| Author Title Journal |
Düren R, Ax P (1993) Thalassogene Plathelminthen aus Sandstraenden von Elbe und Weser. Microfauna Marina 8: 267-280 |
Abstract / Notes
"Three medium-sand beaches of the rivers Weser and Elbe were studied with respect to colonization by Plathelminthes of marine origin (June 1990 - May 1991): (1) In the natural brackish-water of the Weser-estuary south of Bremerhaven (salinity 7-11 ppt), (2) in the industrially saline area of the Weser south of Bremen (4-8 ppt) and (3) in the freshwater area of the Elbe near Hamburg-Harburg (< 0.5 ppt).
15 thalassic plathelminth species were determined. 13 species colonize in naturally saline brackish-water area of the Weser, six species were detected in freshwater of the river Elbe.
An ecological marking will be carried out for 14 species. Four species are marine-euryhaline organisms, 10 species are specific brackish-water species.
The four euryhaline species Mecynostomum auritum, Placorhynchus octaculeatus, Placorhynchus dimorphis and Thylacorhynchus filostylis as also four brackish-water species (Thalassoplanella collaris, Diascorhynchus lappvikensis, Halplovejdovskya subterranea, Baicalellia subsalina) were detected only in the brackish-water of the Weser. These species of marine origin obviously can not overcome the frontier brackish-water- freshwater.
Six brackish-water species immigrate into freshwater and colonize the Elbe beach near Hamburg-Harburg, partial in high abundance. Macrostomum curvituba (30 ind. per 10 cm squared), Coelogynopora schulzii, Paramonotus hamatus, Pseudosyrtis subterranea and especially Coronhelmis multispinosus (167 ind. per 10 cm squared) and Vejdovskya ignava (150 ind. per 10 cm squared) determine the composition of the plathelminth fauna in this freshwater habitat of the Elbe."
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