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Purpose : To study the current patterns in Hurricane Hole and their possible affect on the variation in distribution and abundance of corals growing on the roots of mangrove trees in the four inner bays. . Results. Results. Equipment. Hydrolab. Drifter Trajectories in Hurricane Hole. - PowerPoint PPT Presentation
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Biophysical influence on coral abundance and diversity in Hurricane Hole, St. John, United States Virgin IslandsSophia McKenzie, Nasseer Idrisi, Caroline Rogers, Vanessa Wright, and Laurent Cherubin
University of the Virgin Islands
Purpose: To study the current patterns in Hurricane Hole and their possible affect on the variation in distribution and abundance of corals growing on the roots of mangrove trees in the four inner bays.
Hydrolab Measures temperature: can be
used to determine flow
Current MeterMeasures speed and direction of bottom currents
Four observations per day during current meter deployment (12/2/2010 – 1/31/2011)
Drifter Trajectories in Hurricane Hole
West Mid East Inner Bays Mouth
Wind Speed (m/s) and DirectionDuring Drifter Trials
Methods
Equipment
Acknowledgements Thanks to Jon Moore, Shaun Kadison, Shawn, Kevin Brown, Joanna Gyory, James Herlan, USGS, and EPSCoR for your support. References C.S. Rogers, USGS, personal observation, 2005.
Conclusions• Wind driven current• Onshore surface flow and offshore bottom flow indicative of downwelling• Inner bays protected from wind• Current does not explain high coral abundance in east bays• Other factors at work determining coral abundance• Temperature and water chemistry likely to affect coral abundanceThrough continued study of Hurricane Hole, we hope to better understand the mechanisms by which corals are thriving in an environment typically not suitable for their survival.
Borck
Princess
Otter
Water
1
1
1
2
2
2
3
3
3
4
4
4
Borck Princess Otter Water27.627.727.827.9
2828.128.228.328.428.528.6
InnerMidOuter
Tem
pera
ture
(°C)
1 2 3 426.5
27
27.5
28
28.5
29
29.5
30
HH MouthCoral Bay Inner MouthCoral Bay Outer Mouth
Location
Tem
pera
ture
(°C)
Inner Bay Temperatures
Note: Inner locations are closest to shore
Mouth Temperatures
Hurricane Hole Mouth
Coral Bay Outer Mouth
Coral Bay Inner Mouth
Clusters• Northwest movement• Angles of tracks correspond with variation in wind speed • Wind showed small south component during trials
Transects• Borck ,Water, and most Princess drifters moved southwest• Southeast direction for inner Princess•Mouth and Otter moved directly east
Current Meter
Average CurrentSpeed: 0.0424 m/s
Variance: 0.0260 m/sDirection: 159.21°
(southeast)
Results Results
Hydrolab
0.0079 m/s
0.0739 m/s
0.0979 m/s
West Cluster Mid Cluster East Cluster Inner Bay Transects Mouth Transect
Drifter Cluster Release Current Meter Hydrolab Cast
