thumbnail

Wave- and tidally-driven flow and sediment flux across a fringing coral reef: Southern Molokai, Hawaii

Continental Shelf Research

By:
, , , ,
DOI: 10.1016/j.csr.2004.02.010

Links

Abstract

The fringing coral reef off the south coast of Molokai, Hawaii is currently being studied as part of a US Geological Survey (USGS) multi-disciplinary project that focuses on geologic and oceanographic processes that affect coral reef systems. For this investigation, four instrument packages were deployed across the fringing coral reef during the summer of 2001 to understand the processes governing fine-grained terrestrial sediment suspension on the shallow reef flat (h=1m) and its advection across the reef crest and onto the deeper fore reef. The time-series measurements suggest the following conceptual model of water and fine-grained sediment transport across the reef: Relatively cool, clear water flows up onto the reef flat during flooding tides. At high tide, more deep-water wave energy is able to propagate onto the reef flat and larger Trade wind-driven waves can develop on the reef flat, thereby increasing sediment suspension. Trade wind-driven surface currents and wave breaking at the reef crest cause setup of water on the reef flat, further increasing the water depth and enhancing the development of depth-limited waves and sediment suspension. As the tide ebbs, the water and associated suspended sediment on the reef flat drains off the reef flat and is advected offshore and to the west by Trade wind- and tidally- driven currents. Observations on the fore reef show relatively high turbidity throughout the water column during the ebb tide. It therefore appears that high suspended sediment concentrations on the deeper fore reef, where active coral growth is at a maximum, are dynamically linked to processes on the muddy, shallow reef flat.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Wave- and tidally-driven flow and sediment flux across a fringing coral reef: Southern Molokai, Hawaii
Series title:
Continental Shelf Research
DOI:
10.1016/j.csr.2004.02.010
Volume
24
Issue:
12
Year Published:
2004
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
1397
Last page:
1419
Number of Pages:
23