Abundance and biomass of in- and epibenthic invertebrate macrofauna in the German Bight from 1969 to 2000

In order to examine the long-term development of offshore macrozoobenthic soft-bottom communities of the German Bight, four representative permanent stations (MZB-SSd, -FSd, -Slt, -WB) have been sampled continuously since 1969. Inter-annual variability and possible long-term trends were analysed based on spring-time samples from 1969 until 2000. This is part of the ecological long-term series of the AWI and is supplemented by periodic large-scale mapping of the benthos. The main factors influencing the development of the benthic communities are biological interactions, climate, food supply (eutrophication) and the disturbance regime. The most frequent disturbances are sediment relocations during strong storms or by bottom trawling, while occasional oxygen deficiencies and extremely cold winters are important disturbance events working on a much larger scale. Benthic communities at the sampling stations show a large inter-annual variability combined with a variation on a roughly decadal scale. In accordance with large-scale system shifts reported for the North Sea, benthic community transitions occurred between roughly the 1970ies, 80ies and 90ies. The transitions between periods are not distinctly marked by strong changes but rather reflected in gradual changes of the species composition and dominance structure.

Abundance and biomass of gelatinous plankton in the southern part of the Black Sea in June 1991

Cruise 1991-06 conductucted covering TEEZ with a large cruise presents a dataset of macro gelatinous biomass and abundance in the Southern Black Sea in June 1991.

(Table 2) Biomass and size characteristics of Aurelia aurita in the Black Sea as determined from the Argus manned submersible

Based on estimate of Aurelia aurita concentration in the Black Sea from the Argus manned submersible in April-May 1984, as well as on author's data and published information on metabolic rate and feeding of medusa, biomass of medusa Aurelia aurita in the epipelagic zone of the Black Sea is estimated to be about 400 million tons of wet weight, and its mean annual production to be 400-900 million tons wet weight or about 1.1-2.5 million tons of organic carbon, equivalent to approximately 1-3% of primary production.

Export of algal biomass from the melting Arctic sea ice

In the Arctic, under-ice primary production is limited to summer months and is not only restricted by ice thickness and snow cover but also by the stratification of the water column, which constrains nutrient supply for algal growth. RV Polarstern visited the ice-covered Eastern Central basins between 82 to 89°N and 30 to 130°E in summer 2012 when Arctic sea ice declined to a record minimum. During this cruise, we observed a widespread deposition of ice algal biomass of on average 9 g C per m**2 to the deep-sea floor of the Central Arctic basins. Data from this cruise will contribute to assessing the impact of current climate change on Arctic productivity, biodiversity, and ecological function.