At an underwater coral nursery off the lower Florida Keys, scientists are growing cuttings of staghorn coral (Acropora cervicornis) for reef restoration. Staghorn coral was, until recently, a major reef building species throughout the Caribbean. However, since the late 1980’s, populations have declined up to 97%, resulting in it being designated a threatened species in 2006.
Scientists are interested in the amount of light in the nursery because coral needs a lot of light. Corals are found in tropical areas because the combination of tropical sun and clear water allows a lot of light to reach them. Some scientists theorize that increased amount of sediment in the near shore ocean waters has resulted in a decrease in the amount of sunlight reaching the reefs.
In this nursery, an optologger is being used to record the light level. Housed in a waterproof case, it sits about 30 feet deep on the ocean floor. Connected to an Apogee AQ-110 quantum sensor, it records the light intensity once a minute. Divers periodically retrieve the system to download data and clean the light sensor.