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Quantifying damage to coral colonies by waterborne debris during hydrodynamic disturbances

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posted on 28.03.2022, 02:20 by Peter A. David
Physical bombardment by waterborne debris is a common disturbance in shallow coral reef systems. During hydrodynamic disturbances, such as tropical storms, increases in water velocity elevate drag forces acting on objects—ranging in size from sand to boulders and coral colonies—dislodging and propelling them into nearby coral colonies. Impact by debris can cause a number of injuries, ranging from intra-colony damage (e.g., branch breakage or tissue death) to whole-colony dislodgment. However, the bombardment process is poorly understood, given that it is difficult to observe in situ as hydrodynamic disturbances occur. Using 3D coral scans representing five characteristically different growth forms and finite element analysis, I simulated bombardment scenarios by applying increasing point forces to colony meshes. I measured the force required to cause breakage and where that breakage occurred, and found high rates of intra-colony breakage (a mean of 23% across growth forms). There was a significant interaction between colony surface area to volume ratios (SA:V) and the damage outcome (branch breakage or whole-colony dislodgement), but generally the impact force necessary to result in damage decreased as SA:V increased. Traditional models of coral damage during storms only consider hydrodynamic force, however, the results presented here show that bombardment may be the dominant process damaging and killing reef corals during hydrodynamic disturbances.

History

Notes

At foot of title: Quantitative Ecology and Evolution Lab, Department of Biological Sciences. Empirical thesis. Bibliography: pages 20-23

Awarding Institution

Macquarie University

Degree Type

Thesis MRes

Degree

MRes, Macquarie University, Faculty of Science and Engineering, Department of Biological Sciences

Department, Centre or School

Department of Biological Sciences

Year of Award

2016

Principal Supervisor

Joshua Madin

Rights

Copyright Peter A. David 2016. Copyright disclaimer: http://mq.edu.au/library/copyright

Language

English

Extent

1 online resource (34 pages) illustrations

Former Identifiers

mq:69085 http://hdl.handle.net/1959.14/1250562