Do seagrass beds enhance coral calcification? Comparing growth of nursery-reared Acropora cervicornis on a seagrass bed and patch reef.

Seagrass beds are an important natural resource in South Florida. They act as a refuge for many juvenile fish species, filter and stabilize sediments and act as protective barriers to surrounding coral reefs. Previous studies have suggested that benthic habitats that exhibit high rates of photosynthesis can alter the seawater chemistry in such a way that they could provide improved conditions for calcification of downstream reefs. The growth rates of nursery-reared Acropora cervicornis were compared between fragments transplanted on a seagrass bed and a patch reef near the University of Miami’s Broad Key Research Station. Coral growth (mg/day) was significantly higher at the patch reef vs. the seagrass bed for the two study periods (Oct-Dec 2011 and Dec 2011-March 2012). Additionally, aragonite saturation states were not significantly different between sites, leading to the conclusion that other factors, such as grazing, sedimentation, nutrient retention, and algal growth, are likely influencing coral growth rates. Thus, based on these findings, seagrass beds are not an ideal site for coral growth and should not be utilized as nursery habitats.