Distribution of benthos in a stagnant estuarine bay

Abstract

In the summers of 1974 and 1975, profiles of temperature, salinity, and dissolved oxygen were made monthly at four stations in Kennebecasis Bay. Samples of the benthic fauna and substrate were also taken.Sediment particle size distribution did not vary between stations. Combustible organic content of sediments was highest at the head of the bay and lowest near the mouth.Surface water was generally of low salinity, high dissolved oxygen, and seasonally variable temperature. Bottom water showed a stable salinity of 18 to 20‰, stable temperature of 4 to 7 °C, and stable oxygen concentrations of 1.5 to 4.5 mg/ℓ.While the parameters just mentioned are thought to be uniform throughout Kennebecasis Bay, the observed distribution pattern of species and individuals in the benthic fauna was not uniform. Samples taken at the mouth of the bay produced greater numbers of taxa and abundance of fauna than samples from the head of the bay. It is proposed that this bay mouth-to-head gradient is related to infrequent saline water inflows reaching only lower parts of Kennebecasis Bay.