Water Resources Research Act Program

Details for Project ID 2014HI432B

Temporal and spatial effects of sewage outfalls on the ecosystem health of coastal waters offshore of Honolulu

Institute: Hawaii
Year Established: 2014 Start Date: 2014-03-01 End Date: 2016-02-28
Total Federal Funds: $3,021 Total Non-Federal Funds: $7,071

Principal Investigators: Julie Bailey-Brock

Abstract: Polychaete worms are largely used as biological indicators because of their frequent high abundance and diversity on soft bottoms. Besides using the number of species and individuals to assess the community structure, species are also often classified according to their diverse feeding guilds to represent a measure of ecosystem function. Energy resources gained by these different feeding methods go into reproduction and may guarantee the survival and structure of populations. Despite the value of reproduction in maintaining the equilibrium of populations, it has never been investigated as a biological measure of ecosystem health. Syllid polychaetes have been selected as they are usually found in high abundances near the Sand Island and Barbers Point outfall’s diffusers and at reference stations. The reproductive events for these polychaetes are noted for all mature specimens in all ocean outfall biomonitoring project reports, but these data have never been used as a biological variable to investigate the effects of the outfalls on the reproductive success of polychaetes. Some syllid polychaetes in Hawaii reproduce year round and the species of interest are external brooders, therefore making it possible to observe different levels of offspring maturity. The worms have been accounted for by the presence of eggs inside the body, the number of early developing embryos attached dorsally or ventrally to the body, and the number of late developing embryos (juveniles) attached to the body. The intent of this proposal is to investigate the spatial (near the outfalls diffusers or far field at reference stations) and temporal (along 10 years of data collection) effects of the outfalls on the reproductive capabilities of syllid polychaetes by using the data recorded in the WRRC’s Project Reports. Five syllid species will be selected for this study based on their frequency and abundance in the Sand Island and Barbers Point outfall stations. The sampling stations will be categorized based on the proximity of the outfall diffusers. Ten years of data of the five species will be retrieved and tabulated according to the presence of eggs, presence and number of embryos and presence and number of juveniles. Specimens will be retrieved from the stored collection to check and confirm the reproductive stages. Multivariate analyses of variance will be performed to verify if there are significant differences on the three reproductive variables with space and time. This project will help us assess the ecosystem health around the sewage outfalls.