Roncolato, Francesca, Fellowes, Thomas E., Duce, Stephanie, Mora, Carolina, Johansson, Oskar, Strachan, Indiana, Bugnot, Ana B., Erickson, Katherine, Figueira, Will, Gribben, Paul E., Pine, Christopher, Morgan, Bree, and Vila-Concejo, Ana (2024) Ecomorphodynamics of oyster reefs and their influence on oyster reef morphology. Geomorphology, 456. 109213.

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Abstract

Over 85 % of oyster reefs have been lost globally due to disease, overharvesting, global warming, and pollution. Consideration of the ecosystem services provided by healthy oyster reefs (e.g., coastal protection, water purification and carbon burial) has driven recent research and restoration efforts worldwide. However, hydrodynamic studies, specifically looking at the effects of different levels of wave exposure on the ecomorphodynamics of oyster reefs, are scarce. In this study, we consider oyster reefs in microtidal estuaries under different levels of relative wave exposure to determine how hydrodynamics may shape reef morphology and how reef morphology affects wave dissipation. We quantify oyster reef morphology through spatial analysis, using morphometrics and spatial density and relate these to the ability of oyster reefs to dissipate wave energy. Field campaigns were undertaken at three microtidal sites in southeast Australia with different hydrodynamic exposure and morphology: Gamay (Botany Bay), Port Hacking and Crookhaven River. We found that reef morphology and orientation is related to estuarine hydrodynamic conditions and thus we propose an ecomorphodynamic model with a continuum of morphologies from sparse reefs aligned perpendicular to the tidal currents and incoming waves (patch reefs), through broken up barriers semi-aligned or obliquely to the tidal flows (string reefs), to the total barrier that exists under the lowest hydrodynamic conditions (fringing reefs). The highest dissipative ability of locally generated wind waves occurred at Crookhaven (patch reef, 165 kW/m2), and lowest at Gamay (string reef, 11.66 kW/m2). Our results suggest that reef morphology, and orientation to currents and waves, influence wave dissipation, and that hydrodynamic conditions in turn influence reef morphology. These findings are important to inform future reef restoration under increasingly severe climate change conditions to optimise ecosystem services on restored oyster reefs.

Item ID:	85688
Item Type:	Article (Research - C1)
ISSN:	1872-695X
Keywords:	Wave dissipation; Wave exposure; Oyster reef morphology; Estuary; Gamay; Botany Bay; Port Hacking; Crookhaven
Copyright Information:	© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Date Deposited:	03 Jun 2025 00:37
FoR Codes:	37 EARTH SCIENCES > 3709 Physical geography and environmental geoscience > 370901 Geomorphology and earth surface processes @ 100%
SEO Codes:	18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180506 Oceanic processes (excl. in the Antarctic and Southern Ocean) @ 100%
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