Coccolithophorids in the phytoplankton of the eastern Bering Sea after the anomalous bloom of 1997

Based on the results of the field observations in August 1998, July 2000, and August 2001, the composition and quantitative distribution of coccolithophorids in the middle domain of the Eastern Bering Sea shelf between 56degrees52' and 59degrees19' N is characterized. The abundance, biomass, and size structure of the Emiliania huxleyi population as well as its role in the coccolithophorid community and in the phytocoenosis as a whole were evaluated. The abundance of this species in the upper mixed layer in the bloom areas was 1-3 x 10(6) cells/l and its biomass made up 30-7.5 mg C/m(3). The share of E. huxleyi in the total phytoplankton abundance and biomass reached 98 and 84%, respectively. The significant spatial heterogeneity of the quantitative distribution and the population size structure, as well as the asynchronism in the population development of E. huxleyi in the neighboring parts of the bloom area, are shown. The period during which the population structure in a certain part of the area develops from the domination of juvenile cells without coccoliths to the phase of active detritus formation with dying coccolithophorid cells involved may be estimated as two weeks. A conclusion is made that, after the anomalous E. huxleyi bloom in 1997, mass development of coccolithophorids became a characteristic feature of the phytoplankton community's seasonal succession in the middle domain of the eastern Bering Sea shelf.