Coral reef ecosystems near the coast are often introduced to freshwater, nutrients, and pollution from nearby rivers and lakes. In Florida, the northern section of the Florida Reef Tract is near the mouth of the St. Lucie River, which has been used to reduce rising water levels from neighboring Lake Okeechobee. The river empties into the St. Lucie estuary and the Florida Reef Tract, bringing large amounts of freshwater (known as plumes) and high levels of nutrients into the reef ecosystem. This plume can negatively affect water quality on the reef by promoting phytoplankton blooms and changing carbonate chemistry which is critical for hard coral development.
The group collected water samples during the rainy season in late summer 2015 and the dry season in spring 2016, from both the St. Lucie estuary and the reef area, to examine levels of carbonate, nutrients, and chlorophyll.
The group also developed a computer model that created a three-year simulation of the physical and biogeochemical aspects of the St. Lucie River plume, from 2013 to 2015.
The combined results showed that the St. Lucie River plume greatly affects the water quality of the nearby coral reef ecosystem by supporting phytoplankton blooms, as well as by heavily influencing the carbonate chemistry. The study brings a better understanding of the complex relationship between freshwater plumes and coral reef health in Florida, and can provide better insight into how to best manage land-based sources of pollution to conserve coral reefs.
The NOAA Coral Reef Conservation Program was established in 2000 by the Coral Reef Conservation Act. Headquartered in Silver Spring, Maryland, the program is part of NOAA's Office for Coastal Management.