title: Coral Ba/Ca records of sediment input to the fringing reef of the southshore of Moloka'i, Hawai'i over the last several decades.
abstract: The fringing reef of southern Moloka'i is perceived to be in decline because of land-based pollution. In the absence of historical records of sediment pollution, ratios of coral Ba/Ca were used to test the hypothesis that sedimentation has increased over time. Baseline Ba/Ca ratios co-vary with the abundance of red, terrigenous sediment visible in recent imagery. The highest values at One Ali'i are near one of the muddiest parts of the reef. This co-varies with the lowest growth rate of all the sites, perhaps because the upstream Kawela watershed was historically leveed all the way to the nearshore, providing a fast-path for sediment delivery. Sites adjacent to small, steep watersheds have ∼decadal periodicities whereas sites adjacent to mangrove forests have shorter-period fluctuations that correspond to the periodicity of sediment transport in the nearshore, rather than the watershed. All four sites show a statistically significant upward trend in Ba/Ca.
authors.affiliation: Pacific Science Center, U.S. Geological Survey, Santa Cruz, 400 Natural Bridges Drive, CA 95060, USA. nprouty@usgs.gov
authors.forename: Nancy G
authors.initials: NG
authors.lastname: Prouty
authors.forename: Michael E
authors.initials: ME
authors.lastname: Field
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Stock
authors.forename: Stacy D
authors.initials: SD
authors.lastname: Jupiter
authors.forename: Malcolm
authors.initials: M
authors.lastname: McCulloch
mesh_terms: D001464:Barium / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D057894:Coral Reefs; D019015:Geologic Sediments / Q000737:chemistry*; D006254:Hawaii; D010140:Pacific Ocean; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; D001464:Barium; D002118:Calcium