Influencia de los factores bióticos y abióticos sobre la abundancia y biomasa de copépodos harpacticoídeos en una cala poco profunda de la Antártida

This study presents data of the first investigation on benthic harpacticoid copepods in Potter Cove, King George Island, Antarctica (62°14’S, 58°40’W) with special emphasis on spatial distribution and relation to environmental factors. In addition to the individual numbers that are normally given, the biovolume of the meiobenthic copepods was measured. It showed great variety due to changes in abundance and habitat preferences of the different species along the two studied transects in the inner cove and at the cove entrance. The distribution of the two species Pseudotachidius jubanyensis and Scottopsyllus (S.) praecipuus was studied in detail; their body volumes are given for developmental stages and adults, and their importance for the total biovolume at the different stations is discussed. Statistical analyses (Spearman rank, canonical correspondence analysis) indicate that the biovolume of harpacticoid copepods was related more to total organic matter than to the carbon:nitrogen ratio and chloroplastic equivalents or even grain size and depth. While P. jubanyensis was strongly connected to depth and to a lesser extent to small grain sizes, S. (S.) praecipuus showed a preference for sites with low chloroplastic equivalent values, but neither of them was related to total organic matter.El presente estudio facilita los primeros datos sobre la distribución espacial de los copépodos harpacticoídeos bentónicos en la Caleta Potter, Isla Rey Jorge, Antártida (62°14’S, 58°40’W) y su relación con factores ambientales. Además del cálculo de abundancias se midió el biovolumen de los copépodos del meiobentos. Se detectó una variabilidad bastante elevada del biovolumen debido a las diferentes preferencias ecológicas de las especies a lo largo de los dos transectos muestreados, uno en la entrada de la cala y otro en su interior. La distribución de dos de las espécies encontradas, Pseudotachidius jubanyensis y Scottopsyllus (S.) praecipuus, fué estudiada en detalle. Se presentan datos del biovolumen de los diferentes estadios ontogenéticos y de los adultos de estas dos especies y se discute su importancia para el biovolumen total en las diferentes estaciones muestreadas. Análisis estadísticos (Spearman rank, análisis canónico de correspondencias) indican que el biovolumen de los copépodos harpacticoídeos está mejor correlacionado con el contenido orgánico total que con la relación carbono:nitrógeno y equivalentes de pigmentos cloroplásticos o incluso con parámetros granulométricos y profundidad. P. jubanyensis parece estar relacionado con la profundidad y, en menor medida, con sedimento de grano fino, mientras que S. (S.) praecipuus mostró preferencia por estaciónes con valores bajos de equivalentes de pigmentos cloroplásticos, pero ninguna de las especies está relacionada con el contenido total de materia orgánica

Ecosystem functions in the Southern Ocean: Sea ice means life at the seafloor

Gemeinsam mit unseren Student/-innen und Kooperationspartner/-innen arbeiten wir daran, die Ökosystemfunktionen der Weichböden auf den Schelfgebieten der Antarktis besser zu verstehen. Dafür haben wir an drei Expeditionen mit FS POLARSTERN teilgenommen und Sedimentproben vom Meeresboden in Kühlcontainern an Bord experimentell untersucht. Sauerstoffverbrauch und Remineralisierung sind Funktionen der Gemeinschaften von Lebewesen im Sediment. Als Stoffwechselendprodukte setzen sie Nährstoffe frei und sorgen dafür, dass der Kreislauf von Produktion und Abbau weiterläuft. Dabei spielt die Versorgung mit organischem Material aus den oberen lichtdurchfluteten Zonen des Ozeans eine entscheidende Rolle. Und diese Versorgung ist maßgeblich von der Eisbedeckung abhängig.Together with our students and cooperation partners we are working on a better understanding of the ecosystem functions of soft bottoms on the Antarctic shelf. Therefore, we participated in three expeditions with RV POLARSTERN and experimentally studied sediment samples from the seafloor in reefer containers on board. Oxygen consumption and remineralization are functions of communities of organisms in the sediment. They release nutrients as metabolic end products and ensure that the cycle of production and decomposition continues. The supply of organic material from the photic zone of the ocean plays a crucial role in this process. And this supply largely depends on the sea-ice cover

A new pelagic Alteutha (Copepoda: Harpacticoida) from Potter Cove, King George Island, Antarctica - Description, ecology and information on its year round distribution

A new harpacticoid copepod species was found during a year round plankton survey in a shallow Antarctic bay. Both the dominant Calanoida and Cyclopoida and the often neglected Harpacticoida, their abundances in relation to sea-ice formation and decline in presence of Euphausia superba are regarded, in this study. Alteutha potter sp. n. (Peltidiidae) was collected in Potter Cove, King George Island, Antarctica. While its geographical region occurrence and planktonic life style are comparable to many of its congeners, morphological characters such as shape and setation of the maxilliped and the almost complete fusion of the baseoendopod and the exopod of the fifth leg in the female are described for the first time for this genus. Morphological peculiarities such as the lack, the deformation or fusion of setae on only one body side have been detected in several specimens. This copepod species is obviously sea-ice related. Its abundances in the plankton reached a maximum under the winter sea-ice. The year round population structure did not show very high variability whereas ovigerous females mostly occurred in spring and summer. Assuming different possible ecological strategies and environmental temperatures generation times between 46 and 77 days are calculated for A. potter sp. n.Fil: Veit-Köhler, Gritta. Senckenberg Gesellschaft Für Naturforschung; AlemaniaFil: Fuentes, Verónica Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentina. Universidad de Buenos Aires; Argentina. Alfred-wegener-institut Helmholtz-zentrum Für Polar- Und Meeresforschung

Biodiversity in the Southern Ocean: From the shelf to the deep sea

Die abyssale Tiefsee der Antarktis wurde seit 2002 mit der Reihe der ANDEEP-Expeditionen untersucht. Die Fauna der Antarktischen Tiefsee ist sehr divers. Viele unbekannte Tierarten wurden entdeckt, Verbreitungsareale angepasst und systematische Zusammenhänge neu definiert. Tiefseearten kommen in der Antarktis auch auf dem Schelf vor, weil dieser tiefer liegt als der anderer Kontinente. Unter dem Schelfeis herrschen Bedingungen ähnlich wie in der Tiefsee, weshalb typische Tiefseegemeinschaften und -arten auch in diesen Regionen vorkommen.The abyssal deep sea of Antarctica has been studied with a series of ANDEEP expeditions since 2002. The fauna of the Antarctic deep sea is very diverse. Many unknown species have been discovered, distribution ranges adapted and systematic relationships redefined. Deep-sea species also occur on the Antarctic shelf because it is deeper than that of other continents. Conditions under ice shelves are similar to those in the deep sea, which is why typical deep-sea communities and species also occur in these regions