ESRL/PSD Seminar Series

Abstract

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Coral reefs cover approximately 2.8 to 6.0 x 105 km2 of the Earth¢s surface and are a major source of heat and moisture to the atmospheric boundary layer. Consequently, the shallow warm waters overlying coral reefs may influence cloud field properties, local winds, rainfall and cyclone genesis. However, the complexities of making micrometeorological measurements over coral reefs have long been a deterrent to researchers. As a result, there remains a dearth of information on air-sea energetics over coral reefs and their role in carbon budgets.

In this presentation I will discuss recent advances in understanding of coral reef-atmosphere energetics and exchanges of CO2. These have been achieved through development of novel pontoon mounted Eddy Covariance systems deployed over Heron Reef on the southern Great Barrier Reef, Australia. Results show that under most situations > 80% of net radiation over Heron Reef is partitioned into heating the water column, benthos and substrate. As result, under clear summer conditions with low wind speeds, turbulent flux exchange with the atmosphere is suppressed causing intense heating of the water overlying the reef, particularly during midday low tides causing coral bleaching. Measurements of CO2 exchanges show that the reef is a net sink rather than acting as a source of atmospheric CO2.

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