There is some indication that elevated turbidity can reduce thermal bleaching damage to reefs, suggesting a photo-protective effect during thermal anomalies Dabrafenib supplier making shallow-water corals in turbid waters less susceptible to bleaching than those in clear waters (Phongsuwan, 1998 and Piniak and Storlazzi, 2008) but this requires further study. Sedimentation and burial in the marine environment are measured and expressed in a number of different

ways. Sedimentation (sometimes also called “siltation” or “deposition”) is usually expressed as a rate (in mg cm−2 d−1) or in thickness (mm) of the sediment layer (instantaneous, or accumulating over time). Water turbidity and sedimentation correlate only in part because increased turbidity does not necessarily lead to buy Belnacasan increased sediment deposition (Larcombe and Woolfe, 1999). A range of methods is available for field measurements

of sediment accumulation or sediment elevation change in underwater environments, all of which have merits and shortcomings (Thomas and Ridd, 2004). Despite their widespread use in this setting, sediment traps do not provide quantitative information about “net” sedimentation on coral surfaces (Storlazzi et al., 2011). Sediment traps can, however, yield useful information about the relative magnitude of sediment dynamics in different areas, as long as trap deployment standards are used for trap height, trap-mouth diameter, height of trap mouth above the substrate and spacing between traps (Jordan et al., 2010 and Storlazzi et al., 2011). Sedimentation on coral reefs may cause smothering of coral polyps (Fig. 3; Fabricius and Wolanski, 2000), inhibiting photosynthetic production and increasing respiration as well as creating a diffusion barrier. In a study by Abdel-Salam and Porter (1988), daytime photosynthesis in corals exposed to

sediments decreased, while at night-time respiration increased. Stafford-Smith (1993) measured a drop in photosynthesis Chloroambucil to respiration (P:R) ratios for smothered corals. Corals will attempt to clean themselves of this sediment by a combination of ciliary action and the production and sloughing off of mucus sheets. This, however, is expensive in energy and can lead to exhaustion of mucus-producing cells (Peters and Pilson, 1985, Riegl and Bloomer, 1995 and Riegl and Branch, 1995). At the individual (colony) level, energy diverted to clearing the colony surface of sediment can lead to growth inhibition and a reduction in other metabolic processes (Dodge and Vaisnys, 1977, Rogers, 1983 and Edmunds and Davies, 1989).