MEPS 166:119-130 (1998)  -  doi:10.3354/meps166119

Bioerosion of experimental substrates on high islands and on atoll lagoons (French Polynesia) after two years of exposure

N. Pari1,2,*, M. Peyrot-Clausade1, T. Le Campion-Alsumard1, P. Hutchings3, V. Chazottes2, S. Golubic4, J. Le Campion1, M. F. Fontaine1

1Centre d'Océanologie de Marseille, UMR CNRS 6540, Université de la Méditerranée, Station Marine d'Endoume, rue de la Batterie des Lions, F-13007 Marseille, France 2Centre de Sédimentologie et Paléontologie, UPRESA CNRS 6019, Université de Provence, Aix-Marseille I, case 67, F-13331 Marseille cedex 03, France 3The Australian Museum, 6-8 College Street, 2000 Sydney, New South Wales, Australia 4Department of Biology, Boston University, Boston, Massachusetts 02215, USA

Rates of bioerosion by grazing and boring were studied in lagoons of 2 high islands (3 sites) and 2 atolls (2 sites each) in French Polynesia using experimental carbonate substrates (blocks of Porites lutea skeleton). The substrate loss versus accretion was measured after 6 and 24 mo of exposure. The results show significant differences between pristine environments on atolls and environments on high islands subjected to different levels of eutrophication and pollution due to human activities. Whereas experimental substrates on the atolls maintain a balance between accretion and erosion or exhibit net gains from accretion (positive budget), only 1 site on a high island exhibits significant loss of substrate by net erosion (negative budget). The erosional patterns set within the first 6 mo of exposure were largely maintained throughout the entire duration of the experiment. The intensity of bioerosion by grazing increases dramatically when reefs are exposed to pollution from harbour waters; this is shown at one of the Tahiti sites, where the highest average bioerosional loss, up to 25 kg m-2 yr-1 (6.9 kg m-2 yr-1 on a single isolated block), of carbonate substrate was recorded.

Bioerosion · Experimental substrates · Coral reefs · French Polynesia

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