Der Einfluss des Nahrungsangebots auf Salpa thompsoni Foxton (Thaliacea, Tunicata) und Folgen für biogeochemische Stoffflüsse im Südpolarmeer
Final Report Abstract
In the iron fertilizarion experiment EIFEX in the Southern Ocean in February - March 2004, we could follow the effect of a stimulated phytoplankton bloom on the distribution and population structure of salps. In the first two weeks of the experiment, the area was populated by ca 600 Ind 1000 m^-3 of Salpa thompsoni. In contrast lo other zooplankton such as copepods, they showed a negative response towards the developing bloom and their density decreased inside the patch. This negative response was enhanced by the salps' life cycle with a declining salp population towards the end of the summer season with only occasional salp catches of low biomass not only in areas with high but also with low phytoplankton concentrarions. Yet, the salps did not show an immediate negative response towards high particle concentrations as presumed in the literature and were actively feeding in vivo (from gut content measurements) and in vitro (in feeding experiments) in both areas. Biogeographical comparison of salp population structure, development and feeding will be possible with the salp population at the Antarctic Peninsula in February 2006. In the Lazarev Sea area, the Antarctic Ihlea racovitzai proliferated even in winter time and showed surprisingly high gut contents even at extreme low phytoplankton concentrations under the ice whereas S. thompsoni truly reached its extension limits in the higher Antarctic latitudes with low abundances and low feeding activity. The results were and will be presented not only in scientific literature and on scientific conferences as oral presentations and posters, but were also made available for public in ways as listed below: A public lecture was presented on 24. November 2005, Haus der Wissenschaft, Bremen, by Bathmann entitled „Eisendüngung im Südpolarmeer - Ein Beispiel angewandter Klimaforschung". Print media reported on our research in a press report by SPIEGEL ONLINE - Nachrichten entitled "Mini-Quallen entziehen Atmosphäre Kohlendioxid" (http://www.spiegel.de/wissenschaft/erde/0.1518.424766.00.html). German radio stations (Deutschlandfunk, Radio Bremen) interviewed Bathmann and reported especially during and shortly after each of the Polarstem Antarctic expeditions. The main outcome of the research is made public available on the following Internet pages: - http://www.divediscover.whoi.edu/expedition10/index.html (Educational project for US American schools (NBF project)) On the AWI web pages a summary of the project is presented: - http://www.awi.de/en/research/research divisions/biosciences/biological oceanograp hy/proiects/lakris/ - http://www.awi.de/en/research/research divisions/biosciences/biologicaLoceanograp hv/research_themes/zooplankton/salp_ecologv_in_the_southern_ocean/
Publications
- (2004). Response of the pelagic tunicate Salpa thompsoni to an iron induced phytoplankton bloom in the Southern Ocean Frontal Zone (EIFEX). 22. Internationale Polartagung der Deutschen Gesellschaft für Polarforschung, September 18-24, Jena, Germany
Harbou, L., Bathmann, U., Peeken, I., Jansen, S., Krägefsky, S.
- (2004). Zooplankton contribution to matter export after iron fertilization in the Southern Ocean. SCAR Open science conference/Antarctica and the Southern Ocean in the global system, July 25-31, Bremen, Germany
Bathmann, U., Krägefsky, S., Strass, V., Smetacek, V.
- (2005). Ecological and biogeochemical response of Antarctic ecosystems to iron fertilization and implications on global carbon cycle. Ocean and Polar Research, 27(2), 231-235
Bathmann U.
- (2005). Ökologische und Biogeochemische Reaktionen antarktischer Systeme auf Eisendüngung und Implikationen für globale Stoffkreisläufe. Kolloquium Univ. Oldenburg, January 26th, Oldenburg, Germany
Bathmann, U.
- (2006). Effect of in situ iron fertilisation during contrasting seasons - comparison between EisenEx and EIFEX. Ocean Sciences Meeting, February 20-24, Honolulu, USA
Peeken, I., Hoffmann, L., Assmy, P., Bathmann, U., Croot, P., Harbou von, L., Henjes, J., Jansen, S., Krägefsky, S., Lochte, K., Sachs, O., Sauter, E.
- (2006). Global change in Antarctic pelagic ecosystems: Effects of bottom-up regulation (iron fertilisation) and top-down control (krill-salp interaction) on plankton biomass. 36th Annual Conference. Gesellschaft für Ökologie. September 11-15, Bremen, Germany
Bathmann, U., et al.
- (2007). Biological Research in Antarctica, two examples for international co-operation: iron fertilization and krill overwintering studies. Korean-German Workshop on Polar and Marine Sciences, May 22-25, Alfred Wegner Institute for Polar and Marine Research, Bremerhaven, Germany
Bathmann, U.
- (2008). Antarctic Pelagic Tunicates: Could salps be an attractive prey? SCAR/L\SC IPY, Open Science Conference, July 8-11, St. Petersburg, Russia
Pakhomov, E. A., Dubischar, C. D., Hunt, B. P. V., Gumey, L., Siegel, V., Bathmann, U.
- (2008). European projects on global change and its impact on marine ecosystems in the Southern Ocean. European Conference on "Global Change and Marine Ecosystems", November 25-27, Rome, Italy
Bathmann, U.
- (2008). Polar ocean ecosystems and changing climate. SCAR/IASC IPY Open Science Conference, July 8-11, St. Petersburg, Russia
Bathmann, U.
- (2008). Seasonal inertia of macrozooplankton communities in the Lazarev Sea. SCAR/IASC IPY, Open Science Conference, July 8-11, St. Petersburg, Russia
Hunt, B. P. v., Pakhomov, E. A., Siegel, V., Bathmann, U.
- (2008). Trophic structure & interactions; High Biomass Low Export systems vs HNLC regions. EurOceans workshop. May 28-30, Vrije Universiteit Brussel, Belgium
Bathmann, U.
