Freshwater springs on intertidal sand flats cause a switch in dominance among polychaete worms
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101; e-ISSN 1873-1414, more
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| Keywords |
Environmental effects > Salinity effects
Environments > Aquatic environment > Marine environment > Intertidal environment
Interspecific relationships > Competition
Sedimentary structures > Bed forms > Sand bars
Water > Brackish water
Arenicola marina (Linnaeus, 1758) [WoRMS]; Nereis virens Sars, 1835 [WoRMS]
ANE, Germany, Schleswig-Holstein, Sylt I. [Marine Regions]
Marine/Coastal |
| Author keywords |
groundwater seepage; brackish water; intertidal sandflat; competition;Arenicola; Nereis |
| Abstract |
Effects of freshwater seepage on benthic macrofauna were investigated on the sandy tidal flats near the island of Sylt (German Wadden Sea) in 2002. Several permanent seepage areas (50 to 200 m offshore; up to 200 m2 in area) were examined, in which salinity ranged from 22-29 outside to 0-16 psu inside seepage areas in the upper 20 cm of sediment during summer low tides. The freshwater seepage areas were characterised by an absence of lugworms (Arenicola marina) and a twelve-fold increase in nereid polychaetes (Nereis diversicolor and N. virens) relative to non-seepage areas. Lugworms and ragworms were scarce in a transition zone, which was colonised by juvenile lugworms. We suggest that nereid polychaetes avoid competition with bioturbating lugworms by adapting to areas of low salinity (freshwater seepage). |
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