Abstract

Impacts from climate change on coral reefs are outpacing our ability to protect these important ecosystems. Practical approaches to reduce temperature and light stress to corals during summer bleaching events are greatly needed. The Keys Ocean Rangers (KOR) received the first Ocean Innovation Award from the Gulf and Caribbean Fisheries Institute to develop and test a number of potential technologies that may one day help managers on the ground better respond during periods of peak bleaching stress. In phase one, we designed, tested, and compared several innovative technologies to reduce water temperatures, reduce solar irradiance reaching corals, and increase mixing and oxygenation of the water column. The engineering systems we tested included: i) Aeration through bubbler and airlift systems, ii) Sprinklers and misters, and iii) Shade cloths. We conducted experiments in a 14,000 gallon pool then scaled up to a saltwater quarry (in excess of several million gallons). Each test measured physical parameters that are an indication of environmental conditions that contribute to stress on corals: light intensity, daily solar heating, water temperature, and water flow/circulation. Each technology was also evaluated for its costs, feasibility for field deployments, and stand-alone capability. Two of these technologies which showed the greatest net benefits, shading and aeration, were then scaled up and tested during phase 2 in an enclosed salt water quarry for their influence on temperature and light stress. Results suggest that combining shading and aeration provides the greatest stress reduction during bleaching events and is feasible with easily available components for areas up to 10mx10m areas and water depths of up to 12 m, with the ability to scale up. While further development and testing of aeration and shade systems for reefs are underway, we hope this pilot feasibility study and the vision of GCFI’s Ocean Innovation Award’s purpose

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