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Description:
Author(s):
Gray, S. C., Sears, W., Kolupski, M. L., Hastings, Z. C., Przyuski, N. W., Fox, M. D., DeGrood, A.
Title:
Factors affecting land-based sedimentation in coastal bays, US Virgin Islands
Publication Date:
2012
Proceedings Title:
Proceedings of the 12th International Coral Reef Symposium, Cairns, Australia, 9-13 July 2012
Page(s):
5
Abstract:
"In the US Virgin Islands, land-based sources of pollution including sediment and storm-water runoff are one of the primary causes of coral reef degradation. Watershed development, especially the building of dirt roads, has increased the land-based (terrigenous) sediment accumulation in coastal bays with coral reefs. From 2008-2011, our research team and community partners have monitored marine sedimentation (using sediment traps) directly below developed watersheds (Coral Bay) and below undeveloped watersheds (Lameshur Bay) for comparison. These data suggest that total and terrigenous sediment trap accumulation rates below the developed watersheds were significantly higher than below undeveloped watersheds. The highest rates of terrigenous sediment accumulation occurred when there were periods of significant terrigenous runoff linked to major storm events, such as Hurricane Otto in October of 2010. Episodically high sediment accumulation rates on some reefs during storm events were consistent with rates shown elsewhere to cause stress to corals (>50 mg/cm2/day). Outside of storm events, total and terrigenous sediment accumulation rates on the coral reefs were generally low (<10mg/cm2/day). Recently, (July, 2011) watershed sediment erosion control projects were constructed above our study sites in the developed watersheds. In the future, temporal comparisons of our pre-mitigation (baseline) (2008-2011) and post- mitigation (2011-13) data, complemented by spatial comparisons between areas below developed, undeveloped and mitigated watersheds may provide data to inform the development of Best Management Practices (BMP) applicable to other tropical islands."
Keywords:
Sedimentation; St. John; US Virgin Islands; Land-based pollution; sediment traps
Electronic Access:
Notes:
NOAA CRCP grant NA10NMF4630065
Grant Number(s):
NA10NMF4630065
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