(Table 2) Concentration of phytoplankton pigments in Adventfjorden in spring and summer of 1997

The study was carried out from April 30 until July 13 of 1997 in Adventfjorden (Spitsbergen). Formation of a less saline and warmer surface water (~1 m thick) caused by melting of the ice was observed in the fjord during the first days of May. In summer the less saline surface layer was about 3 m thick. Euphotic depth measured under the ice sheet reached 12 m, whereas load of mineral matter brought with riverine discharge in summer (content of total particulate matter in the fjord reached 1.66 kg/m**2) dramatically reduced euphotic zone depth to 0.35 m. By pigment measurement three phases of phytoplankton development in Adventfjorden were distinguished: (1) spring bloom that has started under fast ice and reached maximum in the mid of May, (2) stagnation period in June, (3) increase of pigment concentration in July, what could indicate start of the next algae bloom. Analyses of chlorophylls and carotenoids revealed that diatoms (chl c, fucoxanthin), and green algae (chl b, lutein) dominated phytoplankton community in the fjord. Moreover, presence of peridinin indicates presence of Dinophyta and alloxanthin - occurence of Cryptophyta. In May and June 1997 phytoplankton appeared mainly in the surface of water, while in July, as a result of inflow of turbulent riverine waters into Adventfjorden, algae cells were pushed down and the highest numbers were observed at depth ~20 m. Great phaeopigments to chl a ratio (= 0.54) found in fjord seston in June and July probably shows strong impact of zooplankton grazing on phytoplankton development. High contribution of chlorophyllide a in porphyrin a poll in samples collected under fast ice (chlorophyllide a / chl a ratio = 0.18) reflects the final stage of algal communitie succession in ice, just before spring ice melt and release of biota to oceanic water. Chlorophyllide a content during summer was minor or not detectable, demonstrating that diatom cells were in good physiological condition. High chl a allomer / chl a ratio (average = 0.11 for the period investigated) confirms high oxygen concentration in environment of Adventfjorden.

ATP, chlorophyll "a", and size structure of phytolpankton in seawater at stations in the Atlantic sector of the Southern Ocean

Chlorophyll "a" and adenozine triphosphate (ATP) concentrations together with size structure of microplankton were investigated in January-April 1989 in the Indian Ocean and in the Weddell Sea. ATP values varied from 11 to 92 ng/l, and chlorophyll "a" concentrations varied from 0.04 to 0.27 µg/l in the Indian Ocean, with prevailing nanoplankton and picoplankton fractions. Both ATP and chlorophyll "a" concentrations increased 2 times to the south of 40°S; in the Weddell Sea they exceeded 400 ng/l and 0.6 µg/l, respectively. Cells of nanophytoplankton and microphytoplankton (mainly diatoms) prevailed in size spectra. Spatial variabilities of the parameters were within one order of magnitude; their values decreased 3-4 times during 1 month. Size structure changed due to increased portion of nanoplankton and picolankton. ATP concentrations in the photic layer (0-200 m) varied from 31.96 mg/m**2 in February to 8.02 mg/m**2 in March to April. ATP concentrations were 61.5 and 98.8 mg/m**2 at depths of 4200 and 4700 m, respectively.

Concentration of organic compounds in slush, under-ice water, and the snow-ice fast-ice cover of the southeast sector of the Antarctic in April 2008

Data are presented on concentration of hydrocarbons (HC) relative to concentrations of suspended matter, lipids, organic carbon, and chlorophyll a in surface waters and snow-ice cover of the East Antarctic coastal areas. It was shown that growth of concentrations of aliphatic HC (AHC) to 30 µg/l in surface waters takes place in frontal zones and under young ice formation. AHC concentration in snow increases with growth of aerosol concentration in the atmosphere. In the lower part of ice, at the boundary with seawater, despite low temperatures, autochthonous processes may provide high AHC concentrations (up to 289 µg/l). Within the snow-ice cover on fast ice, concentration co-variations of all the compounds considered take place.