Biomass and substrate utilization of cold adapted bacteria in Fram Strait and the Western Greenlad Sea

During the 'Polarstern' expedition ARK-IV/2 in June 1987, water samples from 8 stations were taken to study biomass and substrate utilization of cold adapted bacteria. Bacterial biomasses determined from acridine orange direct counts (AODC) were between 0.4 and 31.4 µ/g C/l, and ATP concentrations amounted from <0.1 to 40 ng/l. Colony counts on seawater agar reached only 0.1% of AODC, but with the MPN-method 1 to 10% of AODC were recorded. With 14C-glutamic acid or 14C-glucose as tracer substrate in oligotrophic broth containing 0.5 mg trypticase and 0.05 mg yeast extract per liter of seawater, obligately oligotrophic bacteria could be detected in one water sample. Although incubation was at 2 °C, only psychrotrophic bacteria showing growth temperatures between 1 and 30 °C were obtained. Organic substrate utilizations by 106 isolates were tested at 4 and 20 °C. Most carbohydrates, organic acids, alcohols, and alanine were assimilated at both temperatures, but arginine, aspartate and ornithine were utilized only at 20 °C by almost all strains.

Abundance and biomass of planktonic diatom Proboscia alata and associated species, chlorophyll a, organic carbon and nitrogen concentrations in waters over the Bering Sea middle shelf in August 2001

During most of the vegetation season from late May to early September large-sized diatom alga Proboscia alata forms local patches with high abundances and biomasses in different oceanographic domains of the eastern Bering Sea shelf. For 0-25 m layer average abundance and biomass of species in these patches are 700000 cells/l and 5 g/m**3 (wet weight), while corresponding estimates for the layer of maximal species concentrations are 40000000 cells/l and 38 g/m**3 (wet weight) or 1.6 g C/m**3. These levels of abundance and biomass are typical for the spring diatom bloom in the region. Outbursts of P. alata mass development are important for the carbon cycle in the pelagic zone of the shelf area in the summer season. The paradox of P. alata summertime blooms over the middle shelf lies in their occurrences against the background of the sharp seasonal pycnocline and deficiency in nutrients in the upper mixed layer. Duration of the outbursts in P. alata development is about two weeks and size of patches with high abundances can be as large as 200 km across. Degradation of the P. alata summertime outbursts may occur during 4-5 days. Rapid sinking of cells through the seasonal pycnocline results in intense transport of organic matter to bottom sediments. One of possible factors responsible for rapid degradation of the blooms is affect on the population by ectoparasitic flagellates. At terminal stages of the P. alata blooms percentage of infected cells can reach 70-99%.

Particulate organic carbon flux of moored sediment traps

We report primary production of organic matter and organic carbon removal from three subtropical open ocean time-series stations, two located in the Atlantic and one in the Pacific, to quantify the biological components of the oceanic carbon pump. We find that within subtropical gyres, export production varies considerably despite similar phytoplankton biomass and productivity. We provide evidence that the removal of organic carbon is linked to differences in nutrient input into the mixed layer, both from eddy induced mixing and dinitrogen fixation. These findings contribute to our knowledge of the spatial heterogeneity of the subtropical oceans, which make up more than 50% of all ocean area and are thought to spread in the course of CO2- induced global warming.

(Table 2) Plankton biomass and production in the Burgas Bay, Black Sea

Distribution of mesoplankton in the Burgas Bay in 53 bottle samples taken in October-November 1982 is discussed. Decrease in total biomass of zooplankton from north to south can be traced at the northern meridional section (Cape Krotiriya to Cape Kaliakra), probably resulting from decrease in eutrophicating effect of the Danube River in this direction. Plankton off the Bulgarian coast was in typical autumn condition. In the southern part of the Burgas Bay, where there is discharge current carrying eutrophicated sewage from the city of Burgas, various stages in development of the community, from a young community in the inner end of the bay to a mature one at its outlet, were observed.

Prosome length as well as carbon and nitrogen content of Calanus finmarchicus from the North Atlantic collected during Maria S. Merian cruise MSM26 in spring 2013

The prosome length of copepods from each station was measured on board with a dissecting microscope equipped with an ocular micrometer. Individuals were placed in pre-weighed tin caps and dried for 48 h at 60°C on board. Dry samples were transferred to the AWI and weighed again. Copepod dry mass was then calculated as the difference between the empty weight and the weight of the tin cap containing one individual. The content of carbon (C) and nitrogen (N) then was analysed with a CN-analyser (EuroEA Element Analyser, Hekatech) with acetanilide as standard.