Description: The herbivorous Antarctic copepod Calanoides acutus overwinters inactively in a resting stage (diapause) at depths below 500 m. It is assumed that during diapause C. acutus is neutrally buoyant in order to retain energy reserves otherwise depleted by swimming activities. However, so far, no experimental observations on its buoyancy have been reported and our knowledge of buoyancy regulation mechanisms is incomplete. In the present study, species-specific differences in buoyancy were assessed visually. Observations were made of specimens from the diapausing cohort of C. acutus and compared to another herbivorous copepod Calanus propinquus, which overwinters actively feeding in the upper water layers. Freshly caught copepods were anaesthetized in a 3-amino-benzoic acid ethyl ester (MS222) in seawater solution in order to exclude the influence of swimming movements on buoyancy control. It was shown that C. propinquus was negatively buoyant, whereas diapausing C. acutus remained neutrally buoyant. This is the first record that neutral buoyancy in diapausing copepods is maintained by the biochemical body composition without the additional need of swimming movements.

Description: Das Pelagial ist der Lebensraum des freien Wassers mit allem, was darin schwimmt und driftet, vom winzigen Bakterioplankton über Phyto-, Zooplankton und Fische bis hin zu den den riesigen Walen. In welchen Bereichen und Tiefen leben die unterschiedlichen Organismen? Horizontale und vertikale, tages- und jahreszeitliche Wanderungen sowie die Wechselwirkungen zwischen den unterschiedlichen Organismengruppen und ihre Rolle im Nahrungsgefüge werden erläutert.

Description: Im Teil Zooplankton wird das breite und vielfältige Spektrum von Organismen des Holoplanktons von einzelligen Protisten bis zu metergroßen Quallen vorgestellt. Kurz wird auf das Vorkommen und die Ernährung der verschiedenen Organismengruppen eingegangen, etwas ausführlicher bei den häufigsten Gruppen der Metazoen, den Krebsen (Crustaceen), Manteltieren (Tunicaten) und Nesseltieren (Cnidariern).

Description: Together with Coral reefs and mangrove forests, seagrass meadows rank amongst the most important ecosystem components of tropical coastlines. The highly productive seagrasses support large biomasses of fishes and invertebrates, and are the preferred food item of iconic endangered species like green turtles and dugongs. Southeast Asia has the greatest diversity of seagrasses worldwide, and a substantial part of the global seagrass area. In spite of that, seagrasses in the region remain poorly studied. Research conducted in the Spermonde archipelago by scientists of the AWI in collaboration with representatives of Hasanuddin University Makassar aimed to fill some of the knowledge gaps on Southeast Asian seagrass ecosystems. In the first phase of the project the impact of seaweed farming on the productivity of the seagrass meadow below was adressed. The second focus was on the ecological role of synaptid holothurians, burrowing axiid shrimp and siganid fishes in the meadows. The biodiversity of gobiid fishes and plankton was also studied. In the second phase the main focus was on seagrass distribution, the impact of water motion and water depth on the composition of multispecies meadows, the controlling effect of callianassid shrimp and the diversity and diet of fish communities. Pinnid bivalves, macrobenthos diversity and plankton processes were the subject of further studies. In the third phase an in-situ carbon dioxide enrichment experiment was conducted, and the magnitude and fate of river inputs into the Spermonde lagoon was measured. In all three phases, capacity building was done through jointly supervised final theses and lectures in the “Marine Ecology Special Training Course”. Seventeen German and ten Indonesian students wrote their thesis within the project. A total of four PhD, 15 master and eight bachelor theses were completed.

Description: This data collection originates from the efforts of Sigrid Schnack-Schiel (1946–2016), a zooplankton ecologist with great expertise in life cycle strategies of Antarctic calanoid copepods, who also investigated zooplankton communities in tropical and subtropical marine environments. Here, we present 33 data sets with abundances of planktonic copepods from 20 expeditions to the Southern Ocean (Weddell Sea, Scotia Sea, Amundsen Sea, Bellingshausen Sea, Antarctic Peninsula), one expedition to the Magellan region, one latitudinal transect in the eastern Atlantic Ocean, one expedition to the Great Meteor Bank, and one expedition to the northern Red Sea and Gulf of Aqaba as part of her scientific legacy. A total of 349 stations from 1980 to 2005 were archived. During most expeditions depth-stratified samples were taken with a Hydrobios multinet with five or nine nets, thus allowing inter-comparability between the different expeditions. A Nansen or a Bongo net was deployed only during four cruises. Maximum sampling depth varied greatly among stations due to different bottom depths. However, during 11 cruises to the Southern Ocean the maximum sampling depth was restricted to 1000m, even at locations with greater bottom depths. In the eastern Atlantic Ocean (PS63) sampling depth was restricted to the upper 300m. All data are now freely available at PANGAEA via the persistent identifier https://doi.org/10.1594/PANGAEA.884619. Abundance and distribution data for 284 calanoid copepod species and 28 taxa of other copepod orders are provided. For selected species the abundance distribution at all stations was explored, revealing for example that species within a genus may have contrasting distribution patterns (Ctenocalanus, Stephos). In combination with the corresponding metadata (sampling data and time, latitude, longitude, bottom depth, sampling depth interval) the analysis of the data sets may add to a better understanding how the environment (currents, temperature, depths, season) interacts with copepod abundance, distribution and diversity. For each calanoid copepod species, females, males and copepodites were counted separately, providing a unique resource for biodiversity and modelling studies. For selected species the five copepodite stages were also counted separately, thus also allowing the data to be used to study life cycle strategies of abundant or key species.