Is it possible to predict which areas of Bonaire are more susceptible to coral bleaching?

Bleaching is caused by the combination of light and temperature stress on corals, and can result in coral mortality. On the island of Bonaire, a monitoring program continuously records light and temperature data at 13 sites along the leeward shore of the island. In order to predict where bleaching would occur a light and temperature index was developed. Natural rages of temperature and light were determined from the monitoring program. Ranges were coded and codes were multiplied to calculate the index. Four sites were chosen. Two that were assumed to be impacted by anthropogenic modifications and two sites where there is little modification of the shoreline. Corals at the four sites were surveyed for bleaching three times during October, and then compared to the index, which was a mean of six values from the two weeks prior to sampling. Impacted sites were hypothesized to have the highest index numbers due to anthropogenic influences. However, a higher index corresponded to a lower percentage of bleaching. Impacted sites did not seem to have a significantly higher amount of bleaching then at low-impacted site. An interesting trend is noted in light levels that may be related to runoff or nutrient addition. The prevailing current along the west coast of Bonaire is from south to north. Light levels at 12 m and 20 m decreased from a high at the southern most site.

This student research was retrieved from Physis: Journal of Marine Science IV (Fall 2008)19: 40-44 from CIEE Bonaire.

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