Abstract
The freshwater tidal mud-flat environments of the Elbe estuary are unique and fugitive systems with highly specific conditions. Fine grained sediments harbour a specialised and opportunistic benthic community, largely dominated by tubificid Oligochaeta and the benthic Cladocera Leydigia acanthocercoides and Iliocryptus sordidus (Crustacea, Phyllopoda) among macrofauna, together with Chironomidae. Turbellaria, Nematoda, Rotatoria, Gastrotricha and Tardigrada predominate the meiofauna. This study presents results of a small-scale sampling design, investigating distribution patterns of fauna in an area of 625 cm 2 (25×25 cm). Patchy patterns of faunal distribution of Oligochaeta, Chironomidae, Cladocera, Turbellaria and meiofauna taxa (Nematoda, Tardigrada, Gastrotricha, Rotatoria) indicate intrinsic control of abundance on small scales of less than 10 cm within the sample area (e.g. prey — predator relationships). Benthic colonisation of sediments is concentrated in the uppermost 1cm sediment layer. Parallel analysis of chloroplastic pigment contents (chlorophyll- a and c̄hloroplastic p̄igment ēquivalents — CPE) revealed regular distribution of chlorophyll- a content values in the uppermost sediment centimetre layer, reflecting recent sedimentation of abundant Actinocyclus normanii (Diatomeae) from the estuarine plankton. In deeper sediment layers distribution of chloroplastic pigment contents was patchy, and showed an overall maximum in the 2 nd centimetre layer.
Published Version
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