Zooplankton collected in the ice covered Chupa Inlet (White Sea) on 6-7 April 2002

Size-, species- and age composition of zooplankton was studied in the ice-covered Chupa Inlet (White Sea, Kandalksha Bay) in early April 2002. The species composition of zooplankton was poor and typical for the end of the winter season, and abundance and biomass were considerably lower than in summer. In terms of biomass two species of copepods (Calanus glacialis and Pseudocalanus minutus) prevailed. Both species were already feeding on ice algae available and began to reproduce. Such early reproduction of Calanus glacialis was noted in the White Sea for the first time. Obtained results show that secondary production in the White Sea starts well before thawing of the ice cover.

Mesozooplankton of the northern Barents Sea in October 1998

Qualitative and quantitative mesozooplankton composition was examined on materials collected during an expedition carried out in October 1998 onboard the research icebreaker Akademik Fedorov. At different stations number of species varied from 25 to 33; wet biomass - from 20 to 109 g/m**2. Flux of autochthonous organic matter through plankton communities calculated from data on structural and functional analysis was from 2 to 40 mg C/m**2/day.

Study on the effects of near-future ocean acidification on marine yeasts: a microcosm approach

Marine yeasts play an important role in biodegradation and nutrient cycling and are often associated with marine flora and fauna. They show maximum growth at pH levels lower than present-day seawater pH. Thus, contrary to many other marine organisms, they may actually profit from ocean acidification. Hence, we conducted a microcosm study, incubating natural seawater from the North Sea at present-day pH (8.10) and two near-future pH levels (7.81 and 7.67). Yeasts were isolated from the initial seawater sample and after 2 and 4 weeks of incubation. Isolates were classified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and representative isolates were identified by partial sequencing of the large subunit rRNA gene. From the initial seawater sample, we predominantly isolated a yeast-like filamentous fungus related to Aureobasidium pullulans, Cryptococcus sp., Candida sake, and various cold-adapted yeasts. After incubation, we found more different yeast species at near-future pH levels than at present-day pH. Yeasts reacting to low pH were related to Leucosporidium scottii, Rhodotorula mucilaginosa, Cryptococcus sp., and Debaryomyces hansenii. Our results suggest that these yeasts will benefit from seawater pH reductions and give a first indication that the importance of yeasts will increase in a more acidic ocean.