Impacts of turbidity on corals: The relative importance of light limitation and suspended sediments

Pia Bessell-Browne; Andrew P Negri; Rebecca Fisher; Peta L Clode; Alan Duckworth; Ross Jones

doi:10.1016/j.marpolbul.2017.01.050

Impacts of turbidity on corals: The relative importance of light limitation and suspended sediments

Mar Pollut Bull. 2017 Apr 15;117(1-2):161-170. doi: 10.1016/j.marpolbul.2017.01.050. Epub 2017 Feb 2.

Authors

Pia Bessell-Browne¹, Andrew P Negri², Rebecca Fisher³, Peta L Clode⁴, Alan Duckworth², Ross Jones⁵

Affiliations

¹ Australian Institute of Marine Science, Townsville, QLD, Australia; Australian Institute of Marine Science, Perth, WA, Australia; The Oceans Institute, The University of Western Australia, Perth, Western Australia, Australia; The Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia; Western Australian Marine Science Institution (WAMSI), Perth, Western Australia, Australia. Electronic address: pia.bessell-browne@research.uwa.edu.au.
² Australian Institute of Marine Science, Townsville, QLD, Australia; Western Australian Marine Science Institution (WAMSI), Perth, Western Australia, Australia.
³ Australian Institute of Marine Science, Perth, WA, Australia; Western Australian Marine Science Institution (WAMSI), Perth, Western Australia, Australia.
⁴ The Oceans Institute, The University of Western Australia, Perth, Western Australia, Australia; The Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia.
⁵ Australian Institute of Marine Science, Perth, WA, Australia; The Oceans Institute, The University of Western Australia, Perth, Western Australia, Australia; Western Australian Marine Science Institution (WAMSI), Perth, Western Australia, Australia.

PMID: 28162249
DOI: 10.1016/j.marpolbul.2017.01.050

Abstract

As part of an investigation of the effects of water quality from dredging/natural resuspension on reefs, the effects of suspended sediment concentrations (SSCs) (0, 30, 100mgL^-1) and light (~0, 1.1, 8.6molphotonsm^-2d^-1) were examined alone and in combination, on the corals Acropora millepora, Montipora capricornis and Porites spp. over an extended (28d) period. No effects were observed at any sediment concentrations when applied alone. All corals in the lowest light treatments lost chlorophyll a and discoloured (bleached) after a week. Coral mortality only occurred in the two lowest light treatments and was higher when simultaneously exposed to elevated SSCs. Compared to water quality data collected during large dredging programs and natural resuspension events (and in the absence of sediment deposition as a cause-effect pathway) these data suggest the light reduction associated with turbidity poses a proportionally greater risk than effects of elevated SSCs alone.

Keywords: Coral; Dredging; Light attenuation; Suspended sediment concentrations.

MeSH terms

Animals
Anthozoa*
Coral Reefs*
Geologic Sediments*
Light
Nephelometry and Turbidimetry
Water Pollutants
Water Quality*

Substances

Water Pollutants