Publication Abstract

The impact of seabed disturbance on nematode communities: linking field and laboratory observations

M. Schratzberger*, N. Lampadariou, P.J. Somerfield, L. Vandepitte, E. Vanden Berghe

Physical disturbance is a key factor in controlling the spatial and temporal composition of shallow-water benthic communities. Like shallow waters, deeper waters are increasingly subject to a range of anthropogenic disturbances which can lead to significant alterations in sedimentation patterns. These alterations often exceed naturally occurring changes. We used a combined analysis of six independent data sets arising from large-scale field surveys and small-scale laboratory experiments to investigate the effects of seabed disturbance on nematode communities. Disturbance response was documented as a function of disturbance type (coastal development, dredged material disposal, bottom trawling, glacial fjord), origin (man-made, natural) and intensity (low, medium, high). Natural and human-induced seabed disturbance exerted differential effects on exposed populations, generating changes in the taxonomic (genus) and functional (feeding type) attributes of their assemblages. The magnitude and direction of effects was variable and depended on the origin and nature of the stress-generating factors. The genus composition of nematode assemblages from geographically separate seas converged with increased level of various types of man-made disturbance. Assemblages present along a gradient of natural disturbance at a glacial fjord followed an opposite response vector, suggesting that community changes induced by anthropogenic activities, or experimental treatments simulating the principal impacts of these, inherently differ from disturbance of natural origin. Changes in trophic diversity and structure were primarily driven by factors confounding physical disturbance such as metal contamination. Coupling the results of analyses at multiple scales proved a useful means of providing deeper insights into the general response of ecological communities to environmental change.

Reference

M. Schratzberger*, N. Lampadariou, P.J. Somerfield, L. Vandepitte, E. Vanden Berghe (2009) The impact of seabed disturbance on nematode communities: linking field and laboratory observations. Marine Biology 156: 709-724