu ick se lum er s G P el ns (µ v r u ar eg g* la s . or l -1) to y

Of 15 palaeomeanders identified from aerial photographs of the floodplain of the Drahendorfer Spree, eight were suitable for the reconstruction of hydromorphological characteristics (see Fig. 1 in Hilt et al. 2007). Following dating, three sites (in downstream order D5, D7, D1) were chosen for further calculations as they represent periods of low anthropogenic impact. Channel width at bankfull stage varied between 16 and 21.5 m and mean depth between 0.64 and 0.99 m. A flow model was developed for the reconstruction of bankfull flow characteristics and discharge of the lower River Spree (for details see Hilt et al. 2007). This model was applied to the surveyed morphometrical data of the palaeomeanders D5, D7, and D1. Their cross-sections were approximated by a parabolic function (Fig. 1). Using the bankfull stage, flow velocity at each point of the cross-section was calculated using a closed system of analytical equations (Hilt et al. 2007). Integration of the calculated flow velocities over the cross-sectional area results in the mean flow velocity. Calculated bankfull discharges varied between 5.5 and 10.3 m³ s-1 (Table 1).

10

Core depth (cm)

20 30 40

II

50 60 70 80 90

I

100 0 20

0 20 40 20 0 20 Relative diatom abundance (%)

0 20

20

80 120 30 90 150 0.8

2.4

10 20 30

Fig. 2: Relative abundance of important diatom taxa, number of differentiated taxa, diatominferred total phosphorus (DI-TP), DI-total nitrogen (TN) and DI-TN:TP in a sediment core of palaeomeander D5 of the Drahendorfer Spree.

Diatom-based reconstructions were performed for the core of palaeomeander D5. The diatom assemblage can be divided into two zones (Fig. 2). Zone I (105-85 cm, ~1100–500 BC) was characterized by benthic Achnanthes hungaria (Grunow) Grunow (3-13%), Achnanthes minutissima Kützing var. minutissima (1-5%) and Navicula pupula Kützing var. pupula (05%), as well as tychoplanktonic Fragilaria capucina var. mesolepta (Rabenhorst) Rabenhorst (1-6%). Zone II (80-1 cm, ~500 BC to 2003) was characterized by increased abundances of planktonic Aulacoseira ambigua (2-23%) and Aulacoseira granulata (4-34 %), as well as taxa typically found in bogs, such as taxa from the genus Eunotia and Pinnularia. Additionally, small, benthic Fragilaria spp. (F. brevistriata Grunow, F. construens (Ehrenberg) Grunow f.,

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construens, F. construens f. binodis (Ehrenberg) Hustedt and F. construens f. venter (Ehrenberg) Hustedt), Gomphonema micropus Kützing, Gomphonema sarcophagus Gregory, as well as planktonic Aulacoseira laevissima (Grunow) Krammer and tychoplanktonic Melosira varians Agardh, which occurred in low abundances in zone I (together < 18%), comprised 11-32% of the assemblage in zone II. Diatom-inferred total phosphorus (DI-TP) increased from 59-73 µg L-1 in zone I to 59-98 µg L-1 in zone II, while DI-TN hardly changed throughout the core (median zone I = 1.3 mg L-1, median zone II = 1.5 mg L-1) (Fig. 2). Macrofossil remains of both, submerged or floating-leaved plants (seven taxa) and emergent aquatic plants (eight taxa) were found at the base of palaeomeander cores D5, D7 and D1. For example; seeds of the submerged genus Ranunculus sect. Batrachium were present in all three meanders. In contrast, remains of submerged or floating-leaved species were absent in the upper sediments (except for Lemna spp.; core D5, zone II in Fig. 3), whereas most emergent species were found throughout the core (Fig. 3).

Floating

Emergent

Po ta m

og et on

ob tu si fo liu s

R an St unc ra ul tio us te s N s ec ym al t. oi B de a N ph up ae s tra ch Le har a a iu m lu lba m Al na tea is sp m p a . pl an ta go O -a en qu an at t he ic M a en aq th u a a aq tica Ly au co tic C pu ar s a ex eu sp rop Ju p. a eu nc s Sc us irp sp us p. sp p.

Submerged

0 10 Core depth (cm)

20 30 40 50 60 70 80 90 100 110 0

20 40 60 0

0

20

0

0 0

20 40

20

20

0

20

Macrofossil remains (n * 100 ml-1)

Fig. 3: Macrofossil remains in a sediment core of palaeomeander D5 of the Drahendorfer Spree.

3.2.1.4

Discussion

The palaeomeanders investigated in our study represent reference conditions of the lower River Spree. AMS dating suggests that the sediments at the base of three investigated cores (D5, D7 and D1) represent the late Subboreal/early Sub-atlantic, a time of low anthropogenic impact in the catchment of the River Spree (Bork et al. 1998, Driescher & Behrendt 2002). The pristine lower River Spree had narrower and shallower channels compared to the recent river (Table 1). Both mean flow velocities at bankfull stage were slower and flow variability was higher in the reconstructed subfossil channels of the Lower Spree.

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Tab. 1: Hydrological characteristics at bankfull discharge of the recent (meander near Neubrück) and the pristine lower River Spree (mean of palaeomeanders D5, D7, D1).

Discharge Meander slope Mean width at bankfull stage Mean depth at bankfull stage Mean flow velocity Local characteristic (shear) velocity

Recent

Reconstructed

51.7 m³ s -1 0.00005 35.2 m 1.63 m 0.9 m s -1 2.8 cm s -1

8.2 m³ s -1 0.00008 19.6 m 0.79 m 0.53 m s -1 2.4 cm s -1

Palaeohydrological reconstructions are all subject to error, because of limited or unreliable data or simplifications inherent to model formulas (Williams 1988). Our newly derived approach to identify suitable palaeomeanders for reconstructions using aerial photography in combination with geomorphology resulted in rather robust hydromorphological data sets. The estimation of bankfull discharge by planar parameters of a palaeomeander such as width (e.g. Durys (1977) formula) or width and sinuosity (e.g. Rundquists (1975) formula) is mostly less accurate (Knighton 1998) than that from a combination of planar, cross-sectional parameters, and slope (e.g. Williams` (1978) formula). Hydraulically based equations for discharge as those developed by Grishanin (1979) or Rotnicki (1991) additionally involve the flow resistance to which the velocity (and thus the discharge) is strongly related. Our model calculates the flow velocity distribution over a bankfull cross-sectional area directly, using a parametrization developed from field data in the recent Drahendorfer Spree. Discharge in this model yields from the mean cross-sectional velocity and the area at bankfull discharge. Our bankfull discharge reconstruction is in good agreement with the more complex models of Williams (1978) and Rotnicki (1991). Our model is more sensitive to the local slope of the meander than the most advanced models of Williams (1978) and Rotnicki (1991), where slope occurs with the exponent 0.28 and 0.5, respectively. To illustrate the uncertainty of the modelled bankfull discharge, the maximum possible (slope of the floodplain) and the minimum possible slope (detected slope of the recent Drahendorfer Spree measured in field) was used instead of slope calculated by the equation for meandering rivers (Hilt et al. 2007). The resulting maximum bankfull discharge values for D1, D7, D5 are then 11.2 m³ s-1, 5.8 m³ s-1 and 9.3 m³ s-1, respectively; the minimum values are 8 m³ s-1, 3.9 m³ s-1, and 6.3 m³ s-1, respectively. When these three palaeomeanders are considered, the modelled mean bankfull discharge is 8.2 m³ s-1 (6.1-8.7 m³ s-1, Table 1). In sand-bed rivers, the grain roughness (which is expressed by Manning´s number in Rotnicki`s formula) is often less important than other components of the total flow resistance resulting from frictional effects at the bank and the bed of the channel. The flow model presented here includes these effects and should therefore minimize the error usually associated with reconstructed bankfull discharge. The difference between the recent (~52 m³ s-1) and the reconstructed (~8 m³ s-1) bankfull discharge of the Lower River Spree can only partly be explained by the current additional input of mining water into the Spree (~14 m³ s-1). Similarly, climatic conditions in Central Europe did not change

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dramatically during the last 3000 years (Lamb 1977, Glaser 2001) and can therefore not fully explain the discharge increase either. For example, using a macrophysical runoff model driven solely by climatic data, Bryson et al. (2003) simulated a less than 10% greater discharge of Central European Rivers in the middle Holocene than today. In contrast, many examples indicate that river discharge may greatly increase when natural vegetation is cleared (Bosch & Hewlett 1982, Sahin & Hall 1996, Foley et al. 2005) as deforestation alters both the balance between rainfall and evapotranspiration and the runoff response of a drainage basin. In Germany, the forested area declined from 90% in the 6th century to 15% in the early 14th century (Schmidtchen & Bork 2003). Furthermore, channelization, bank protection and river regulation measures, typical for the River Spree (Driescher 2002), also increase flow velocity and transport capacity of a river. For example, bankfull discharge of the River Raba (Poland) increased by a factor of 2.4 after channelization due to reduced floodplain storage and greater concentration of water within the channel zone (Wyzga 1996). Therefore, land-use changes and river straightening were probably responsible for most of the inferred discharge changes in the lower River Spree. Diatom assemblages in zone I of the investigated core of palaeomeander D5 are assumed to represent reference conditions of the River Drahendorfer Spree for the following reasons: 1) Dating techniques suggest that zone I represents ~1100-500 BC, a time in which the study area was hardly inhabited (Driescher & Behrendt 2002). Therefore, anthropogenic impact on the water quality was probably very low or absent in zone I. 2) Taxa present in diatom zone I are typical taxa from the River Drahendorfer Spree. For example, in the River Drahendorfer Spree many planktonic diatoms, such as Aulacoseira laevissima, originate in Lake Schwielochsee (I. Schönfelder, unpublished data), which is located just 12 km upstream of the study site. These taxa were abundant in zone I. Additionally, taxa typically reflecting oxbow rather than river conditions were almost absent in zone I, but common in zone II, such as taxa typically found in bogs. Overall, diatominferred chemical water conditions in zone I suggest that the Drahendorfer Spree had naturally eutrophic to hypereutrophic nutrient levels. Still, reference TP levels (~ 62 µg L-1) are lower and reference TN levels (~ 1.3 mg L-1) slightly lower than today (94 µg L-1 and 1.8 mg L-1, respectively). Naturally high nutrient levels could be due to the geology of the catchment area (Driescher 2002). Another possible source of nitrogen is Lake Schwielochsee, which probably had naturally favourable conditions for nitrogen-fixing blue-green algae during the summer months (I. Schönfelder, unpublished data). Similarly high or even higher nutrient reference conditions were inferred for flushed lakes and river reaches both up- and downstream of Drahendorfer Spree (Hilt et al. 2007) as well as other lakes in the vicinity and in River Havel (Schönfelder 1997). The reconstructed low water depth (Table 1), diatom-inferred eutrophic to hypertrophic conditions and large numbers of macrofossil remains

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indicate optimum growth conditions for submerged macrophytes in the pristine lower River Spree. Due to the shallow water and the small river width (Table 1), the main limiting factor for submerged macrophytes in the pristine lower River Spree has probably been shading by bankside trees (Dawson & Kern-Hansen 1978). Higher flow variability generally results in a less uniform colonization and higher species diversity (Hey et al. 1994). In addition to submerged species of the genera Ranunculus sect. Batrachium (Water-crowfoot) and Potamogeton (pondweeds) that were detected by seeds, other species probably also occurred under pristine conditions. Birks (2000) already pointed out that lack of seed representation may result from vegetative production for survival. In reaches with higher flowing velocities and water depths above 1 m, a community dominated by River Watercrowfoot (Ranunculus fluitans) may have occurred, whereas slow flowing stretches were probably dominated by species-rich Sparganium emersum communities comparable to the present vegetation in the River Müggelspree (Schulz et al. 2003). Similar to the diatoms, all submerged and emergent macrophyte species detected indicate eutrophic conditions (Krausch 1996). Acknowledgement

We acknowledge the help of Lina Wischnewsky and Arthur Brande during macrofossil counting and determination, Christiane Herzog and Jörg Gelbrecht during diatom preparation, Petra Werner for linguistic improvements and Matthias Rehfeld-Klein, Jörg Schönfelder, Jan Köhler and Martin Pusch for scientific discussions. The study was financially supported by the Senate of Berlin. References BENNION, H., APPLEBY, P., PHILLIPS, G.L. (2001): Reconstructing nutrient histories in the Norfolk Broads, UK: implications for the role of diatom-total phosphorus transfer functions in shallow lake management. Journal of Paleolimnology, 26, 181-204. BIRKS, H.H. (2000): Aquatic macrophyte vegetation development in Krakenes Lake, western Norway, during the late-glacial and early-Holocene. Journal of Paleolimnology, 23, 7-19. BORK, H.R., DALCHOW, C., DOTTERWEICH, M., SCHATZ, T., SCHMIDTCHEN, G. (1998): Die Entwicklung der Landschaften Brandenburgs in den vergangenen Jahrtausenden. In: KLEMM, V., DARKOW, G., BORK, H.R. (eds.) Geschichte der Landwirtschaft Brandenburgs. Verlag Mezógazda, Budapest, 237-258. BOSCH, J.M., HEWLETT, J.D. (1982): A review of catchment experiments to determine the effect of vegetation changes on water yield and evapotranspiration. Journal of Hydrology, 55, 3-23. BROWN, A.G. (2002): Learning from the past: palaeohydrology and palaeoecology. Freshwater Biology, 47, 817 – 829. BRYSON, R.A., COE, M.T., KOHFELD, K.E. (2003): Simulating the Late Pleistocene/Holocene record of river discharge in Europe. XVI INQUA Congress, Reno, Nevada.

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DAWSON, F.H., KERN-HANSEN, U. (1978): Aquatic weed management in natural strams: the effect of shade by the marginal vegetation. Verhandlungen Internationale Vereinigung Limnologie, 2, 1429-1439. DRIESCHER, E. (2002): Die Spree und ihr Einzugsgebiet - Naturräumliche Gegebenheiten und Landschaftsentwicklung. In: KÖHLER, J., GELBRECHT, J., PUSCH,

M.

(eds.):

Entwicklungsmöglichkeiten.

Die

Spree

Limnologie

–

Zustand,

aktuell

10,

Probleme

und

Schweizerbart’sche

Verlagsbuchhandlung, Stuttgart, 1-25. DRIESCHER, E., BEHRENDT, H. (2002): Nutzungsansprüche an die Spree und ihr Einzugsgebiet. In: KÖHLER, J., GELBRECHT, J., PUSCH, M. (eds.): Die Spree – Zustand, Probleme und Entwicklungsmöglichkeiten. Limnologie aktuell 10, Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, 26-36. DURY, G.H. (1977): Underfit streams: retrospect, perspect and prospect. In: GREGORY, K.J. (ed.): River Channel Changes. John Wiley and Sons, Chichester, 281–293. FOLEY, J.A., DEFRIES, R., ASNER, G.P., BARFORD, C., BONAN, G., CARPENTER, S.R., CHAPIN, F.S., COE, M.T., DAILY, G.C., GIBBS, H.K., HELKOWSKI, J.H., HOLLOWAY, T., HOWARD, E.A., KUCHARIK, C.J., MONFREDA, C., PATZ, J., PRENTICE, I.C., RAMANKUTTY, N., SNYDER, P.K. (2005): Global Consequences of Land Use. Science, 309, 570 – 574. GLASER, R. (2001): Klimageschichte Mitteleuropas - 1000 Jahre Wetter, Klima, Katastrophen. WBG, Darmstadt. GRISHANIN, K.V. (1979): Dinamika ruslovikh potokov. Gidrometeoizdat, Leningrad. HEY, R.D., HERITAGE, G.L., PATTERSON, M. (1994): Impact of flood alleviation schems on aquatic macrophytes. Regulated Rivers: Research & Management, 9, 103-119. HILT, S., SCHÖNFELDER, I., RUDNICKA, A., CARLS, R., NIKOLAEVICH, N., SUKHODOLOV, A., ENGELHARDT, C. (2007): Reconstruction of pristine morphology, flow, nutrient conditions and submerged vegetation of lowalnd River Spree (Germany) from palaeomeanders. River Research and Applications, in press. KNIGHTON, D. (1998): Fluvial forms and processes a new perspective. Edward Arnold, London. KRAUSCH, H.D. (1996): Farbatlas Wasser- und Uferpflanzen. Ulmer, Stuttgart. LAMB, H.H. (1977): Climate: present, past, and future. Vol. 2: Climatic history and the future. Methuen, London. LAUER, J.W., PARKER, G. (2006): Response of a simple channel network to postglacial sea level rise. In: Parker, G., Garcia, M. (eds.): River, Coastal and Estuarine Morphodynamics: RCEM 2005. Taylor& Francis, London, 697-707. LEOPOLD, L.B. (1994): A View of the River. Harvard University Press, Cambridge. LOTTER, A.F. (2001): The palaeolimnology of Soppensee (Central Switzerland), as evidenced by diatom, pollen, and fossil-pigment analyses. Journal of Paleolimnology, 25, 65-79. MOSS, B., STEPHEN, D., ALVAREZ, C., BECARES, E., VAN DE BUND, W., COLINGS, S.E., VAN DONK, E., DE EYTO, E., FELDMANN, T., FERNANDEZ-ALAEZ, C., FERNANDEZ-ALAEZ, M., FRANKEN, R.J.M., GARCIA-CRIADO, F., GROSS, E.M., GYLLSTRÖM, M., HANSSON, L.A., IRVINE, K., JÄRVALT, A., JENSEN, J.P.,

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JEPPESEN, E., KAIRESALO, T., KORNIJOW, R., KRAUSE, T., KÜNNAP, H., LAAS, A., LILL, E., LORENS, B., LUUP, H., MIRACLE, M.R., NOGES, P., NOGES, T., NYKÄNEN, M., OTT, I., PECZULA, W., PETERS, E.T.H.M., PHILIPS, G., ROMO, S., RUSSELL, V., SALUJOE, J., SCHEFFER, M., SIEWERTSEN, K., SMAL, H., TESCH, C., TIMM, H., TUVIKENE, L., TONNO, I., VIRRO, T., VICENTE, E., WILSON, D. (2003): The determination of ecological status in shallow lakes – a tested system (ECOFRAME) for implementation of the European Water Framework Directive. Aquatic Conservation: Marine and Freshwater ecosystems, 13, 507-549. ROTNICKI, K. (1991): Retrodiction of paleodischarges of meandering and sinous alluvial rivers and its paleoclimatic implications. In: STARKEL, L., GREGORY, K.J., THORNES, J.B. (eds.). Temperate Palaeohydrology: Fluvial Processes in the Temperate zone During the Last 15,000 Years. John Wiley & Sons, Chichester, 430 – 471. RUNDQUIST, L.A. (1975): A classification and analysis of natural rivers. Colorado State University, Fort Collins, Colorado, PhD Thesis. SAHIN, V., HALL, M.J. (1996): The effects of afforestation and deforestation on water yields. Journal of Hydrology, 178, 293-309. SCHMIDTCHEN, G., BORK, H.R. (2003): Changing human impact during the period of agriculture in Central Europe: the case study Biesdorfer Kehlen, Brandenburg, Germany. In: LANG, A., HENNRICH, K., DIKAU, R. (eds.). Long term hillslope and fluvial system modelling. Springer Verlag, Berlin, 183-200. SCHÖNFELDER, I. (1997): Eine Phosphor-Diatomeen-Relation für alkalische Seen und Flüsse Brandenburgs und ihre Anwendung für die paläolimnologische Analyse von Auensedimenten der unteren Havel. Diss. Bot., 283, 1-48. SCHULZ, M., RINKE, K., KÖHLER, J. (2003): A combined approach of photogrammetrical methods and field studies to determine nutrient retention by submersed macrophytes in running waters. Aquatic Botany, 76, 17-29. WILLIAMS, G.P. (1978). Bankfull discharge of rivers. Water Resources Research, 14, 1141-1158. WILLIAMS, G.P. (1988): Paleofluvial estimates from dimensions of former channels and meanders. In: Baker, V.R., Kochel, R.C., Patton, P.C. (eds.): Flood geomorphology. Wiley, Chichester, 321-334. WYZGA, B. (1996): Changes in the magnitude and transformation of flood waves subsequent to the channelization of the Raba River, Polish Carpathians. Earth Surface Processes and Landforms, 21, 749-763.

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W IESE , B., N ÜTZMANN , G.

3.2.2 Infiltration of surface water into groundwater under transient pressure gradients Infiltration von Oberflächenwasser in den Grundwasserleiter bei instationären Druckgradienten

Key words: surface water, groundwater, bank filtration, infiltration, leakage coefficient, numerical modelling Abstract

Several kinds of managed aquifer recharge techniques provide very good purification of surface water since more than 100 years. In order to maintain a reliable supply of clean water, they are becoming increasingly popular all over the world. Especially bank filtration methods require low technical effort. Exemplarily, at a test site at Lake Tegel, Berlin, Germany, the hydraulic processes of infiltration are modelled. By means of 3D long term regional and transient hydraulic modelling it was detected that the existing approaches for determining the leakance induce large errors in the water balance and describe the infiltration zone insufficiently. The leakance could be identified to be triggered by the groundwater table, causing air exchange and intrusion of atmospheric oxygen, which reduces clogging by altered redox conditions by at least one order of magnitude. This causes that changes of the groundwater table are mitigated much more than previously assumed. Taking these findings into account, a transient water balance is determined and bank filtration ratios are quantified. Zusammenfassung

Seit mehr als 100 Jahren wird Oberflächenwasser mit verschiedenen Verfahren versickert, wobei sich dessen Qualität stark verbessert. Sie finden zunehmend weltweit Anwendung, um eine zuverlässige Versorgung mit sauberem Trinkwasser zu gewährleisten. Insbesondere die Uferfiltrationstechnik erfordert nur einen geringen technischen Aufwand. Am Beispiel eines Untersuchungsgebiets am Tegeler See in Berlin werden die hydraulischen Prozesse modelliert. Die regionale, instationäre und 3-dimensionale Modellierung eines langen Zeitraums zeigt, dass die bisher verwendeten linearen Ansätze zur Beschreibung der Durchlässigkeit der Kolmationsschicht sowohl die infiltrierten Wassermengen als auch die Infiltrationsprozesse nur unzureichend wiedergeben. Grundwasserpiegelschwankungen werden stärker als bisher angenommen gedämpft. Als Folge dieser Wasserspiegelschwankungen wird die Bodenluft in der ungesättigten Bodenzone ausgetauscht und Sauerstoff eingetragen. Auf diese Weise erhöht sich die Durchlässigkeit der Kolmationsschicht um mindestens eine

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Größenordnung. Auf Grundlage dieser Ergebnisse wurden eine instationäre Wasserbilanz aufgestellt und die Uferfiltratanteile bestimmt.

3.2.2.1

Introduction

During bank filtration horizontal or vertical collector wells induce a hydraulic gradient which causes infiltration of surface water into the aquifer. During the underground passage mechanical as well as biogeochemical reactions proceed, substantially improving the water quality regarding suspended solids, algae, pathogens and other bacteria, algal toxins, dissolved organic carbon, nitrate, organic pollutants and pharmaceutical residues. These constituents are eliminated or significantly reduced, peak concentrations of the surface water are mitigated. In Europe, predominatly river bank filtration is used (Doussan et al. 1993, Grischek et al. 2003), and especially in lowland regions, where shallow lakes form a part of river system, bank filtration was operated also at lakes (Miettinen et al. 1997, Fritz et al. 2004). For the quantitative and qualitative management of bank filtration systems, flow velocities, travel times and infiltration capacities need to be known. The latter is the crucial point because it depends on well operation and hydraulic resistance of lake bed sediments, also affecting by clogging. The permeability of river beds is known to be time variable because of continuous change by shear stress, bed load transport, discharge, water level fluctuation and other factors (Huettel et al. 2003). Exchange coefficients between lakes and groundwater are not reported to be time-variant, neither under natural nor anthropogenic conditions. The bank filtration system at Lake Tegel, NW of Berlin, is characterized by highly transient well operation whereby hydraulic head differences between lake and groundwater show strong temporal variations. To model the groundwater response, however, the dynamic infiltration from surface water into the adjacent aquifer cannot be simulated assuming a linear relationship, where the water fluxes across the aquatic sediment surface is proportional to the hydraulic head differences, and the unknown factor is defined as leakage coefficient (Bear 1972). The observed highly variable infiltration dynamics reveal that typically used boundary conditions of third order or something like that are insufficient. Previously applied nonlinear approaches regarding depthdependent changes of permeability and temperature effects also could not describe the mechanisms (Schubert 2002, Lin et al. 2003, Holzbecher et al. 2006). They do neither quantify the mass transfer fluxes nor its spatial distribution. Here a gap in mechanistic understanding and modelling approaches of exchange between surface water and groundwater exists. The present study discussed infiltration behaviour of a lake bank filtration system, showing transient infiltration dynamics on different temporal and spatial scales. Different assumptions about mathematical formulation and distribution of leakage are made and expressed in four differing paramatrizations. The goodness of tempospatial infiltration characteristics is assessed by comparison with time-series of hydraulic heads,

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in situ infiltration measurements and geochemical data. The comprehensive interpretion shows that infiltration can only be described sufficiently when leakage is modelled transiently, considering the interaction of water flow, air flow in the unsaturated zone and biological processes in the clogging layer. 3.2.2.2

Material and Methods Investigation area

The investigated area is located at Lake Tegel in the NW of Berlin, Germany (Figure 1). Here, Berlin largest waterworks is pumping about 45 million m3 per year from 6 well fields around the lake and from two on the islands. This affects groundwater flow within an area of 50 km2.

Fig. 1: Lake Tegel and adjacent well fields. Small red dots indicate vertical collector wells, the red circle on Scharfenberg indicates a horizontal collector well. GWA denotes groundwater recharge ponds.

The two upper aquifers in the model domain as well as Lake Tegel itself are formed during the Saale ice-age. The 1st aquifer is unconfined consists of fine to coarse sand, has a thickness of about 15 m and a hydraulic conductivity of about 3.5*10-4 m/s. The 2nd and main aquifer also consists of fine to coarse sand with a thicknes between 25 to 50 m, covered by a glacial till of about 4 m thickness. The hydraulic conductivities range from 2*10-4 m/s to 5.5*10-4 m/s. In this 2th aquifer the vertical collector wells are screened. Both aquifers are hydraulically well connected. Hydraulic Modelling

The model domain is depicted in Figure 2, including the two upper aquifers, where the waterweorks abstracts raw water. In order to focus on the

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infiltration process at the Lake Tegel and to avoid a large-scale regional model set-up, the size of the model is reduced through the appropriate choice of boundary conditions, which are discussed in detail in Wiese (2006). Simulation is carried out between January 1st 1998 and April 30th 2005. The first 90 days are simulated steady state; afterwards simulation is transient with weekly discretization. Spatially the model is discretized by 7 layers, with a thickness between 4 m and 8 m, the horizontal cell size varies between 5 * 5 m close to the transect to 15 * 50 m next to the boundary. The model is set up under PMWinPro7 (WebTech360 2003) with the flow model of MODFLOW (Harbaugh et al. 2000).

Fig. 2: Top view on the model domain with boundary conditions. The coloured symbols indicate observation wells.

Parameter estimation

The focus of the model calibration is set to an adequate description of the leakage because this study showed that it is the most sensitive parameter. As shown in Figure 3, simulation of hydraulic head time series doesn’t match the observed ones using overall constant leakage coefficients. With high leakage in shallow water decreasing to zero at 5 m depth, the model calculates too large infiltration rates or is entirely drained. Therefore, the model is parametrized as follows. Four scenarios (cases) are derived based on different assumptions about the description of infiltration (Wiese 2006). For case 1 to case 3, the spatially distribution of the leakage is defined by 8 zones (or parameters), each comprising an elevation interval of 1 m between 25 m and 32 m NN, see Figure 4.

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Fig. 3: Observed and measured piezometric heads at observation well TEG050 with two temporally and spatially constant leakage coefficients.

In case 2 and 3 their values are additionally multiplied by a timedependent function, so that the temporal and spatial distribution of the leakage could be modelled. For case 4 it is assumed that the leakage is triggered temporally and spatially by the thickness of the unsaturated zone below the infiltration area. Thus, the numbers of parameters to be fitted are different for each case: 9 parameters for case 1, 11 parameters for case 2, 54 parameters for case 3 and 5 parameters for case 4.

Fig. 4: Spatial distribution of the depth dependent leakage. Each colour represents one parameter.

Due to the great impact of infiltration, the hydraulic conductivity of the aquifer is insensitive to calibration. The hydraulic model has been calibrated using PEST (Doherty 2003). Because measurement errors are not available and the impact of the structure of observations is much higher, each single hydraulic head measurement is weighted according to the time for which it is

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representative, divided by the standard deviation of all observations of the particular piezometer. Transport modelling

Transport simulations are carried out in order to show the plausibility of the concept of temporal variant leakage. Due to restricted data and travel times they are carried out only within a small area of the flow model domain (see Figure 2, around transect in the center of the area including the observation wells 3312 and 3313). The species 18O and temperature are modelled. 18O is an ideal tracer and data are available between 2002 and 2005. Temperature is modelled because time series are available since 2000. The transport model was set up with the following parameters: effective porosity of 0.22, aquifer bulk density of 1.820 g/cm3, aquifer heat capacity of cs = 800 J kg-1 K-1, water heat capacity of cw = 4184 J kg-1 K-1, and thermal diffusivity of 1.3 * 10-6 m2/s. Dispersivity is insensitive up to a length of 1 m and a larger dispersivity deteriorates the fit. In order to minimize mass balance error it is set to nil. Transport is simulated with MT3DMS (Zheng & Wang 1999) and the HMOC particle tracking scheme. 3.2.2.3

Results and Discussion Groundwater flow

The comparison of measured and simulated hydrographs of the observation well TEG050 (as a representative example) shows the general behaviour of the hydraulic model. This observation well is located far enough from the well field, so that switching of wells and effects of local aquifer configuration are mitigated. The boundaries are far enough, thus, simulated heads are sensitive to the model parameterization. The variations of hydraulic head are induced by pumping regime of the waterworks Tegel, principially of well field West.

Fig. 5: Measured and simulated piezometric heads (case 2 and 3) at observation well TEG050.

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The fit of all four cases appears acceptable; in Figure 5 comparison of measured and simulated results are shown for the cases 2 and 3. Comparing the objective function for TEG050, case 3 is the best fit, the goodness of case 2 and 4 is similar, and case1 is the worst representation of the observed groundwater dynamics. The ratio of 1.6 between the largest and smallest value of the objective function is lowest for observation well 3301. Daily measurements are included into the model, which has a weekly time discretization. Thus, the model can only be optimized to a mean curve through the daily fluctuations. Though observation well 3301 contributes between 40% (case 1) and 70% (case 3) to the objective function, it shall be emphasized, that parameters only change slightly if it is taken out from the objective function. This is a strong indication that the parameterization is physically based (Hill 1998). Leakage

The leakage coefficients are first approximatively calculated from in situ measurements, where the thickness of the clogging layer is assumed to be 10 cm (Wiese 2006). In Figure 6 measured and depth dependent leakage coefficients are depicted for the four cases to be studied. The depth dependency as well as the time variability of these coefficients is determined by inverse modelling.

Fig. 6: Measured and modelled leakage of the lake bed. Each point represents the mean value at a certain observation location. Measurements of Hoffmann (2006) have been carried out between March 2004 and February 2005, measurements of this study in June and July 2004. Modelled values are adapted to the hydraulic situation in June/July 2004.

In order to implement temporal variant leakage coefficients as well as easy communication with PEST, the MODFLOW2000 code has been modified. The resulting hydraulic heads are quite similar for both, case 2 and 3 (Fig. 5), though the parameterisation is quite different (Fig. 6). Under the premise of a linear temporal behaviour, the leakage is higher in greater depth. If the temporal behaviour is not forced to be linear, measurements indicate

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that the pattern is quite variable (Fig. 7) and the leakage is higher in shallow water (Fig. 6). A higher temporal resolution neither led to a considerably lower objective function nor resulted in a significantly different temporal behaviour.

Fig. 7: Temporal leakage for case 2 and 3 (left axis); the pumping rate (right axis) is the monthly average of well field West.

The leakage has revealed to be temporally variable. Potentiall, many mechanisms could cause the leakage to vary with time: Viscosity of water due to temperature effects, compression of lake bed by changing pressure head, clogging by suspended matter, chemical or bioclogging etc.

Fig. 8: Measured and simulated piezometric heads at observation well TEG050 with case 4 parameterization.

As show in Figure 7, for case 3 the leakage is correlated (R2=0.42) with the pumping rate and reacts with a small delay, but the observed hydraulic heads of the groundwater indicate an unsaturated zone for the shallower regions of Lake Tegel, which would cause the hydraulic independence of the

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infiltration to the groundwater table. If the thickness of the clogging layer is small in comparison to the hydraulic head differences, high infiltration rates could occur because an increased hydraulic gradient across the clogging layer increases infiltration more than proportional. Using a simple, not physical based function of the leakage depending on the thickness of the unsaturated zone, the resulting distribution is shown in Figure 6 (turquoise line).

The simulated hydraulic heads at observation well TEG050 are plotted in Figure 8. The application of case 4 instead of case 2 or case 3 improves the fit of observed and simulated hydraulic heads in general. The temporal dynamic coincides better, and also the arithmetic mean of hydraulic head in observation well 6053 between January 1998 and April 2002 of 28.84 m NN of case 4 is much closer to the observed mean of 28.81 m NN than case 3 with 29.23 m NN. The current parameterisation reproduces the most important temporal behaviour, and the reduction from 45 to 2 parameters is a significant improvement in parameter parsimony and solution uniqueness. Transport simulation

The results of transport model are obtained using the hydraulic model of case 3 and transport parameters described above. Since the model is only calibrated using hydraulic data, the goodness of the presented transport behaviour indicate the correctness of the flow field (see Fig. 9). Temperature is only shown for well 13. Only for temperature the inland boundary values are well known thus results are very important for abstraction wells. As one example, the resulting travel times between the infiltration zone and observation wells 3301 and 3302 are approximately 4 month.

Fig. 9: Selected results of transport modelling. 18O is shown for observation wells 3301, 3302, TEG371op, TEG371up, Well 12 and Well 13 for a period between 2002 and 2005. Temperature time series is presented for Well 13 for a perid between 2000 and 2005.

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Acknowledgement

This study was carried out within the NASRI (Natural and Artificial Systems for Recharge and Infiltration) project of the KompetenzZentrum Wasser Berlin. The authors thank Berliner Wasser Betriebe and Veolia Water for the financial support of this study. References BEAR, J. (1972): Dynamics of fluids in porous media. Dover Publ., New York. DOHERTY, J. (2003): PEST – Model independent parameter estimation user manual, Watermark Numerical Computing, 336 pp. DOUSSAN, C., TOMA, A., PARIS, B., POITEVIN, G, LEDOUX, E., DETAY, M. (1993): Coupled use of thermal and hydaulic data characterize river-groundwater exchange. J. Hydrol., 153, 215-229. FRITZ, B., RINCK-PFEIFFER, S., NÜTZMANN, G., HEINZMANN, B. (2004): Conservation of water resources in Berlin, Germany, through different re-use of water. In: Steenvorden, J., Endreny, Th. (eds.): Wasrewater re-use and groundwater quality. IAHS publ. 285, 48-52. GRISCHEK, T., SCHOENHEINZ, D., WORCH, E., HISCOCK, K. (2003): Bank filtration in Europe – an overview. In: Dillon. P. (eds.): Management of aquifer recharge for sustainability. Balkema, Lisse, 485-488. HARBAUGH, A. W., BANTA, E. R., HILL, M. C., MCDONALD, M. G. (2000): MODFLOW-2000,The U. S. Geological Survey modular groundwater model. Open-file report 00-92. HILL, M. C. (1998): Methods and guidelines for effective model calibration. U.S. Geological Survey Water Resources Investigations Report 98-4005, Denver, CO. HOLZBECHER, E., ENGELMANN, B., NÜTZMANN, G. (2006): The viscosity effect on infiltrating surface water. Hydrogeol. J. (under review). HUETTEL, M., ROY, H., PRECHT, E., EHRENHAUSS, S. (2003): Hydrodynamical impact on biogeochemical processes in aquatic sediments. Hydrobiologia, 494, 231-236. LIN, C., GREENWALD, D., BANIN, A. (2003): Temperature dependence of infiltration rate during large-scale water recharge into soils. Soil Sci. Soc. Am. J., 67, 487-493. MIETTINEN, I., VARTIAINEN, T., MARTIKAINEN, P. J. (1997): Microbial growth and assimilable organic carbon in Finnish drinking waters. Water Science Technol. 35, 301-306. SCHUBERT, J. (2002): Hydraulic aspects of riverbank filtrtaion – field studies. J. Hydrol., 266, 145-161. WEBTECH360 (2003): Processing Modflow Pro – Users Manual, Fairbanks, USA, 413 pp. WIESE, B. (2006): Spatially and temporally scaled inverse hydraulic modelling, multitracer transport modelling and interaction with geochemical processes at a highly transient bank filtration site. PhD thesis, Geographical Institut, HumboldtUniversity of Berlin, 233 pp. ZHENG, C., WANG, P. P. (1999): MT3DMS – a modular three-dimensional multispecies model for simulation of advection, dispersion and chemical reactions of contaminants in groundwater systems, Documentation and User’s Guide, Rep. SERDP-99-1, Vicksburg, M.S.

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G OLOSOV , S., K IRILLIN , G.

3.2.3 Modelling dissolved oxygen dynamics in icecovered shallow lakes Modellierung des dynamischen Sauerstoffverbrauchs in zugefrorenen Flachseen

Key words: water quality, anaerobic zone, thermal regime, shallow lakes Abstract

Based on the observational data from five freezing lakes located in Northwestern Russia and North America, the effect of the heat interaction between a water column and sediments on the formation, development, and duration of existence of anaerobic zones in ice-covered lakes is estimated. A simple one-dimensional model that describes the formation and development of the dissolved oxygen deficit in shallow ice-covered lakes is suggested. The model reproduces the main features of dissolved oxygen dynamics during the ice-covered period, that is, the vertical structure, the thickness and rate of an increase of the anaerobic zone in bottom layers. The model verification is performed against observational data. Results of verification show that the model adequately describes the dissolved oxygen dynamics in winter. The rates of DO consumption by bacterial plankton and by bottom sediments, depending on the heat transfer through the watersediment interface, are calculated. Received results allow predicting appearance of potentially dangerous anaerobic zones in shallow lakes and in separate lake areas in dependence on the thermal regime changes. Zusammenfassung

Auf der Datengrundlage von fünf Seen aus dem Nordwesten Russlands und dem Norden Amerikas soll abgeschätzt werden, welche Rolle der Wärmeaustausch zwischen Wassersäule und Sediment bei der Bildung und der räumlichen und zeitlichen Entwicklung anaerober Zonen in eisbedeckten Flachseen spielt. Dafür wird ein einfaches 1-D-Modell vorgeschlagen, mit Hilfe dessen die Entstehung und der Verlauf eines Mangels an gelöstem Sauerstoff unter Eis beschrieben werden kann. Das Modell gibt die wesentlichen Merkmale des dynamischen Verhaltens von gelöstem Sauerstoff während der Eisbedeckung wieder, nämlich die Dicke der anaeroben Schicht, ihre vertikale Struktur und die Rate, mit der sie sich ausdehnt. Der Vergleich der Modellsimulationen mit den Messdaten zeigt, daß die Dynamik des gelösten Sauerstoffs im Winter vom Modell adequat widergespiegelt wird. Die vom Wärmeaustausch an der Wasser-SedimentGrenze abhängigen Raten, mit denen der gelöste Sauerstoff von bakteriellem Plankton und dem Sediment verbraucht wird, stellt das Modell ebenfalls bereit. Die erzielten Ergebnisse erlauben vorauszusagen, ob bei einem Wandel des thermischen Regimes in Flachseen (oder deren Teilen) potenziell gefährliche, anaerobe Zonen auftreten können.

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3.2.3.1

Introduction

The water quality in freshwater reservoirs in many respects is determined by the content of dissolved oxygen (DO). In lakes with high DO concentration, the bacterial destruction of organic matter is accompanied by extraction of carbon dioxide, which is harmless for hydrocoles, into water. A decrease of the DO concentration or its complete absence leads to the activation of anaerobic processes, which usually occur with evolving such deoxidized gases as methane (CH4), hydrogen sulphide (H2S), and ammonia (NH3). Those are capable to not only worsen the water quality, but also to be toxic (especially it concerns H2S). The onset and continuous existence of the anaerobic zone in lakes leads to such negative consequences as fish kill, loss of benthic organisms, changes in the trophic chains of water ecosystems, etc. A DO deficit in shallow lakes occurs in absence of water aeration. The formation of anaerobic zones in lakes may take place during the open-water period and in winter. The duration of such phenomenon in the former case is rather short as occasional wind mixing of water column from top to bottom provides aeration of the bottom layers. The most dramatic situation may occur in ice-covered lakes located in moderate and high latitudes because the factors defining a DO regime in a shallow ice-covered lake essentially differ from those during the open-water period. First, it is related to main sources of oxygen flow. In winter, the ice cover excludes a gas exchange with atmosphere. Besides, amount of solar radiation penetrating into water becomes negligible that leads to a drastic decrease of photosynthetic intensity. Thus, main sources of oxygen supply practically disappear, and only consumption of oxygen by bacterial plankton in the process of organic matter decomposition together with its absorption by bottom sediments control the DO content in a lake (Hargrave 1972). The rate of DO consumption in ice-covered lakes as a rule depends on a set of biological and hydrophysical factors. Usually, the biochemical factors, such as vital functions of the different organisms (including bacterial plankton) within the benthic community, the concentration of the organic matter and DO in the near-bottom layers, are considered as the main parameters responsible for the formation of the oxygen depletion in icecovered lakes (Hutchinson 1957; Hargrave 1972; Mathias and Barica 1980; Cornett and Rigler 1987). On the other hand, it is well known that the life activity of the bacterial plankton, which is the main consumer of DO, is strongly dependent on the water temperature (Boylen and Brock 1973; Welch et al. 1976; Charlton 1980; Kovaleva et al. 2003). In spite of this fact, it is commonly assumed that as long as the temperature in ice-covered lakes is low and varies in a very narrow range (from 0 to 4-5°C), its effect on the bacterial activity is not great and DO winter depletion depends only on the concentration of organic matter in water column. Nevertheless, in the frames of the present study the efforts to evaluate the role of the temperature in the development of DO winter depletion in ice-covered lakes were undertaken. As it will be shown below, in some cases

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the so-called “effect of under-ice warming” can lead to considerable strengthening in the development of anoxic conditions in ice-covered lakes. 3.2.3.2

Material and Methods

Field data collected in three Russian, one American, and one Canadian freezing lake were taken as the empirical material to perform the study. Russian and American lakes are natural water-bodies of different trophic state. Russian lakes Chainoe, Krasnoe, and Vendyurskoe are classified as mesotrophic. American Lake Alequash belongs to the eutrophic type whereas Canadian Lake Midnapore is an artificial urban water body of mesotrophic type located in Calgary (for details see Golosov et al. 2007). The phenomenon of winter DO depletion is intrinsic to Lake Allequash in the same way as for the Russian lakes (often to the point of full DO disappearance). In Lake Midnapore appearance of DO depletion is irregular and there were detected no cases of full DO consumption (Meding 2000). All data from Russian, American and Canadian lakes represents the DO and water temperature vertical distributions from top to bottom of the water column, measured in different dates from the beginning to the end of icecovered periods. Except Lake Midnapore, the thermal regime of the lakes in consideration is similar, including the under-ice warming of the water column due to heat flux from the sediments. The near bottom temperature varies from 0.5-1.0°C in the beginning of the ice-covered period to 4-5°C in the end. The data from Russian lakes and Lake Alequash were used to derive parameterizations of the model. These data were analyzed and processed in terms of the time dependent relations between the values of the DO deficit and temperature. Obtained functional relations were used to estimate the rates of the total DO consumption in lakes in dependence on the water temperature. The model verification was performed against the most detailed data from Lake Vendyurskoe and data from Lake Midnapore as the independent lake. Finally, the derived results were used in numerical experiments on studying the formation and development of the anoxic conditions in Lake Vendyurskoe. 3.2.3.3

Empirical verification of the model parameterisations

The model considers the DO vertical distribution within a ‘water-sediment’ system for the three most common cases (see Fig.1 a, b, c), that are: 1) the anoxic zone in a bottom water layer is absent and oxidizing conditions in the upper layer of bottom sediments prevail; 2) the DO concentration in the bottom layer is close to zero, the oxidized layer in bottom sediments is absent; and 3) the DO in the near-bottom layer is absent, and the anoxic zone starts to develop from bottom towards top of the water column. It is evidently from the field data, that the temporal variability of DO concentration in the vicinity of ice is lower than that in bottom layers for one order of magnitude at least. Therefore, in the frames of the model the DO

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Fig. 1 Evolution of the DO vertical profile in an ice-covered lake during the winter (see text for further explanation).

concentration at water-ice boundary can be assumed as constant during the ice period. A detailed model description of the formation and development of DO depletion in shallow ice-covered lakes, which uses in analogy to thermal regime modeling (Mironov et al. 1991; Kirillin 2003; Golosov et al. 2003) the socalled self-similarity approach can be found in Golosov et al. (2005). In the framework of this approach, invariability of the shapes of the vertical DO profiles in a water column and the upper layer of sediments is assumed.

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The Results of verification of the model are mentioned here only briefly. A detailed presentation was given in (Golosov et al. 2007). Measured and calculated vertical DO profiles of Lake Vendyurskoe corresponding to different dates of the winter 2001-02 were compared for the water column (Fig. 2a. in Golosov et al. 2007) and for the upper oxidized layer of the sediments (Fig. 2b in Golosov et al. 2007). Because the authors do not possess own observational data on the vertical distribution of DO in sediments (which can be received only with use of special micro-profilers) data of natural and laboratory studies performed by other investigators (Archer and Devol 1992; Jorgensson and Revsbech 1985; Lorke et al. 2003) were used in the sediment comparison. Results of calculations show that the model describes the temporal variability of the vertical DO profiles, from the ice cover formation to the end of its existence, fairly well. This means that the representation of the water DO profile assumed in the model, is quite realistic. 3.2.3.4

Results of the model runs and Discussion

The verification of the model was performed against the field data collected in two lakes, namely Lake Vendyurskoe (Russia) and Lake Midnapore (Canada). Lake Midnapore was chosen for the model verification as independent object since data from this lake were not used in deriving the model parameterizations. Among aforementioned field data from different lakes the most detailed data were obtained in Lake Vendyurskoe in 2001-02. That was the main reason to choose Lake Vendyurskoe for studying the peculiarities of the winter DO depletion. As the first step of the model verification, the temporal dynamics of DO concentration in Lake Vendyurskoe was calculated. To reveal the peculiarities of the phenomenon under study, two locations with different depths were chosen, namely St. 9 and St. 16 of 11.5 m and 5 m depth, respectively. The differences between the stations consist not only in the depths and places of location, but mainly in the thermal regime during the ice-covered period Thus, the near-bottom temperature at St. 16 varies from 0.9°C in the middle of November (beginning of ice formation) to 2.5°C in the middle of April. The corresponding variability of temperature at St. 9 covers the range from 1.2°C to 4.6°C. The effect of the temperature on the formation of DO depletion was studied under different conditions. Firstly, we calculated the DO deficit and the thickness of the anoxic zone using the real temperature conditions observed during the surveys. Results of these runs are presented in Fig. 2 a, b, c. The distance between both stations does not exceed one kilometer, but the oxygen conditions differ strikingly. The storage of DO in bottom layers at the deeper station became negligible no longer than in a half of month after the ice formation (see Fig. 2a,b), whereas at St. 16 the more or less essential deficit of DO appeared just in the middle of April (see Fig. 2c). At St. 9, the completely anoxic zone started developing after full DO consumption and reached the thickness of 1.5 m in the end of the winter.

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Fig. 2: Evolution of the DO concentration and of the anoxic zone thickness H in Lake Vendyurskoe (a, b, c) and in Lake Midnapore (d). Diamonds and squares are the DO concentrations measured under the ice cover and in the near-bottom water correspondingly. Triangles mark the measured thickness of the anoxic zone. Dashed and solid lines correspond to the model DO concentrations under the ice and in the near-bottom water.

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At the St. 16, the anoxic zone did not appear at all. The values of the rate of DO consumption for the under ice and near bottom zones were the same for the both stations. Thus, the model runs differ from each other only by the courses of temperature. In other words, the difference in peculiarities of thermal regime between two stations can be responsible for the features of formation of DO depletion within lake. In addition to the good agreement between measured and calculated near bottom DO concentration (Fig. 2a, c), it should be noted that the variability of DO concentration in the vicinity of ice actually is very small, e.g. the corresponding assumption accepted at the model formulation is correct. The next set of the model runs was intended to reproduce the winter course of DO concentration in Canadian Lake Midnapore. Before discussion of the results of simulations, it is essential to note, that the thermal regime of the lake considerably differs from that of the other lakes. The effect of under-ice warming is not pronounced in this lake. The near bottom temperature is almost constant during the whole winter and remains close to the value of temperature of water maximal density, e.g. 4“C. It means that the limiting effect of the low water temperature on the rate of formation of DO depletion in this case should be less than that in the case of Lake Vendyurskoe. Results of the model application to Lake Midnapore presented in Fig. 2d confirm that statement. A decrease of the DO concentration in the nearbottom area takes place at essentially higher rate than that at St. 16 in Lake Vendyurskoe though both sites are of the same depth. As a result, the DO concentration in Lake Midnapore reaches its minimal values in 90 days after the ice-covered period started, whereas in Lake Vendyurskoe the same values of DO concentration were observed in 150 days (Fig. 2c). The following runs of the model were intended to reveal the effect of the shift of thermal regime on the formation of DO depletion. The under-ice DO regime for St. 9 was calculated using the temperature measured at the “cold” St. 16, and vice versa, the “warm” winter conditions for St. 16 were simulated with temperature data obtained at the St. 9. Results of simulations are presented in Fig. 3. The model experiments show a rather strong dependence between the DO and thermal regimes of lakes (or their single areas). Under conditions of “cold” winter, the full consumption of DO at deep St. 9 has been developed in two months after the ice period began. Respectively, the anoxic zone started to develop later comparing to the “warm” case and reached essentially lower thickness in the end of winter. These results were quite expected. A more dramatic situation was revealed by simulations for shallow St. 16. The shift in temperature entailed serious worsening in the DO regime. The fully anoxic zone is observed already in 40 days after the ice formation. The rate of its development reached 0.5 cm d-1. It is not as high as at St. 9, but notice that in the case of “cold” winter there was no anoxic zone at this station at all.

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Fig. 3: Results of numerical experiments: a, b – evolution of the near bottom DO concentration and the thickness of the anaerobic zone at St. 9 in case of “cold” winter; c, d – the same at the St. 16 in case of “warm” winter.

The results of numerical experiments performed in the present study allow formulating some conclusions on the nature and the reasons of the winter DO depletion in shallow ice-covered lakes. In lakes, where the concentration of the organic matter is not a limiting factor (the cases of mesotrophic and eutrophic lakes), the winter deficit can be formed due to peculiarities of the lake winter thermal regime. In turn, the latter is affected by warming/cooling conditions during the previous summer/autumn and by the heat interaction between a water column and sediments. So, it means that

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the winter DO depletion in many respects depends not only on the biochemical processes in lakes and duration of the ice-covered period, but can be determined by the physical factors acting long before the ice formation in a lake. Actually, as soon as the thermal regime of ice-covered lake plays an important role in formation of DO winter depletion, all factors affecting the heat storage of sediments, can straightly or indirectly influence on the rate of formation and duration of anoxic conditions in a lake. First of all, it concerns to the summer mixing conditions and duration of “autumnwinter” cooling of a lake. The heat accumulation by sediments under neutral or weak density stratification is much more efficient compared to the conditions of stably stratified water column. In summer, frequent turbulent mixing of the water column from top to bottom provides the effective heat penetration from warm upper layers down to the near-bottom zone. As a result, sediments accumulate a considerable amount of heat. And vice versa, the existence of the stable density stratification in a water column prevents the downward heat penetration. The heat exchange between near-bottom water and sediments is depressed in this case, and the heat content of sediments is small. The duration of the “autumn-winter” cooling, following after summer warming, also influences on the sediments heat content in the beginning of ice-covered period. In a case of fleeting and very intensive water column cooling in autumn, sediments retain considerable heat content to the time of ice formation. That leads to the rapid under-ice water warming after the freeze-up and, as a consequence, to the rapid formation of DO depletion. On the contrary, in a case of long “autumn-winter” cooling, sediments get cold enough and its heat content is too small to provide a reasonable increase of water temperature during the winter. In this case the sediments are not able to increase the near-bottom temperature considerably, and the low water temperature can prevent the fast development of the DO depletion. Some logical deduction can be done concerning the effect of the expected global warming on the DO regime of ice-covered lakes. Taking into account the aforementioned results of the model runs, the warming may play an essentially negative role in the deterioration of the DO regime in freezing lakes. The expected increase in winter near-bottom temperature can lead to a more frequent formation of the anoxic zones in lakes. Moreover, one can expect that the time and spatial scales of those events would increase considerably. Acknowledgement

The present study is supported by European Commission (project INTAS 01-2132), the Swedish Institute (VISBY Programme), Ǻke och Greta Lisshed Foundation, Sweden, the Russian Academy of Sciences, and the German Foundation of the Basic Research (DFG, Project KI-853/3-1 in frames of the program „AQUASHIFT“). The support is gratefully acknowledged. Authors express their admiration and gratitude to the field research team of the Northern Water Problems Institute for their heroic efforts at collecting field data during winter field campaigns.

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References ARCHER D, DEVOL A. 1992. Benthic oxygen fluxes on the Washington shelf and slope: A comparison of in situ microelectrode and chamber flux measurements. Limnol. Oceanogr. 37: 614-629. BOYLEN C, BROCK, T. 1973. Bacterial decomposition processes in Lake Wingra sediments during winter. Limnol. Oceanog. 18(4): 628-634. CHARLTON M. 1980. Hypolimnion oxygen consumption in lakes: discussion of productivity and morphometry effects. Can. J. Fish. Aquat. Sci. 37: 1531-1539. CORNETT R , RIGLER F. 1987. Vertical transport of oxygen into the hypolimnion of lakes. Can. J. Fish. Aquat. Sci. 44: 852-858. GOLOSOV S, ZVEREV I, TERZHEVIK A. 2003. Thermal Structure and Heat Exchange in Ice-Water Column-Sediment System. In: TERZHEVIK, A.(ED) Proc. 7th Int. Symp. Physical Processes in Natural Waters, July 2003, Petrozavodsk, Russia: 17 28 GOLOSOV S, SHIPUNOVA E, MAHER OA, TERZHEVIK A, ZDOROVENNOVA G. 2005. Physical background of oxygen depletion development in ice-covered lakes. In: FOLKARD A, JONES I (EDS). Proc 9th Europ Workshop on Physical Processes in Natural Waters, September 2005, Lancaster University, UK, 229–237. GOLOSOV S, MAHER OA., SCHIPUNOVA E, TERZHEVIK A., ZDOROVENNOVA G, KIRILLIN G.2007. Physical background of the development of oxygen depletion in ice-covered lakes. Oecologia, 151: 331-340 HARGRAVE B. 1972. A comparison of sediment oxygen uptake, hypolimnetic oxygen deficit and primary production in Lake Esrom, DK. Verh. Int. Ver. Limnol. 18: 134-139. HUTCHINSON G. 1957. A treatise on limnology. Vol I. J.Wiley & Son, NY, 1015 p. JORGENSEN B, REVSBECH N. 1985. Diffusive boundary layers and the oxygen uptake of sediments and detritus. Limnol. Oceanogr. 30: 111-122. KIRILLIN G. 2003. Modeling of the Shallow Lake Response to Climate Variability In: TERZHEVIK, A (ED). Proc. 7th Int. Symp. Physical Processes in Natural Waters, July 2003, Petrozavodsk, Russia: 144-148. KOVALEVA N, MEDIENTZ V, GAZETOV E. 2003. Influence of temperature and oxygen content on the intensity of the organic matter decay in Black Sea. Gidrobiologicheskiy Zhurnal (J. of Hydrobiology) 39(4): 34-40. (in Russian) LORKE A, MULLER B, MAERKI M, WUEST A. 2003. Breathing sediments: The control of diffusive transport across the sediment-water interface by periodic boundarylayer turbulence. Limnol. Oceanogr. 48(6): 2077-2085. MATHIAS J, BARICA J. 1980. Factors controlling oxygen depletion in ice-covered lakes. Can. J. Fish. Aquat. Sci. 37: 185-194. MEDING M. 2000. Structure and function in shallow prairie lakes: macrophytes and winter anoxia. Master thesis, University of Calgary: 124 p MIRONOV D, GOLOSOV S, ZILITINKEVICH S, KREIMAN K, TERZHEVIK A. 1991. Seasonal changes of temperature and mixing conditions in a lake. In: ZILITINKEVICH S (ED). Modelling Air-Lake Interaction. Physical Background. Springer: 74-90. WELCH H, DILLON P, SREEDHARAN A. 1976. Factors affecting winter respiration in Ontario lakes. J. Fish. Res. Board Can. 33: 1809-1815.

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3.3 Research Topic 3 Forschungsschwerpunkt 3

Adaptation, plasticity and dynamics of communities Adaptation, Plastizität und Dynamik von Biozönosen

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G LOESS , S., H UPFER , M., R ATERING , S., G ROSSART , H.-P.

3.3.1 Detection and phylogenetic characterization of polyphosphate accumulating bacteria in lake sediments Nachweis und phylogenetische Charakterisierung von Polyphosphatakkumulierenden Bakterien in Seesedimenten

Key words: polyphosphate, sediment, bacteria, polyphosphate accumulating bacteria (PAO), single cell separation, laser microdissection, DGGE Abstract

The direct contribution of microorganisms to the mobilization and immobilization of phosphorus (P) in aquatic sediments has been controversially discussed since more than one decade. Polyphosphate (PolyP) storage is an universal ability of many microorganisms and has been technically optimized in wastewater treatment plants (WWTP) by providing conditions for an enhanced biological phosphorus removal (EBPR). Poly-P accumulating organisms (PAO) in sediments, thus, might be of high ecological importance. PAO in sediments are able to insert P into the benthic food chain and affect the permanent P mineral deposition by physiologically inducing rapid P release. Although several studies indicate that Poly-P substantially contributes to total P in the uppermost sediment layer, its origin as well as the microorganisms and mechanisms involved in Poly-P storage and cycling are unknown. Therefore, we have screened sediments from eight lakes different in trophy and limnological features for the presence of PAO. We have used denaturing gradient gel electrophoresis (DGGE) with a set of primers specific for bacteria closely related to the genus Rhodocyclus, belonging to the most popular PAOs in WWTP with EBPR. Our screening shows that members of the genus Rhodocyclus are present in all studied sediments. However, subsequent quantification of these PAO by fluorescence in situ hybridization (CARD-FISH) with oligonucleotide probes specific for the Rhodocyclus-PAO revealed that they only contribute to