Researchers, divers call Flower Garden Banks an underwater Texas treasure
Deep in the crystal blue waters of the Gulf of Mexico, 115 nautical miles from Galveston and 60 feet below the surface, a chain of gemlike coral rest atop ancient salt domes to create an oasis for marine life.
A national marine sanctuary since 1992, the Flower Garden Banks is the northernmost coral reef in the Western Hemisphere and, unlike many reefs worldwide, it’s largely robust and growing.
“It’s an odd dichotomy because when you’re out in the open Gulf, on the edge of the continental shelf, the sanctuary is completely surrounded by oil and gas platforms made of concrete and steel,” said marine biologist Michelle Johnston. “But, dive down into the water, and suddenly you’re in a paradise.”
Johnston works for the National Oceanic and Atmospheric Administration, the federal agency responsible for protecting this area and 12 others like it in the United States.
An experienced biologist and master diver, Johnston is on site at least six times a year to monitor the health of the Flower Garden Banks and to assess potential threats.
Her workspace comes with a magical view.
“What strikes you first is the sheer amount of coral,” Johnston said. “It’s massive. There are coral heads as big as cars and there’s so much of it.”
The reefs are mostly made of hard corals, including brain coral and mountainous star coral in green, brown and yellow. Living among them are thousands of fish, at least 100 species, and a menagerie of crustaceans, sponges and plants in all sizes, shapes and colors.
“I’ve seen whale sharks, gentle giants that are 20 feet and longer, and I’ve held my breath when tiger sharks came cruising by, though I’ve never felt threatened,” Johnston said. “I’ve had very large manta rays swim right next to me; they like to play in the air bubbles.”
Also present are large schools of black and yellow striped baby French angelfish, bright yellow butterfly fish and the technicolor parrotfish with their beak-like mouths and playful personalities. There are resident sea turtles, the threatened loggerheads and the endangered hawksbills.
In the winter, Johnston has seen spotted eagle rays and schools of hammerheads, a memorable sight.
“When you see all this with your own eyes, you instantly know what a treasure it is, and you want to protect it,” she said.
Geologists say the reefs are at least 10,000 years old, though fishermen first sighted them in the late 19th century. From their vessels, they could see the colorful corals far below in the clear Gulf waters. To them, it looked like a flower garden, which is what they called it, and the name stuck.
Today, the sanctuary includes the East and West Flower Garden Banks and the smaller Stetson Bank, added in 1996 and which lies 70 miles northeast.
Oddly, the reefs are where they ought not to be, said Kelly Drinnen, who works as an educator for the National Oceanic and Atmospheric Administration.
“The Gulf is about 500 feet deep in the area, much too deep for coral to survive, were it not for the enormous salt domes,” Drinnen said.
Millions of years ago, the Gulf of Mexico was a shallow sea. The climate was hot and, because of evaporation, there was a thick layer of salt on the sea bottom. As the Gulf deepened, silt and sand and river sediment accumulated on top of the salt layer. Pressured by these heavier materials, the salt deposits pushed upward, eventually forming large domes 60 feet or more below water.
“On top of the domes, it was possible for certain kinds of hard corals to grow and thrive,” Drinnen said.
For Texas divers, the Flower Garden Banks has been a draw for decades, but it takes time to get there — at least seven hours — and it’s a deeper descent than most.
Despite its remote location, local diver Mike McCroskey has spent years exploring the Flower Garden Banks.
“If you have the right conditions, it’s wonderful,” McCroskey said. “It’s peaceful and calm. You can see things you wouldn’t see in other parts of the world. Most of the corals are hardier species than you see in the Caribbean and there’s a lot of it. I’ve seen very large angelfish, triggerfish and rays. I’ve seen a whale shark right in front of me and at night, an octopus.”
Another local diver, Mike Magliolo, a physician, has been underwater all over the world, but he has had some memorable experiences in the Texas sanctuary, he said.
“There’s no question it’s a Texas treasure, but it’s not a dive for novices,” Magliolo said. “The currents can be swift and powerful over the domes and diving can be perilous if the weather changes.”
On one trip, after hours of traveling to get to the Flower Garden Banks, the weather turned and there were 8-foot swells. Everyone got sick and Magliolo’s group had to turn around and head back to Galveston, he said.
“It’s a long boat ride, so take good reading material,” Magliolo said.
In the summer months, the weather and conditions tend to be calmer, but whenever you’re planning to go, be prepared, he said.
The importance of coral reefs to the human world goes beyond their beauty as a natural wonder.
“Coral reefs support fisheries,” Johnston said. “They provide a place for juvenile snappers, groupers and yellowtail to feed and grow, and reefs close to shore act like a speed bump providing coastal protection during storms.”
Reefs are a microcosm of the underwater ecosystem. If a reef is healthy, that part of the ocean is healthy, too.
“When you see declining fish species, you know something is not right,” Johnston said. “It’s our early warning system.”
Why the Flower Garden Banks remain healthy as other reefs face deterioration is not entirely understood, but there’s probably a combination of factors at play, researchers say.
“It’s deeper, so the water stays cooler,” Johnston said. “It’s far from the coastline, so runoff and pollution is less of a problem. Also, there aren’t a lot of people, even though we encourage divers and fishermen.”
In many ways, the sanctuary is a sentinel site, Johnston said.
“This is what a healthy reef looks like,” she said. “We have about 52 percent coral cover; worldwide reefs are about 10 percent.”
Still, there are challenges to protect the area and potential for calamities.
In 2016, ocean temperatures soared upward of 87 degrees and stayed there for more than 90 days — a highly stressful event for corals, which began to evict their algae.
“Algae and coral have a symbiotic relationship that provides sustenance for both,” Johnston said. “When the algae are gone, the coral turns pale from a lack of nutrients, a process called bleaching.”
Bleaching is a worldwide problem because if the process does not reverse, the coral will die.
“In 2016, we did have bleaching,” she said. “It took time, but once the waters had cooled, most of the coral were able to recruit new algae and return to health.”
In a separate, unexplained event, there was a sudden die-off at the East Flower Garden Bank last year. The corals that were affected are completely dead and will not recover.
Scientists have theories about what happened, but it’s still a mystery.
“Low oxygen concentration was a factor, but it could be a cause or an effect,” she said.
A more immediate threat to the native fish living on the reef is overpopulation by an invasive species of lionfish. Johnston is leading an effort to keep them at bay.
“Lionfish are native to the Pacific and they look unusual,” she said. “Even our predator fish stay away from them. Because they have a voracious appetite and prey on our native species, and with no predator to check their proliferation, we have too many.”
This summer, there will be lionfish removal dives, where volunteers will extract as many specimens as possible.
The biggest challenges are long-term.
As the oceans warm and sea levels rise, there is potential for more frequent and powerful storms, changes in ocean currents, and rising pH levels, Johnston said. The pH scale is used to measure acidity or alkalinity.
But it’s not all doomsday.
“There is a lot of research going on around the world for sustainable, renewable resources that can diminish our carbon footprint,” she said. “Everyone has a role helping to save the world’s underwater wonders. It really does matter, so do your part: recycle, use non-toxic cleaners in your home and eat sustainable seafood.”
For information on the Flower Garden Banks National Marine Sanctuary, including volunteer dive opportunities, visit flowergarden.noaa.gov or attend the special World Oceans Day presentation at Moody Gardens in Galveston titled “Chasing Coral,” a documentary highlighting bleaching on the Great Barrier Reef in Australia and followed by discussions by National Oceanic and Atmospheric Administration staff on the Flower Garden Banks sanctuary.