Abstract
Survival and settlement of Pocillopora damicornis larvae on hard surfaces covered with fine (<63 µm) terrigenous red clay was measured in laboratory Petri dishes. The dishes were prepared with sediment films of various thicknesses covering the bottoms. Coral larvae were incubated in the dishes for two weeks and the percent that settled on the bottom was determined. There was a statistically significant relationship between the amount of sediment and coral recruitment on the bottom, with no recruitment on surfaces having a sediment cover above 0.9 mg cm−2. Experimental conditions for the delicate coral larvae were favorable in these experiments. Total survival over the two week settlement tests expressed as the sum of coral recruits and live larvae at the end of the experiment did not show a significant decline, so the major impact of the sediment was on successful settlement rather than on mortality. Larval substrate selection behavior was the primary factor in the observed result.
Highlights
Sedimentation has been identified as a major detrimental factor on coral reefs (Johannes, 1975; Cortes & Risk, 1985; Rogers, 1990; Grigg & Birkeland, 1997). Fabricius (2005) noted that evaluation of the impact of terrestrial runoff on coral reef ecology is very difficult even though sedimentation has a very high impact relative to other processes
An inverse relationship has been established between sediment loading and coral larval survival and development (Gilmour, 1999)
Experiments were conducted in Petri dishes in the laboratory at the Hawai‘i Institute of Marine Biology located on Moku o Lo‘e Island in Kane‘ohe Bay, O‘ahu. Settlement of planulae larvae of the reef coral Pocillopora damicornis on hard surfaces covered with various amounts of fine sediment was measured
Summary
Sedimentation has been identified as a major detrimental factor on coral reefs (Johannes, 1975; Cortes & Risk, 1985; Rogers, 1990; Grigg & Birkeland, 1997). Fabricius (2005) noted that evaluation of the impact of terrestrial runoff on coral reef ecology is very difficult even though sedimentation has a very high impact relative to other processes. Sedimentation has been identified as a major detrimental factor on coral reefs (Johannes, 1975; Cortes & Risk, 1985; Rogers, 1990; Grigg & Birkeland, 1997). Fabricius (2005) noted that evaluation of the impact of terrestrial runoff on coral reef ecology is very difficult even though sedimentation has a very high impact relative to other processes. Research has identified lethal and sub-lethal effects to corals from substances associated with sediments such as pesticides, fertilizers, and petroleum products (Glynn et al, 1989; Te, 2001). Particles can act as substrate for these chemicals and other contaminants These pollutants carried in sediments can affect settlement, recruitment, and survivorship of coral and their larvae. Even low levels of these toxins have been shown to dramatically affect morphology and physiological processes of corals (Glynn et al, 1986)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
