RESPONSES OF LIVING (ROSE BENGAL STAINED) BENTHIC FORAMINIFERA TO CONTAMINANTS IN THE VENICE LAGOON, ITALY

The ecology of living benthic foraminifera in the Venice Lagoon was assessed as part of an ongoing international effort examining the biota and chemistry of Lagoonal sediments (SIOSED: SCRIPPS Institution of Oceanography SEDiment Research Group).  Vertical distribution patterns of living (Rose Bengal-stained) foraminiferal assemblages (>150µm) were examined in sediments from push cores taken on a transect of contaminated sediments within the Lagoon.  Calcareous taxa comprised 90% of foraminiferal assemblages at sites within class B, and C contamination zones, whereas agglutinated taxa dominated the site within the class A contamination zone.  At a site within zone B, maximum foraminiferal assemblage densities occurred at the surface (0-1cm), whereas a site within zone C (the most contaminated zone) had an infaunal density maximum.  Dominant taxa at sites within B, and C zones included: Ammonia sp., Haynesina sp., and Quinqueloculina sp.   Dominant taxa at the site within zone A (the least contaminated zone) included: Reophax sp.  Foraminifera were assessed for abnormal test morphologies that previous studies of other areas suggest may be related to the existence of contaminants in the sediments.  Differences in populations and aberrant morphologies at sites A, B, and C may be related to pollutant concentrations.   Results may provide calibration data for proxies of spatial and temporal environmental change.