Chronic exposure of corals to fine sediments: lethal and sub-lethal impacts

Flores, Florita, Hoogenboom, Mia O., Smith, Luke D., Cooper, Timothy F., Abrego, David, and Negri, Andrew P. (2012) Chronic exposure of corals to fine sediments: lethal and sub-lethal impacts. PLoS ONE, 7 (5). pp. 1-12.

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Abstract

Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS) for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata) more than the upright branching species (Acropora millepora). The lowest sediment treatments that caused full colony mortality were 30 mg l⁻¹ TSS (25 mg cm⁻² day⁻¹) for M. aequituberculata and 100 mg l⁻¹ TSS (83 mg cm⁻² day⁻¹) for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue.

Item ID: 22979
Item Type: Article (Research - C1)
ISSN: 1932-6203
Additional Information:

© 2012 Flores et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funders: Woodside Energy
Date Deposited: 15 Aug 2012 05:32
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity @ 10%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060203 Ecological Physiology @ 50%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 40%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960808 Marine Flora, Fauna and Biodiversity @ 100%
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