WRRCTR No.158 Micromolluscan Assemblages in Māmala Bay, O'ahu, 1974-1982

dc.contributor.author Kay, E. Alison en_US
dc.contributor.author Kawamoto, Regina en_US
dc.date.accessioned 2008-07-17T22:51:50Z
dc.date.available 2008-07-17T22:51:50Z
dc.date.issued 1983-12 en_US
dc.description.abstract The benthic communities in Mamala Bay, Oahu have been monitored since 1974 to assess the extent to which the introduction of sewage effluent at about a 70-m depth has affected the system. The index organisms utilized are micromollusks, mollusks less than about 7 mm in greatest dimension. Replicate sediment samples were obtained by modified Petersen dredge from 11 stations at 15- to 120-m depths between 1974 and 1981; samples from the diffuser and the ZID boundary were obtained by submersible-operated grab in 1982. Aliquots of sediment were sorted for micromollusks and analyzed by Q-mode cluster analysis, relative species composition, relative abundance, species diversity, and dominance. Three micromolluscan assemblages were distinguished. A Tricolia-rissoid dominated assemblage is an algal and rubble-associated assemblage of micro herbivores derivative of the reef. An infaunal assemblage with about 30% of the mollusks' carnivorous, parasitic and/or deposit feeders is associated with the occurrence of beds of the bivalve Pinna. The habits of the mollusks of the third assemblage, the dialid assemblage, are not known. Mean micromolluscan abundance tends to increase with depth; number of species and species diversity decreases with depth. Abundance is not significantly different between pre- and post-discharge stations. The Tricolia assemblage was the most frequently occurring assemblage under pre-discharge conditions; the infaunal assemblage the most frequently occurring assemblage under post-discharge conditions. In the submersible-obtained samples, only the dialid assemblage was represented at the ports of the diffuser and only the Tricolia assemblage at the ZID boundary. It is suggested that the micromolluscan assemblages in Mamala' Bay are distributed in a continuum throughout the bay, their boundaries associated with different types of sediment. No major changes in the benthos associated with the introduction of sewage effluent were detected in this study, but variations in pattern of assemblage occurrence may be the result of changes in sediments associated with diffuser activity. en_US
dc.description.sponsorship City and County of Honolulu Department of Public Works Grant/Contract No. F-322B-74 en_US
dc.format.extent viii + 73 pages en_US
dc.identifier.citation Kay EA, Kawamoto R. 1983. Micromolluscan assemblages in Māmala Bay, O'ahu, 1974-1982. Honolulu (HI): Water Resources Research Center, University of Hawaii at Manoa. WRRC technical report, 158. en_US
dc.identifier.uri http://hdl.handle.net/10125/2004
dc.language.iso en-US en_US
dc.publisher Water Resources Research Center, University of Hawaii at Manoa en_US
dc.relation.ispartofseries WRRC Technical Report en_US
dc.relation.ispartofseries 158 en_US
dc.subject micromullusks en_US
dc.subject benthic fauna en_US
dc.subject wastewater outfall en_US
dc.subject pollution effects en_US
dc.subject micromollusks en_US
dc.subject microherbivores en_US
dc.subject cluster analysis en_US
dc.subject dendograms en_US
dc.subject Sand Island Sewage Outfall en_US
dc.subject Mamala Bay en_US
dc.subject Oahu en_US
dc.subject Hawaii en_US
dc.subject.lcsh Benthos -- Hawaii -- Oahu. en_US
dc.subject.lcsh Mamala Bay (Hawaii) en_US
dc.subject.lcsh Marine pollution -- Environmental aspects -- Hawaii -- Oahu. en_US
dc.subject.lcsh Mollusks -- Effect of water pollution on. en_US
dc.subject.lcsh Sewage disposal in the ocean -- Hawaii -- Oahu. en_US
dc.title WRRCTR No.158 Micromolluscan Assemblages in Māmala Bay, O'ahu, 1974-1982 en_US
dc.type Report en_US
dc.type.dcmi Text en_US
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