Ref ID : 1735
P. Jensen; Ecology of benthic and epiphytic nematodes in brackish waters. Hydrobiologia 108:201-217, 1984
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Abundances of benthic nematodes from shallow waters in Tvarminne, Finland and in Ringkobing Fjord, Denmark averaged 1.2-1.5x10E6 individuals m-2. Less than 20 species were found. More than 80% of the individuals were made up by Anoplostoma viviparum, Chromadorita fennica, Axonolaimus spinosus, Daptonema trabeculosum and Sabatieria pulchra. S. pulchra is designated as an anoxybiotic species and is attracted to the root tips of young Potamogeton perfoliatus, whilst A. viviparum and C. fennica are oxybiotic species. Abundance of epiphytic nematodes extracted from submerged macrophytes in the Cladophora-Pilayella belt in the outer archipelago of the Finnish archipelago (July 1978) was estimated to reach 5x10E6 individuals m-2, equivalent to a biomass of 1.2 g-org.C m-2. Abundance and biomass are smaller in the Potamogeton meadows in the inner archipelago, in littoral algal vegetation of the sea zone, and on sublittoral vegetation. Epiphytic nematode species composition is influenced by salinity and food availability and not by physiognomic types or silt contents of the vegetation in the Baltic Sea, European estuaries and lakes. Dominant species are: Chromadorina bioculata, Punctodora ratzeburgensis, Chromadorita tenuis, Adoncholaimus thalassophygas, Theristus acer, Monhystera parva, M. aff. filiformis and Chromadora aff. nudicapitata. A theory is proposed to explain observed seasonal changes in the species composition of epiphytic and benthic nematodes. During winter months, the submerged vegetation is mostly destroyed, being found as detritus on the sea bottom. Sampling benthic nematodes during winter thus includes epiphytic species living in the detritus. In spring the epiphytic nematodes detect the newly growing vegetation, leave the sea bottom, colonize the submerged vegetation and spend their life there.