Almost one hundred feet under the sea, I was flying. I glided through a seascape of vibrant corals and tropical fish, inspecting the reef’s caves and nooks with childlike curiosity. I crossed a sandy area toward an emerald hillock, pushed my flippered feet downward, and hovered vertically—the coral before me was massive and majestic. Spinning slowly in a circle, I took in the matriarchs and patriarchs that surrounded me: enormous amber colonies as well as limestone thrones overlaid in jade-green clusters. To explore a grove of these ancients, possibly dating back 1,500 years, felt like hiking among the redwoods in Northern California. Some scuba divers venture to this place for the manta rays as big as living-room carpets and whale sharks the size of school buses. But for me, these grand corals were the true giants. 

The first time I heard of Flower Garden Banks—years ago, when I was an ocean scientist—it sounded like a Texas-size tale: a collection of seamounts rich in coral, rising from waters hundreds of feet deep, about a hundred miles southeast of Galveston. Not a flimsy, raggedy reef, but one bursting with life. A spectacular dive site with waters as crystalline as those at the most sought-out locations in the world, like the Indo-Pacific’s Coral Triangle or Australia’s Great Barrier Reef, with visibility that stretched a hundred feet or more. A place where behemoths roamed: all those manta rays and whale sharks, as well as giant grouper like the ones you might see in faded photos on the walls of tackle shops, and schools of hammerhead and blacktip sharks. All of this just a few hours off the Texas coast. The story seemed preposterous. 

As my career shifted to science writing, I let Flower Garden Banks slip from my imagination. Even when I decided to write a book about the world’s disappearing coral, spending the past three years traveling to reefs from the Dominican Republic to Indonesia, I left that story—the one closest to home—unexplored. But on January 19 of this year, the last full day of the Trump administration, the federal government announced it was nearly tripling the size of Flower Garden Banks National Marine Sanctuary by adding fourteen more reefs and banks to its boundaries. If a protected area, already 56 square miles amid some of the world’s richest oil and gas reservoirs, could be expanded by a president who had rolled back nearly a hundred environmental regulations in one term, I knew that this place must hold ineluctable power. 

Flower Garden Banks contains some of the healthiest remaining coral reefs on the planet. Yet most Texans, even those who are avid scuba divers, haven’t heard of it. The reason these lively underwater habitats have evaded attention for so long is that they are farther from shore than most reefs and are located deeper than those preferred by occasional divers and snorkelers. Those same attributes have also helped preserve Flower Garden Banks. But like all coral environments—which are predicted to almost disappear by 2050—these reefs face threats from climate change, disease, and invasive species. In an effort to save Flower Garden Banks from such perils, an unlikely group of bedfellows worked together for more than a decade to build something almost as rare these days as the reefs themselves: progress through compromise. 

A diver swimming over an ancient coral colony.
A diver swimming over an ancient coral colony at East Flower Garden Bank on June 14.Photograph by Ben Lowy

Two hundred million years ago, when the supercontinent that geologists named Pangaea split in two, a nook appeared, like the curve of your fingers and thumb encircling a cold beer. That nook, the fetal Gulf of Mexico, held a sea brimming with microscopic marine creatures. When they died, they sank to the floor, forming the carbon-rich deposits that would eventually help make Texas the tenth-largest economy in the world, if it were a country. Meanwhile, Earth warmed and cooled over and over, impounding water in ice and then releasing it to the seas. When the seas rose, they flooded the nook. When they fell, the water evaporated, but the salt remained; eventually, the basin was coated by a saline layer more than two miles deep in parts, sealing the remains of those animals in place.

About a hundred million years later, the watershed of the nascent Mississippi River began washing sediments off the young North American continent. The sediments grew thick—as much as six miles deep—and heavy. Under this added pressure, the salt became pliable and pushed up through cracks in the more brittle sections. Technically, these geologic features are called diapirs, a French word likely derived from the Greek diapeirein, meaning “to pierce through.” In Texas, we usually call them salt domes.

A belt of hundreds of salt domes formed along the edge of the continental shelf, stretching from what is today the Florida-Alabama border to South Texas. As the sea level stabilized with the retreat of the last glaciers, the tops of most of those domes remained hundreds of feet below the sea’s surface. But others reached within just dozens of feet, where sunlight could filter down. 

Like all seas, the Gulf of Mexico is dominated by a particular current; this one is called the Gulf Loop Current. Starting in the gap between Cuba and the Yucatán Peninsula of Mexico, a current of warm seawater flows northward into the Gulf, makes a clockwise half-turn, then heads back out through the gap between Cuba and Florida, joining up with the Atlantic’s Gulf Stream. The Loop Current sometimes makes a tight U-turn around Cuba and other times moves deeper into the Gulf, swooping all the way to Brownsville and swinging east along the belt of salt domes before heading back out to the Atlantic. 

At least 10,000 years ago, it’s believed, some lucky coral larvae, minuscule, Tic Tac–shaped bits of life, were birthed in the Yucatán. They hitched a several-hundred-mile ride on the Gulf Loop Current to what is now Flower Garden Banks. I try to envision them—not just one species of coral but two dozen—somehow evading the hordes of hungry shrimp and fish along the way, improbably finding the tops of shallow salt domes, where energy from the sun made all the difference to those larvae and to the future of Flower Garden Banks.

Power in its many forms—political, economic, and environmental—has always played a pivotal role in the story of this place, both above and beneath the waves. 

Location of the Flower Garden Banks National Marine Sanctuary, map

To get to Flower Garden Banks, divers can book a shared or private charter for day trips or multiday visits from coastal towns in Texas such as Freeport, Sabine Pass, or Surfside; under perfect weather conditions, boats can reach the coral reefs in four or five hours. I reserved a mid-May voyage on the Fling, the only commercial dive boat that offers regular two- and three-day journeys to the sanctuary most of the year. Operated out of Freeport, 42 miles southwest of Galveston, by Sharon Cain and captain Ken Bush, the Fling has delivered wide-eyed explorers to Flower Garden Banks for thirty years. 

An unusually stormy February, March, and April dashed every weekend Fling excursion leading up to my trip. As my own outing approached, spring storms hurled themselves up out of the Gulf and across Texas, stirring waves as high as eleven feet. When Cain canceled our trip, two days out, she wrote on Facebook, “The Gulf is still very angry.” 

I rescheduled a three-night tour in mid-June and crossed my fingers for calmer waters. With the exception of tanks of compressed air, the Fling requires that everyone bring their own equipment. As inoculations made travel possible again, dive shops were swamped with Texans ready for adventure. Classes were full, gear already rented. I finally found what I needed at one store, where, when I mentioned my trip to Flower Garden Banks, the clerk warned, “You know that’s not a place for beginners.” I knew, and it worried me. 

Out in the middle of the Gulf, currents can be strong and fast-shifting. The shallowest of the dives at Flower Garden Banks are sixty feet, with most a hundred feet or deeper. I took a class to learn about nitrox so that I could be prepared to breathe compressed air with a lower-than-usual nitrogen content, which is recommended for dives between fifty and a hundred feet. It would be my first time diving with mixed gases. I’ve been that deep only once, not long after I first started diving, almost thirty years ago. 

Planted on the seafloor and bearing colorful halos of petallike tentacles, coral might resemble flowers, but they are animals. Each colony is a collection of pencil eraser–size, sea anemone–like polyps connected by a thin layer of tissue. Their homes are elaborate, filigreed skeletons built upon the skeletons of their ancestors.

While it is a defining trait of animals—including us—to eat our fuel, coral don’t. Or not very much. They are mostly solar-powered animals. Their alternative-fuel engines are single-celled algae that live inside coral tissues. Like all plants, algae photosynthesize; they feed the coral more than 70 percent of the sugar they make. The sugar turbo-charges the coral, providing enough energy to construct their limestone reefs. Coral grow on the shallowest of the Gulf’s salt domes because there is enough light there to drive their algal engines.

In the early 1900s, snapper and grouper fishermen looked down from the decks of their boats into that sky-blue water, where it wasn’t hard to see the colorful tops of salt domes. They named the spot “Texas Flower Gardens” for its vibrant floral appearance and returned to shore with reports that bits of coral were often entangled in their nets. Skeptics, however, thought the specimens were fossils.

Divers, including Robert Woods (far left), preparing to jump in at Flower Garden Banks in 1967.
Divers, including photographer Robert Woods (second from left), preparing to jump in at Flower Garden Banks in 1967. Courtesy of Robert Woods/World Book

Until the mid-twentieth century, scientists didn’t take the claims of coral reefs in the deep Gulf seriously, but Tom Pulley, director emeritus of the Houston Museum of Natural Science, believed the fishermen’s stories. In 1960 he asked the Navy to loan him a destroyer headquartered in New Orleans. He assembled a team of divers who, in those days before neoprene and silicone, geared up in khaki pants and Speedo-style swimming trunks. During their descent to the tops of the salt domes, they dodged barracuda and sharks. On the way up, they carried more than a thousand pounds of living coral and sponges. One of those divers, photographer Robert Woods, participated in another big expedition at the site seven years later, this time bringing back photographs of fire and brain coral, of grouper and butterfly fish. There was a coral reef in Texas, and it was very much alive.

The Bureau of Land Management, the federal agency responsible for regulating Gulf oil and gas leases at the time, wanted reconnaissance on these newly discovered reefs. In the early seventies, it tapped Tom Bright, a marine scientist at Texas A&M University who is now regarded as the father of Flower Garden Banks. He acquired a two-person submersible for those initial exploratory dives. “The little submarine would go down to six hundred feet,” he said, speaking to me from Idaho, where he’s now retired. “We crawled into it and made transects across all the banks. The result was a description of the biotic communities.”

On salt domes too deep for reef-building coral, Bright discovered that enough light filtered down for another kind of photosynthetic life. Called coralline algae, they look like the olive and copper lichens covering granite walls throughout the Texas Hill Country, but in colors of carnation pink and eggplant purple. “Not only do they encrust the existing reef rock and bind it all together,” Bright said, “they form these algal nodules that are scattered about almost all these banks down to about two hundred and fifty feet.” These nodules build the architecture for a bustling suburbia surrounding the coral cities. “The diversity on these algal nodule terraces may be equally high or possibly higher than on the coral reefs in terms of number of species of animals,” he added. “That’s where a lot of the action is.”

Petroleum geologists were attracted to salt domes as places to drill for oil. When a diapir pushes through the overlying layers of sediment, those layers deform. Hydrocarbons, which are lighter than the surrounding briny water, migrate upward. They continue rising until they are hemmed in by something impermeable, like a balloon hitting the ceiling. In the Gulf, that ceiling—or, to use the technical homonym, the sealing—is frequently salt. Oil and gas reservoirs often abut a salt dome. 

In 1938 the first oil and gas platform in offshore Gulf waters was installed near Creole, Louisiana. Over the next forty years, thousands more sprouted in deeper and deeper waters, forming what’s been called a “steel archipelago.” Aside from the salt domes, the seafloor in the Gulf is soft and silty—a shifting, moonlike habitat. A platform in two hundred feet of water represents several acres of livable hard surface. For migrating animals, the platforms act as respite from the open sea. Small fish that find refuge there attract predatory species such as grouper, snapper, and sharks. Fishermen recognized the platforms as excellent angling spots. By 2008, 80 percent of the recreational fishing trips in the Gulf included visits to oil and gas platforms.

The National Marine Sanctuaries Act was passed in 1972, exactly one hundred years after Yellowstone became the first national park. Not long after that, a dive club in Houston submitted Flower Garden Banks as a candidate for the new federal program, which provided strong protections for valuable undersea environments.

Some in the oil and gas industry expressed concerns. They argued that many protections were already in place, which was true. Operations disturbing the coral habitats were forbidden. Mud from drilling couldn’t be discharged within a mile of the banks. Companies had to monitor ecosystem changes as part of lease agreements. Meanwhile, commercial fishing interests also worried they might be subject to new regulations. These tensions held up progress toward safeguards for Flower Garden Banks for a decade—until disaster struck. In 1983 a tugboat pulling a two-hundred-foot-long barge dragged a huge anchor across East Flower Garden Bank. A dive team monitoring coral health watched it happen. Those divers took video of a gouge in the reef that was about four hundred feet long, estimating it destroyed more than two hundred coral colonies. Although all harmful activities were supposed to be banned in Flower Garden Banks, bureaucratic confusion had let anchoring slip through the cracks. 

A staffer for then–newly elected Texas congressman Solomon Ortiz learned of the damage and informed the boss. Not long after the incident, Ortiz, a Democrat who represented a district that included Corpus Christi, introduced the Coral Reef Protection Act, which, if it had passed, would have imposed new restrictions in the Gulf. The possibility of such regulations gave a big push to the years-long effort to designate the area as a sanctuary. In 1992 a president with deep Texas connections, George H. W. Bush, formally designated Flower Garden Banks as a National Marine Sanctuary (five other marine sanctuaries were designated during his term, the most under any president). This move protected the East and West Flower Garden salt domes, at about 16,000 and 19,000 acres, respectively, and about twelve miles apart. In 1996 Stetson Bank, a 540-acre coral community located about 30 miles northwest of West Flower Garden Bank, was added, boosting the sanctuary’s size to about 56 square miles.

I struggled to sleep that first night amid the rumble of the engines, the rolling motion of the boat, and my anxieties about my first dive at these depths.

In mid-June, the Gulf finally calmed. My trip to Flower Garden Banks was on. Ahead of the 7 p.m. boarding time, the Fling emerged down the canal toward its dock in Freeport. A hundred feet long, with a marine-blue hull and white decks, it cut a handsome figure in the evening sun. The boat looked a bit less majestic up close. It was clean and in good condition, but the interior was vintage eighties, reflecting the era when it had been converted from a crew boat servicing oil platforms into a dive boat. In the bunkroom I shared with three others, I struggled to sleep that first night amid the rumble of the engines, the rolling motion of the boat, and my anxieties about my first dive at these depths. As the rocking intensified, I slipped out of bed before dawn. Entering the wheelhouse, I found Captain Dennis Gray at the helm. “We’re passing through a squall,” he said. The sun peeked above the horizon on the port side, as cracks of lightning lit up the silhouettes of oil platforms. I grabbed a cup of coffee in the galley and then stepped out the back door to the dive deck, where a light rain fell and the sky turned a deep crimson. A rainbow formed on a mauve background, giving the morning an otherworldly feeling.

After the squall passed, we readied ourselves for the first two dives in West Flower Garden Bank. The Fling’s dive masters jumped in first to scope out conditions and set rope lines for us to follow. Back on board, they reported the water temperature at 80 degrees Fahrenheit and the seafloor seventy feet down. The ropes would guide us to the edge of the reef; there, we could look off into the pelagic blue, where larger creatures often cruise. One of the dive masters had just spotted a manta ray there. 

I pulled on my full-length wet suit, buoyancy vest, air tank, and booties and awkwardly shuffled up to the opening in the Fling’s railing. I placed my breathing regulator into my mouth and happily discovered that nitrox tasted just like regular air. I pulled on my fins, gathered my depth and air-pressure gauges in one hand, held my mask and regulator with the other, and leaped into the sparkling water, rays of sunlight streaming through. Before I fully registered my thoughts—“It’s so warm! I can see so far!”—I reached the yellow guide rope and followed it down. 

I descended into a world rich with coral. Colonies in the form of massive plates abutted one another as far as I could see. There were no breaks for sand or algae, only fields of coral. A forest of Christmas tree worms blinked down into their paired holes in the colony beneath me, drawing my attention to the other creatures. In one frame of my mask, I spotted pastel parrotfish, wing-finned triggerfish, streamer-finned angelfish, and red-herringbone squirrelfish with enormous black-rimmed eyes. The coral cover was so great that where the colonies bumped up against one another, a turf battle raged. Like jellyfish, coral have stinging cells in their tentacles. Some of those cells are deployed against other coral, pushing back colonies that want to claim more territory. Given the demise in coral cover worldwide, it had been decades since I’d seen such boundary wars. Here, the battle-wrought margins signaled this reef’s exceptional health. 

The colonies were so big that even when I spread out my arms to approximate their measure, their edges stretched beyond my span. I thought, “I’m hovering over a colony of animals that’s a thousand years old.”

A blue angelfish framed by orange cup coral, which thrives on structures such as oil platforms and shipwrecks.
A blue angelfish framed by orange cup coral, which thrives on structures such as oil platforms and shipwrecks.Photograph by Ben Lowy

About a year after Flower Garden Banks’ 1992 designation as a national marine sanctuary, Emma Hickerson, a zoology undergrad at Texas A&M, was working in a dive shop in College Station. One day, a graduate student walked in and asked if Hickerson would be willing to count fish at a coral reef at Flower Garden Banks. A native Australian, Hickerson didn’t have high expectations about what she’d find, but she accepted. “It was amazing to have that introduction and fall in love with this place,” Hickerson told me. Five years later, the National Oceanic and Atmospheric Administration hired her to be the sanctuary’s research coordinator, overseeing all scientific activities at the banks. She still holds the job today. Now, after more than 1,200 scuba dives, she has learned more about the sanctuary’s undersea communities than most. 

Around 1998, the U.S. Geological Survey provided Hickerson with high-resolution maps that allowed her to begin identifying the diversity of life on the northwest Gulf’s reefs and banks. “It was so eye-opening because we now had a road map to the hard-bottom features—the lumps and bumps—that provide the habitat for the [various species]. It was like, ‘What lives at that bump?’ ” After sorting through thousands of images and developing codes for possible species, she scheduled a series of excursions to identify exactly what lived there. Today, that coral-reef monitoring program is one of the oldest in the world. The number of species identified so far in the shallower parts of the East and West Flower Garden Banks alone stretches to 47 pages and includes 23 species of reef-building coral, 259 species of fish, 56 species of sponges, 227 species of crustaceans, and 403 species of mollusks. She is now cataloging deeper sections as well as additional areas of the newly expanded sanctuary, which will include even more species.

One of the remarkable phenomena that the scientific work uncovered was that the reef-building coral in Flower Garden Banks typically spawn en masse once a year, in a coordinated nighttime orgy of eggs and sperm that turns the reef into a reverse snowfall of millions of minuscule, pinkish orbs that float up to be fertilized near the sea’s surface. Hickerson’s been making observations on the annual event for years, even developing a prediction calendar. “It’s seven to ten days after the full moon in August,” she said, adding that depending on lunar cycles, it can happen a second time in occasional years, after a September full moon. 

Clint Moore wasn’t the first person you’d have in mind to steer a group charged with expanding environmental protections in an area rich in petroleum.

The ongoing research confirmed Tom Bright’s early findings that the teeming life of Flower Garden Banks isn’t confined to the original three banks. Hundreds of studies using submersible watercraft, both autonomous and piloted, showed that algal nodule communities extended over dozens of domes with tops between about 150 and 250 feet beneath the surface, which serve as nursery grounds for commercially valuable fish such as red snapper and grouper. On domes down to around 500 feet, species of slow-growing black corals and octocorals shelter their own unique communities. Drawing a line around three banks within diving depth was arbitrary from an ecosystem point of view. It didn’t take into account what Hickerson called “habitat highways” among other reefs in the Gulf. Flower Garden Banks turned out to be part of a much larger system. By 2007, the findings showed that the stops along those highways deserved protections too.

The superintendent of Flower Garden Banks National Marine Sanctuary receives guidance from a group of sixteen voting members as well as six nonvoting representatives from government agencies (all currently based in Texas, save three in Louisiana) called the Sanctuary Advisory Council, which was established in 2005 by the U.S. Office of National Marine Sanctuaries. This council represents a disparate collection of stakeholders from the oil and gas industry, the diving community, recreational and commercial fishers, conservation groups, educators, and academic researchers. In 2007 the council created a boundary expansion working group to explore whether it should recommend increasing the size of the sanctuary. One member was also the head of the council —a tall, bespectacled Houstonian named Clint Moore. 

Moore wasn’t the first person you’d have in mind to steer a group charged with expanding environmental protections in an area rich in petroleum. As an oil and gas geologist at Diamond Shamrock, he became one of the first to drill in offshore salt layers. Later, with partners from Anadarko Petroleum, he cofounded the exploration company GulfSlope Energy, which continued to discover fossil fuels offshore. A lifelong conservative, Moore served as a Texas delegate to the Republican National Convention in every election from 1996 to 2016. But Moore had a life-changing experience at Flower Garden Banks. During a diving trip about thirty years ago, he had just returned to the charter boat when a manta ray approached him. It behaved, he later said, like a dog looking for attention. Moore grabbed snorkeling gear and jumped back in the water, then reached out and stroked the wings of this docile relative of the sharks. Afterward, he traveled the world to dive and swim with mantas, participating in conservation and protection efforts in Mexico, the Maldives, and Micronesia. With at least two species of manta in the Gulf of Mexico and the coral reefs a critical habitat for juveniles, Moore was committed to ensuring the safety of Flower Garden Banks.

Keith Fern, writer Juli Berwald, and Ben Fern underwater at Stetson Bank on June 15, 2021.
Keith Fern, writer Juli Berwald, and Ben Fern underwater at Stetson Bank on June 15, 2021.Photograph by Ben Lowy

In 2016 the expansion group discussed five options given by the National Oceanic and Atmospheric Administration, which ranged from keeping boundaries status quo to increasing the protected area about seventeen-fold to encompass sites scattered throughout the Gulf all the way to the Florida border with Alabama. The latter was considered a stretch, but it would have allowed the sanctuary to monitor the recovery of important sites affected by BP’s 2010 Deepwater Horizon oil spill. Officials with Flower Garden Banks National Marine Sanctuary supported a middle option: an increase to 383 square miles, which would have expanded the protections around the East and West Flower Garden Banks as well as Stetson Bank and added protections for key ecosystems on fifteen additional banks. Between 2016 and 2018, the boundary expansion working group met at least twenty times, sitting together in a room at Flower Garden Banks headquarters, in Galveston. They studied the five choices, debating how to balance protections for the ecosystem with the needs of energy, fishing, and recreational diving interests. 

The council finally came to an agreement in 2018, and last year the National Oceanic and Atmospheric Administration announced that it was officially asking Congress to approve a plan that would triple the size of Flower Garden Banks to about 160 square miles. Although the enlargement was not as big as the sanctuary staff had hoped for, fourteen new areas—including Bright Bank, named after the early explorer—would now gain the protections of a national marine sanctuary. 

Ruth Perry, an oceanographer who works for Shell, represents oil and gas interests on the Sanctuary Advisory Council. She pointed out to me that the expansion process persisted through Democratic and Republican administrations—those of Barack Obama and Donald Trump—then went into effect under Joe Biden on March 22. “These processes span election cycles, and there’s all kinds of reasons they fail,” she said. “But to get it through in a bipartisan manner—everybody compromising and reaching consensus—it’s really incredible.” 

Not everyone felt as comfortable with the outcome. Sanctuary Advisory Council member Joanie Steinhaus, the Gulf program director of Turtle Island Restoration Network, a conservation group, felt that oil and gas members strong-armed the council into narrowing the expansion in a way that excluded some biologically important areas. The new boundaries encompassed only half the area that sanctuary staff had recommended. “I’m happy that an expansion happened, but I am disappointed in the process, that it wasn’t based on science,” she said. “When you have this opportunity and you don’t go for as much as possible, it’s disappointing.” 

Steve Gittings, the first manager of Flower Garden Banks, who now works in the NOAA Office of National Marine Sanctuaries, in Washington, D.C., reflected on the compromise. “There was a lot of lively debate back and forth, push and pull. All that happened in a pretty productive way, I think. The sanctuary’s ultimate boundaries are pretty limited to the banks themselves and not a lot of buffer areas around the banks, which doesn’t make some people happy and makes other people plenty happy.” He added, “Would I have liked to see bigger buffers, as a conservationist? No question about it. But I came away pretty happy with the boundaries of the sanctuary.” 

Symmetrical brain coral.

Symmetrical brain coral in the West Flower Garden Bank.

Photograph by Ben Lowy

A diver exploring oil platform High Island 376A.

A diver exploring oil platform High Island 376A.

Photograph by Ben Lowy

After two morning dives at West Flower Garden Bank, the captain moved the Fling to an oil platform, High Island 376A, inoperative for now after being battered by several hurricanes during the 2020 season. A repetitive foghorn blast cautioned visitors that it was unstaffed. During our briefing, a dive master warned we were situated in 325 feet of water. “So watch your depth carefully.” Another leap and a few kicks later, I entered the rig structure, which was alive with squadrons of fish. Menacing-looking barracuda and badass crevalle jacks (a large, predatory fish) grabbed my attention first. I saw swirling schools of striped chubs. Closer in, I watched smoky-colored damselfish defending their gardens of coralline algae on the curved surfaces of the oil rig’s crossbeams. Although the platform offered more refuge than the open ocean, without the crevices and tunnels of a reef a fish here is always exposed, always on alert. 

At once, a pack of half a dozen torpedo-shaped forms cruised past with the unmistakable swagger of big sharks. These were blacktips, each about five or six feet long. Most sharks are smart and know what they like to eat, which isn’t neoprene-clad divers. But I was still surprised that I didn’t feel alarmed by their presence. For their part, the sharks seemed nonchalant about our trespass, although the pack continued to circle the platform as long as we remained.

Looking closer through its support beams, I saw many sharp things (the shearing shells of mussels and barnacles), stinging things (fern hydroids and bristly fireworms), invasive things (cup corals the color of orange parking cones, likely trafficked from the Pacific by ships’ hulls or ballast water). I found myself eighty feet deep without realizing it. As I kicked back up through the beams, I considered the rig for the bustling ecosystem that it is, a community that has—in the eight decades since oil was first pumped from offshore—made a lasting place for itself off the Gulf. But it is a very different ecosystem than Flower Garden Banks. Unlike the coral reef, which had filled me with unencumbered joy, the platform made me feel at once awestruck and anxious. 

According to a recent study, coral is the most threatened category of animal in the world—above birds, mammals, and reptiles. And out of the seven seas, the North Atlantic, of which the Gulf of Mexico is considered a part, is among the most stressed by overexploitation. That places Flower Garden Banks coral in what should be a precarious situation. And yet the coral in West Flower Garden Bank is even healthier than in the seventies, increasing from covering about 50 percent of the seafloor to 60 percent in 2019. Meanwhile, in the Florida Keys, the area of seafloor covered by stony coral has decreased to just 2 percent. That discrepancy can make us grateful that Flower Garden Banks is thriving, but it also reminds us that the threats to it, and to all other coral environments, are rising.

Chief among those threats is one aimed at the solar-powered partnership between coral and algae. For reasons that are still the focus of intense research, when temperatures rise, the algal-coral partnership dissolves. This process is called bleaching. Without the pigmented algae, you can see through the clear coral tissue to its bone-white skeleton. It isn’t necessarily permanent. If the water cools, the coral-algae relationship can be reestablished. But if the heat persists, the coral, deprived of its major energy source, starves to death.

Symmetrical brain coral bedecked with a Christmas tree worm.
Symmetrical brain coral bedecked with a Christmas tree worm.Photograph by Ben Lowy

Scientists predict that if nothing is done to curb climate change, the world’s reefs will be in critical condition just a generation from now. As coral reefs are home to a quarter of all marine species, their decline threatens the livelihoods and food sources of millions of people. And because reefs are living barriers that disperse as much as 97 percent of the energy of ocean waves, their demise increases the vulnerability of coastlines to ever-more-intense storms. 

Flower Garden Banks, situated on the northern range of latitudes that can support reef-building coral, may have more time than places closer to the equator. Being bathed in cooler water that wells up from the depths that surround its salt domes might help as well. The first temperature-related mass bleaching here occurred in 2005. So far, it’s remained sporadic. This could make Flower Garden Banks an ecological refuge in a hotter future.

Sarah Davies, a coral geneticist at Boston University, found that one of the dominant species at Flower Garden Banks, the mountainous star coral, had some of the highest genetic diversity of any population studied. Her research also showed that coral larvae, hitching a ride on the Loop Current from Flower Garden Banks, could help reseed damaged reefs in Florida and Cuba. The Gulf’s banks could be a genetic repository as coral populations in other places continue to decline. 

Rising temperatures aren’t the only threat. In recent decades, a palette of diseases has swept through Caribbean coral populations—white plague, black band, yellow blotch—causing significant damage to the reefs there. At Flower Garden Banks, few coral show symptoms of these illnesses. Their unusual distance from land may offer protections from disease-causing sewage runoff and sedimentation. But it’s possible that might not be enough. In 2016 a swath of coral on East Flower Garden Bank died when it was smothered by low-oxygen water that could possibly have had its origin in heavy spring rainfall. As stronger storms become more frequent, even coral on distant salt domes might not be safe from land-borne threats. 

What’s more, a beast of a threat lurks nearby. In 2014 a new coral disease struck near Miami. Affected colonies’ tissues melted away in sheets. Unlike most diseases, which infect just a few species, this one attacked about twenty: mainly boulder and star corals. These same species, many of them centuries old, live in Flower Garden Banks. The pathogen is still unknown, though the disease has a name, stony coral tissue loss disease, or SCTLD, usually pronounced as the deceptively whimsical “skittle-dee.” By 2020, it had spread from the Miami area to the tip of the Florida Keys. It jumped off the reefs there and infected coral throughout the Caribbean, including the eastern coast of the Yucatán. Sanctuary officials worry that anything from the Gulf Loop Current to a diver returning from a trip to an infected reef could transmit the disease to Flower Garden Banks. That might be catastrophic.   

Before my dive trip, I drove to Galveston to visit the Moody Gardens aquarium and meet with Jake Emmert, the aquarium’s dive safety officer and vice chair of the Sanctuary Advisory Council. I followed him to a room that looked like a hospital bay, with a biohazard notice posted on the door. Inside were several shallow tanks lined up like hospital beds. Resting on plastic supports were coral rescued from Florida ahead of the onslaught of SCTLD. They were part of an effort by aquariums and zoos across the country to save the genetic diversity that was disappearing. It was a veritable Noah’s Ark for coral.

When asked whether they were planning to rescue coral from Flower Garden Banks if SCTLD arrived, Emmert nodded somberly. “We’re already talking about it.” 

A recreational fishing boat in the Gulf of Mexico.
A recreational fishing boat in the Gulf of Mexico.Photograph by Ben Lowy

After leaving the oil platform, the Fling motored to East Flower Garden Bank and hitched up to a mooring there. Splashing in for the fourth time in one day, I descended seventy feet, where I encountered not a vast plain like the one in West Flower Garden Bank but something more like hill country. Sheets of coral covered car-size mounds and cascaded down the sides. The coral ruffled around the bases like colorful, layered petticoats. Peeking below one hill, I saw a spiny sea urchin, its long black points quivering like scores of radio antennae. These creatures are important because they garden the reef by grazing away the weedy algae that can overgrow coral. In the eighties, the Caribbean and Flower Garden Banks were struck by a pathogen that almost wiped out long-spined sea urchin populations. They still haven’t recovered in the Caribbean, and coral struggle to regain turf there. At Flower Garden Banks, sea urchins have been making a slow recovery. 

Nestled in another nook was a lionfish, regal but problematic. Native to the Indo-Pacific region, lionfish were introduced into Florida in the mid-eighties. Sporting eighteen venomous spines splayed along their back and fins, and without natural predators, lionfish invaded the Atlantic, the Caribbean, and the Gulf. The first one was seen in Flower Garden Banks in 2011. Just a few years later, the species’ population there had burgeoned into the thousands. Lionfish are voracious, said Steve Gittings, who studied the population explosion. “They eat about one hundred and seventy different kinds of fish, anything that’s about half its body size.” What’s more, lionfish reproduce year-round. A one-year-old female releases 30,000 to 50,000 eggs every three days. To curb lionfish populations, Flower Garden Banks makes an exception to the spearfishing prohibition, holding invitationals targeting the fish. (Once you get past the spines, they make for a great fish taco.) But whether these efforts will bring balance to the system remains in question. Many lionfish remain deeper than spearfishers can go.

After a pasta dinner, I geared up for a fifth dive. This one would again be in East Flower Garden Bank, but at night. During our briefing, the dive masters told us they’d placed strobe lights along the ropes to mark our path. We all clipped small beacon lights onto our tanks and brought extra flashlights in case one flooded. Diving in the inky-dark water wasn’t scary. It was magical. After sunset, coral polyps extend their tentacles to catch the tiny drifting plants and animals known together as plankton. Though they get most of their energy from the sun, coral supplement their diet with nocturnal meals. And when it’s dinnertime, the entire reef transforms from rocklike to soft and wiggly. 

Three sea urchins posed like supermodels in the bright lights of a diver’s camera. Suddenly, their quills were surrounded in thick haze, as if at a Sixth Street dance club in Austin.

As our lights cut through the dark water, we caught other reef denizens in our beams: hermit crabs listing in their shells, snails gliding on slimy tracks, and scallops snapping closed. Deep inside caves, the parrotfish were motionless, having spun themselves in a blanket of protective mucus for the night. 

On the top of one promontory, a group of three sea urchins posed like supermodels in the bright lights of a diver’s camera. Suddenly, their quills were surrounded in thick haze, as if at a Sixth Street dance club in Austin. I squealed through my regulator. The urchins were spawning, releasing their eggs and sperm in synchrony. Many of the fertilized eggs would become larvae that look unaccountably like crystalline spaceships. Most of these larvae would fall prey to the many extended tentacles and mouths on the reef. A relative few would float through the water for a month or more, perhaps finding a home here in Flower Garden Banks, perhaps riding the Gulf Loop Current to Florida or the Caribbean, where urchins are desperately needed. Back on board, I gushed over the urchins, making sure that the photographer had been able to get a shot. He laughed at me. “You’re so excited about sea urchin spooge.” 

Point taken. But also, what we’d seen was promise for a future reef. 

Later I reported what I’d seen via email to Hickerson. “Well this is cool,” she wrote. “Your observation aligns, to the day (in relation to lunar cycle), with a previous [urchin] spawning observation.” Coral aren’t the only ones keeping romantic calendars by the light of the moon. 

A pair of dolphins at Flower Garden Banks.

A pair of dolphins at Flower Garden Banks.

Photograph by Ben Lowy

Three spiny sea urchins spawning.

Three spiny sea urchins spawning.

Photograph by Ben Lowy

As the trip went on, the divers on the boat began to share more conversations. An emergency room nurse from Oklahoma took beautiful underwater photos of the smallest things, including an incredible shot of a conch snail’s eye. Her husband was a firefighter. A tall, lanky diver designed parts for race cars. A software-industry recruiter had recently moved from London to Austin. Several were military veterans, including an ex-Marine who wore a wet suit that looked like a tuxedo. 

In various groups, we sat in the galley’s booths and recounted other dives we’d taken. Stories were told of submerging in Texas lakes, in the marine canyons off Cozumel, and at prized locations in the Caribbean and Pacific. Conversations centered on gear and gauges, cameras and computers. Email addresses were swapped. I asked Daniella Fontana, one of the cooks, who has been with the Fling for twenty years, if this kind of connection occurred on other dive trips. “It happens,” she replied, “every time.” 

On the second night, we motored 46 miles to Stetson Bank, where we arrived in time for a 7 a.m. dive. The sun rose over a glassy blue sea. Diving conditions looked even better than the day before. The siltstone and claystone at Stetson Bank are a lot more fragile than the limestone reefs at East and West Flower Garden Banks. Although the ocean has become more acidic as a consequence of added carbon dioxide in our atmosphere, changes in the pH at Flower Garden Banks haven’t yet become an issue. The erosion we would see below was the natural result of shifting currents. “It’s full of hiding places,” a dive master said. “The best thing to do is find a place and sit and watch. The animals will reveal themselves.”

Heading down the dive rope in the gathering light of the early morning, I saw a form that looked oddly like the recently released Pentagon videos of unidentified aerial phenomena, except the size of half my fingernail and glowing neon blue. I blinked, and it disappeared. But farther down I saw another. And another. One floated toward me, and I cupped it in my hand. It disappeared. But not before I figured out what it was. 

Ostracods, known as seed shrimp because they grow a seed-like shell, are bioluminescent. Like fireflies, ostracods send light signals to their mates and to fend off predators. Hickerson told me that one of her favorite activities on dark summer nights was to flash her light through the water and watch the twinkle. “You’re talking to ostracods,” she’d said. In the dim morning light, these ostracods were still quite chatty.

Reaching the rocky reef, I narrowed my focus. Bossy blennies, propped on their front fins atop the limestone, stared back at me with big, dark eyes. I was captivated for quite a while by a trunkfish, a pyramid-shaped critter that bobbles as it swims. It scooped up a pile of sand to sieve for tiny worms before blasting the remains back on the reef. A group of tinier fish rushed toward the dustup, hunting for scraps. The spray caused me to pause and listen. This was a noisy place, full of crunching and chomping, snapping and scrubbing, the sounds of vibrant life. 

I followed my dive partner to look into a cave, where we discovered a black-and-yellow moray eel, sharp-toothed and gaping at the camera. As I turned to explore, a stingray at least four feet across glided into my peripheral vision. None of the other divers with cameras nearby noticed her. I kept her to myself for a few moments. Then I whistle-hummed through my regulator to catch their attention so they could capture her grace on film, bringing it to the surface with us. 

In the weeks after my journey into Flower Garden Banks, I didn’t much regret that I hadn’t seen a manta ray. I wasn’t surprised not to see a whale shark, which are more common later in summer. The image that kept returning to me wasn’t the gentle ray, the glowing ostracods, or even the spawning urchins. It was the margins marking the turf battles between the massive colonies of coral, and how they’d signaled a healthy, growing reef. 

Clint Moore passed away in 2019, at the age of 63. Scott Hickman, who represents the commercial fishing industry on the Sanctuary Advisory Council, became its chair and saw the expansion process to completion. After my diving trip, I reached out to Hickman. A hunting and fishing guide for thirty years, he spoke to me by phone as he drove around a ranch he manages in Brazoria County, just west of Galveston. We talked about fishing, oil platforms, biodiversity, and pollution. The conversation turned to the value of compromise—so unfashionable these days, and so essential to the expansion of the Flower Garden Banks sanctuary.

We also talked about Moore’s legacy and his key role in the sanctuary’s enhancement. “He loved Flower Garden Banks,” Hickman told me. “He was a brilliant geologist and a hard-core conservative. We didn’t always agree on political things, and that’s okay because we are American and we can disagree. But the sanctuary—that we could agree on.”

Austin-based science writer Juli Berwald is the author of Spineless: The Science of Jellyfish and the Art of Growing a Backbone. Her next book, Life on the Rocks: Building a Future for Coral Reefs, will be published by Riverhead books in April 2022.

This article originally appeared in the September 2021 issue of Texas Monthly with the headline “The Gulf’s Secret Garden.” Subscribe today.