ENVIRONMENTAL DEGRADATION IN HALIFAX HARBOUR: AN HISTORICAL PERSPECTIVE USING BENTHIC FORAMINIFERA

Abstract

Foraminiferal assemblages foro sediment surface samples collected in Bedford Basin, ·Halifax Harbour, in August 1992, have been investigated and compared to foraminiferal data from 1970 to determine faunal changes resulting from environmental degradation within the highly polluted estuarine system. The assemblages were related to contaminants such as organic matter and increased metal concentration (that are among the highest in economically developed countries around the world). Using foraminiferal data from two cores collected in 1996, faunal changes were determined between the subrecent and modem fauna. Foraminiferal abundance and diversity was mostly lower in the present assemblages compared to 1970, and an evident decrease in calcareous species diversity was noted that is probably caused by an increased organic matter influx from anthropogenic sources. In sediments with enhanced metal concentration, the foraminiferal abundance was decreased. The cores, comprising about a century in time, show almost an absence of calcareous fauna. The abundance was lowest in the top em. The species Eggerella ad\·ena, known for an affinity to organic pollution, increased in both cores towards the top.

Keywords: benthic foraminifera, Halifax Harbour, estuarine. organic matter, ·pollution, heavy metal pollution, historical perspective, Canada. Pages: 84 Supervisor: David Scott