The Florida Middle Grounds are a succession of ancient coral reefs 1,193 square km in area located in the northeastern Gulf of Mexico, approximately 80 miles west northwest of the West coast of Florida. These reefs consist of a series of both high and low relief limestone ledges and pinnacles that exceed 50 feet in some areas. Roughly 348 NM2 of this hardbottom region 150 km south of the panhandle coast and 160 km northwest of Tampa Bay between 28° 10' and 28° 45' N and 084°00' and 084°25' W is considered a habitat area.[1]
The Florida middle grounds evolved approximately 20,000 years ago when ocean levels were much lower and sunlight was available to corals. As the ocean level increased it outpaced abilities of certain coral species to extract the necessary light spectrum from the suns rays.
Today’s middle ground reef ecosystem represents the northern most scope of mid-shelf octocoral communities in North America. It is a prehistoric coral-reef complex that has bio-similarities to modern patch-reefs, and a species distribution that includes both Carolinian and Caribbean components. The fish species are markedly tropical, with stony coral, gorgonians, and sponge dominating the community that relies upon the existence of the Loop Current. Currently, there are 170 species of fish, 103 species of algae, approximately 40 sponges, 75 mollusks, 56 decapod crustaceans, 41 polychaetes, 23 echinoderms and 23 species of stony corals.[2]
In 2000, a research project was funded by the National Oceanic and Atmospheric Administration to evaluate the status of the reef.[2] This research was conducted utilizing the DeepWorker 2000 one person submersible.[3]
The "Middle grounds shipwreck" is a popular scuba diving and fishing location. In 2004, the wreck was identified by a team of divers led by Michael C. Barnette as the tugboat Gwalia.[4][5]