Effects of thermal power station effluent on the seagrass benthic communities of Lake Macquarie, a New South Wales coastal lagoon.

Abstract

The structure of seagrass macrofauna communities in the path of the outfall of Vales Point Power Station, Lake Macquarie, NSW, was assessed between July 1977 and April 1980 and related to distance from the outfall. During the first part of the study (power station generating capacity of 875 mW) major differences were shown in the structure of the site adjacent to the outfall when compared with controls. These included fewer species (especially large filter feeding bivalves), more individuals (particularly grazing gastropods) and different seagrass types. There were also slight differences in other sited within the thermal plume. The expansion of the generating capacity of the power station to 2195 mW resulted in a greater reduction in species number and individuals and total loss of seagrass adjacent to the outfall. Other areas within the plume underwent a change in seagrass type, a reduction in species numbers (especially filter feeding bivalves) and an increase in the numbers of grazing gastropods. Control sites remained unchanged. The possible role of various factors in determining community structure is discussed.