The distribution of ice organisms was investigated in Fram Strait in May 1988 during the ARK V/1 expedition onRV Polarstern.Over a 3 week period the abundances of bacteria, diatoms, auto- and heterotrophic flagellates as well as various groups of meiofauna organisms were observed in the lowermost 30 cm of an ice floe. Data were obtained from three experimental fields under three different light regimes as a result of manipulations of the snow cover. The application of multivariate factor analysis on this time series data set resulted in the characterization of four succession stages of an Arctic sea ice community: 1) the diatom bottom assemblage, 2) the mixed autotrophic assemblage, 3) the mixed auto- and heterotrophic supra-bottom assemblage, and 4) the heterotrophic supra-bottom assemblage. The two most abundant meiofauna groups (Turbellaria, Ciliata) showed different preferences according to algal distribution. While turbellarians were most abundant in samples with mixed populations of diatoms and flagellates, ciliates reached their abundance maxima in samples dominated by diatoms, suggesting different prey selections. We have developed a model for the explanation of the spatial separation of auto- and heterotrophic organisms, highlighting the possible role of DOC production by ice algae and DOC transport with brine flow.
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