Influence of river discharge and wind field on the freshwater meiofauna of a dynamic river mouth area

摘要

The littoral meiofauna adjacent to a river mouth on Lake Constance (Germany) was studied in order to determine the effect of the river on the community. From February 1999 until January 2000 sets of four replicate sediment cores were collected from a total of six sampling sites on a seasonal scale. Nematodes dominated the meiofaunal community at all sites. The combined effect of wind speed and river discharge correlated strongly with the meiofaunal abundance at the four sites closest to the river mouth. In contrast, meiofauna of sites further from the river mouth were dominated by temperature, lake level variation, and nutrient-related factors. Of the meiofauna taxa observed, the presence of nematodes and oligochaetes was closely related to the interaction between wind and river. Nematodes and oligochaetes within the river-influenced littoral area seemed to be adapted to frequent changes in their habitats. However, the study also showed the complexity of littoral areas in proximity to rivers, owing to the strong interaction between the river and wind on a seasonal scale.