Greg McFall estimates he has made more than 500 dives at Gray’s Reef National Marine Sanctuary, about 17 miles east of Sapelo Island.
It never gets old, he said.
“This place is so unique and so diverse. On every single dive I make here, I see something I’ve never seen before,” said McFall, deputy superintendent and research coordinator for the 23-square-mile sanctuary. “That happens every dive.”
The diversity is in part due to ocean currents. Since the reef is at the crossroads of warm water from the gulfstream and colder water from up north, it brings in sea life from both temperate and tropic zones, making it a marine melting pot of sorts.
Biologists say they know of more than 800 species that call the waters around Gray’s Reef home — including a new species of sea squirt named after the Georgia Southern graduate student who found it in 2004 — but there could be thousands of living organisms yet to be identified.
It’s that diversity and abundance that makes the sanctuary not only a playground for divers and recreational anglers, but also an ideal laboratory.
Recently, biologists from Gray’s Reef, the National Oceanic and Atomospheric Administration and Georgia Southern spent time on the NOAAS Nancy Foster to look at areas set aside in December for research and restricted to all fishing and diving, and compare them to areas within the sanctuary still open to recreational use.
“As far as I know, there’s never been an area set aside that was never previously used only for sport fishing like Gray’s Reef,” said Daniel Gleason, a biology professor at Georgia Southern who is studying invertebrates — sponges, sea squirts, corals and other species — at various sites around the sanctuary floor.
While Gleason and his colleagues try to catalogue and identify what’s at the bottom in the 60-foot depths at Gray’s Reef, NOAA biologist Roldan Munoz is studying the fish in the habitat from gag grouper to a newcomer known as the lionfish, a ravenous intruder with an appetite which may or may not present a problem to native species in coming years.
Tying in how the vertebrates and invertebrates coexist is part of the study, but biologists know that fish won’t thrive without the invertebrates that populate Gray’s Reef.
“The reefs themselves are essential fish habitat,” Munoz said. “It’s an area we know the fish need to live and to carry out their lifecycles.”
What biologists such as Gleason and Munoz hope is that by studying an area where Gray’s Reef is left undisturbed, they can better understand the bigger picture.
“In some cases, rather than trying to understand things completely, it can be beneficial to have a reference site and see what the environment does on its own,” Munoz said. “That can be a very powerful tool.”
Yet those charged with protecting and studying Gray’s Reef also want public input, McFall said. The sanctuary continues to undergo review of its management plan — a process in which “public input is a very critical and important aspect of what we do,” he said.
“We’re trying to connect the people who live in this geography to the sanctuary through outreach events such as Earth Day events, open houses and film festivals,” McFall said. “We encourage people to come and ask us questions.”
Scientists study the sanctuary year round, trying to understand everything from warming ocean temperatures and acidification to how sediment and pollutants from rivers such as the Ogeechee and Altamaha impact Gray’s Reef.
But the annual visit of the Nancy Foster, a converted World War II torpedo tester now used for a number of scientific missions around the east coast, Caribbean and Gulf of Mexico, allows biologists and other scientists a platform from which dive down to Gray’s Reef and study its inhabitants up close. That view continually offers up something to inspire even veteran scientists..