Protistology 3 (2) 107–120 (2003) Vertical structure of the interstitial ciliate community in the Chernaya River estuary (the White Sea)
Yuri A. Mazei 1 and Igor V. Burkovsky 2
1 Department of Ecology, Penza State Pedagogical University, Penza, Russia
Summary
Vertical structure of the interstitial ciliate community in the Chernaya River estuary (the White Sea) was investigated. Distinct
change of the species structure of the ciliate community in the sediment column is observed at all stations in the estuary along the
salinity gradient. There are three species groups, which prefer certain horizons of the sediment: 1) eurytopic species, not specific for
the interstitial, occupying top horizons of the sediment; 2) basic structure-forming species represented by specific interstitial ciliates
in the marine part of the estuary. They occupy subsurface layers and develop down to the border of the H2S zone; 3)
microaerophilous and anaerobic organisms, occupying the deepest layers of the sediment. A decrease in biomass, abundance,
species richness and diversity of ciliate community with depth is detected. A sharp vertical Eh-gradient in the freshened zone of the
estuary results in concentration of different ciliate species within the limits of small layers and, as a result, in sharp vertical
differentiation of the community. Moreover, in the freshened zone most of abundance and biomass of ciliates (more than 70 %) is
concentrated in the top 0.5 cm layer of the sediment. More gradual changes of the Eh-gradient and its higher absolute value in the
marine zone determine deeper penetration of many species into the sediment and, as a consequence, a smaller differentiation of the
community.
Key words: interstitial ciliates, vertical distribution, community structure
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