Effects of land-based pollution on Indonesian coral reefs: biodiversity, growth rates, bioerosion, and applications to the fossil record

Abstract

<p>Land-based pollution has dramatic effects on coral species diversity, live coral cover, morphological composition of the coral fauna, coral growth rates, coral bioerosion intensity, and reef carbonate budgets. Pollution damage is measured in surveys of eight Java Sea reefs and eight reefs in Ambon and Sulawesi, Indonesia. Reefs subject to land-based pollution show are 30-50% less diverse at 3m, nad 40-60% less diverse at 10m depth, than unpolluted reefs in the same region. Polluted reefs are dominated by massive and submassive corals, and have almost no Acropora corals. Unpolluted reefs are dominated by Acropora at 3m, and by branching or foliose corals at 10m. Morphological composition ternary diagrams estimate reef conservation value. Eutrophication has a two-faced effect on corals and coral reefs called the Janus Effect. Coral growth rates on polluted reefs are as high or higher than on unpolluted reefs. Coral growth rates in Java are positively correlated with eutrophication and sedimentation. Live coral cover and coral skeletal density are lower on polluted reefs than on unpolluted reefs, and bioerosion in highest on polluted reefs. The most eutrophic Java Sea reef has a negative carbonate budget, while an unpolluted fringing reef and coral cay both have positive carbonate budgets. Bioeroding organism frequency in branching coral rubble follows trends in massive coral bioerosion on Java Sea reefs, and can be used as non-destructive indicator of eutrophication on reefs. individual sponge boring size accurately reflects total bioerosion in modern corals on the Great Barrier Reef. Sponge borehole size varies with both facies and nutrient level in Puerto Rican fossil reefs, and can be used to estimate paleoproductivity. Geography and oceanography of the Java Sea are similar to the reef-bearing Middle Devonian Onondaga Formation. Java Sea reefs can be used to develop facies models for eperic sea fossil reefs.</p>