Project Report PR-94-15
Benthic Faunal Sampling Adjacent to Barbers Point Ocean Outfall, Oahu, Hawaii, June 1993
Walter G. Nelson, Julie H. Bailey – Brock, William J. Cooke, and E. Alison Kay
Benthic infauna in the vicinity of the Barbers Point Ocean Outfall was sampled at seven stations along the diffuser isobath in June 1993. Stations were located both within and on the boundary of the zone of initial dilution (ZID) and at distances of 0.5 and 3.5 km from the ZID boundary. Sediment grain-size distributions of mainly fine to coarse sands were generally similar at most stations, although Station HB6 had relatively coarser sediments than the other stations. There was a greater percentage of fine sediments at all stations in 1993 relative to previous years, perhaps due to the effects of Hurricane Iniki. Values for total organic carbon in the sediments were higher at all stations in 1993 than in previous years. The increase is believed to be due to changes in analytical techniques. Values for total organics were not elevated at stations in or near the ZID. Values of oxidation-reduction potential showed no indication of significant organic buildup in sediments at any station. From comparisons of abundance and species richness among stations, no pattern of significant differences that could be related to proximity to the diffuser pipe was determined for any faunal component. Species diversity and evenness for both nonmollusks and mollusks were similar at most stations. Cluster analysis indicated that all stations were relatively similar in nonmollusk community composition.