Manzello, D. P., Enochs, I. C., Melo, N., Gledhill, D. K., Johns, E. M.

Ocean acidification refugia of the Florida Reef Tract

2012

Rosenstiel School of Marine and Atmospheric Science, University of Miami; NOAA, Atlantic Oceanographic and Meteorological Laboratories; NOAA Ocean Acidification Program

PLoS ONE

7

7

"Ocean acidification (OA) is expected to reduce the calcification rates of marine organisms, yet we have little understanding of how OA will manifest within dynamic, real-world systems. Natural CO2, alkalinity, and salinity gradients can significantly alter local carbonate chemistry, and thereby create a range of susceptibility for different ecosystems to OA. As such, there is a need to characterize this natural variability of seawater carbonate chemistry, especially within coastal ecosystems. Since 2009, carbonate chemistry data have been collected on the Florida Reef Tract (FRT). During periods of heightened productivity, there is a net uptake of Total CO2 (TCO2) which increases Aragonite Saturation State (Omega-arag) values on inshore patch reefs of the upper FRT. These waters can exhibit greater Omega-arag than what has been modeled for the tropical surface ocean during preindustrial times, with mean (plus or minus std. error) Omega- arag values in spring = 4.69 (plus or minus 0.101). Conversely, Omega-arag values on offshore reefs generally represent oceanic carbonate chemistries consistent with present day tropical surface ocean conditions. This gradient is opposite from what has been reported for other reef environments. We hypothesize this pattern is caused by the photosynthetic uptake of TCO2 mainly by seagrasses and, to a lesser extent, macroalgae in the inshore waters of the FRT. These inshore reef habitats are therefore potential acidification refugia that are defined not only in a spatial sense, but also in time; coinciding with seasonal productivity dynamics. Coral reefs located within or immediately downstream of seagrass beds may find refuge from OA."

National Coral Reef Monitoring Plan (NCRMP); climatic monitoring

10.1371/journal.pone.0041715

FY2013 CRCP Project ID 743; Project Title: National Coral Reef Monitoring Plan (NCRMP) Implementation (Climatic Monitoring); Principal Investigator: Jessica Morgan