Thomson, Damian P., Dee, Shannon, Doropoulos, Christopher, Orr, Melanie, Wilson, Shaun K., and Hoey, Andrew S. (2024) High rates of erosion on a wave‐exposed fringing coral reef. Limnology and Oceanography, 69 (6). pp. 1439-1449.

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Abstract

Erosion is a key process in shaping the physical structure of coral reefs, yet due to erosion being semi-cryptic and difficult to quantify, information remains limited. Here, we investigate erosional processes along Ningaloo Reef, an extensive fringing coral reef in Western Australia. We employed both direct and indirect methods to measure erosion in wave-exposed reef slopes and protected lagoonal habitats. Direct measurements of erosion on coral blocks were among the highest found globally, with total erosion of 3.07 kg m−2 yr−1 (4% from micro, 0.6% from macro, and 94% from external), whilst indirect rates were estimated at 2.4 ± 0.20 kg m−2 yr−1 (78% from parrotfish, 22% from urchins). Indirect erosion rates were influenced by the species and size of parrotfish, with Chlorurus microrhinos removing 0.44 ± 0.19 kg m−2 yr−1 (22% of parrotfish erosion). Scanning electron microscopy and computed tomography show that micro and macroborer erosion contributions to direct erosion were low, most likely due to heavy grazing by parrotfish and the short deployment period of experimental substrates. A substantial portion of external erosion on blocks (0.53 ± 0.23 kg m−2 yr−1) could not be attributed to bioeroders and was poorly correlated with wave exposure, suggesting processes not quantified contribute to this unaccounted aspect of erosion. Our results confirm that bioerosion by parrotfish is especially significant at Ningaloo Reef, and large-bodied individuals of C. microrhinos are key in conserving this key ecological process.

Item ID:	85780
Item Type:	Article (Research - C1)
ISSN:	1939-5590
Copyright Information:	© 2024 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Date Deposited:	10 Jun 2025 22:49
FoR Codes:	31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 100%
SEO Codes:	18 ENVIRONMENTAL MANAGEMENT > 1802 Coastal and estuarine systems and management > 180202 Coastal erosion @ 100%
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