Effects of pollution on marine gastrotricha in the northwestern Adriatic Sea

The barrier islands and coast south and east ofVenice,Italy, were sampled in parallel to the work of Schromtwo decades ago. Where he found 49 site records for 24species ofgastrotrichs at 8 sites,5 littoral and 3 shallowsublittoral, we found 5 site records for 2 species at 9sites, 5 littoral and 4 shallow sublittoral. We had no siterecords from littoral sites; one specieso Dolichodasyselongatrr, occurred at all sublittoral sites. Fromother locations (n:15) in our present survey of theItalian coastline, where we have paired littoral:sublittoralsites, we have found 6.7 (10.9) species in theformer and 8.0 (10.9) in the latter. The absence ofgastrotrichs in samples from all five littoral sites and thedominance of D. elongalus in sublittoral sites is clearevidence as to the severity of pollution in this area.However, five species were found in a sample from thetop of a longshore bar at one location, indicating that atype of local refugium exists from which future recolonizationof the remaining habitat could proceed, ifthe input of pollutants can tre reversed.