| Summary |
Twenty-nine epifaunal species were collected from four stations in the Pamlico River estuary. Asbestos-cement panels submerged for 1, 3, and 12 month periods from March, 1972, through February, 1973, served as attachment surfaces. Three distinct groupings of taxa, or communities were present. The dominant epifauna at the mouth of the river, the permanently mesohaline portion of the estuary were: the hydroid, Garveia cer︢l︣ea; the barnacle, Balanus improvisus; the bryozoans Victorella pavida and Membranipora tenuis; the anemone, Diadumene leucolena; and the polychetes, Polydora websteri and Nereis succinca. The epifaunal community in upriver, oligohallne portions of the estuary was dominated by: the hydroid, Cordylophora caspia; the barnacle, Balanus amphitrlte pallidus; the bryozoan, Victorella pavida, and the polychaete, Polydora websteri. The intermediate zone was occupied by forms found in previously described communities: Balanus imprcvisus; Cordylophora caspia ; Victorella pavida; Polydora websteri; and the amphipod, Corophium lacustre. Salinity was the major factor influencing distribution of organisms and demarcation of communities. Species diversity decreased at successively upriver stations. Great seasonal variation in species composition relative abundance, and dry weight production was observed in each community. Epifauna were abundant in warmer months (May through October) and sparse in cooler months (November through April). Seasonal expressions in community structure were primarily influenced by larval settlement, which in turn was controlled by temperature, dissolved oxygen, salinity and interspecific competition. Seasonal variation in epifaunal species composition masked successional patterns; generally, however, attachment of protozoa and bacteria was followed by colonization of sessile species. Soon after, motile forms became associated with existing sedentary organisms. |
