The Forgotten Deep
The Gulf’s little-seen deep-water ecosystems may bear the brunt of the BP oil spill’s damage.
By Wendee Holtcamp
In late July, Tropical Storm Bonnie swept across the Gulf of Mexico, sending Coast Guard and BP workers scrambling to temporarily shut down their oil spill cleanup operations. Just days before, on July 15, BP had capped the largest accidental oil spill in the history of the petroleum industry, 50 miles off the Louisiana coast. The spill was caused when the Deepwater Horizon rig leased by BP tragically exploded on April 20 and sank two days later, on Earth Day.
The Gulf provides energy to fuel our cars and light our homes and is a hotbed for recreation — beach-going, surfing, fishing, birding — not to mention commercial fishing and shrimping. Yet it is maligned and misunderstood as much as it is beloved.
“This place has a way of wrapping itself around your heart,” said famed oceanographer Sylvia Earle at a panel held by the Harte Research Institute for Gulf of Mexico Studies in late June. “It’s our backyard, and the magnitude of ignorance about what is actually there is now beginning to dawn on us as we struggle to weigh impacts of this catastrophe.”
Writer Melissa Gaskill and I hit the road to investigate the spill, driving from Texas to Alabama and back, stopping to talk with biologists along the way. We visited several beaches, where we saw fresh oil and tar balls. Yet, far more oil remained in the vast Gulf, creating untold effects on the sea creatures beyond our sight. As we headed back home, I got a call: Did we want to fly over the well site? I was excited at the chance to see the oil’s effects, writ large over the Gulf.
We hightailed it to New Orleans, boarded a Coast Guard plane with a dozen reporters, buckled up and rose above the tarmac, flying south over Louisiana’s verdant latticework of wetlands — crucial nursery grounds for finfish and shellfish — and then over the open ocean. I peered out the small windows, watching for orange floating oil, a sheen, something.
When we reached Mississippi Canyon Block 252 — the site where the Deepwater Horizon oil rig leased by BP once stood — they opened the back of the plane, and below us, several large ships stood eerily still, like sentinels. I felt exhilarated as the plane swooped around the site, but kept wondering: Where was all the oil? I saw only cloud shadows. Was this spill of 206 million gallons an inconsequential drop in the bucket, or a catastrophe? Could the millions of gallons of oil plus the 1.84 million gallons of chemical dispersant be merely two more pollutants in an already tainted Gulf?
And therein lies the catch. The Gulf, particularly in the region of the spill, is anything but a lifeless salty lagoon filled with pollutants from the Mississippi River. “Many people think of this area as part of the well-publicized ‘dead zone’ — a barren expanse of mud substrate, dotted with oil rigs and occasionally punctuated with a rocky outcrop,” writes George Schmahl, chief scientist on a 2003 National Oceanic and Atmospheric Administration Gulf expedition, in his trip report on the northern Gulf — very near the site of the BP spill. “In fact, the northern Gulf of Mexico has thriving coral reefs, rocky hard bottom teeming with life, chemosynthetic vent communities, deep-water coral assemblages, incredible fish resources, an endemic whale population and much more. The diversity of life in the Gulf is nothing less than incredible.”
Despite pleas by scientists, many of which have taken place beyond the public eye, the potential damage from the oil to these deep-water corals and planktonic creatures that quite literally feed and fuel the entire food web has received scant media attention. Since most folks experience oceans from trips to the beach, we can perhaps be forgiven for focusing our concern on coastal species and habitats — oiled pelicans, nesting sea turtles, recreational and commercial fish, spoiled marshes. But many marine scientists theorize that the oil’s most damaging legacy could be the harm to these deep-ocean species that remain “out of sight, out of mind.”
“America’s Mediterranean,” with its 4,000 miles of coastline and 615,000 square miles of ocean, is a Shangri-La of marine biodiversity. The Gulf of Mexico is rimmed by a shallow continental shelf with undersea pinnacles, buttes, canyons and mesas. A 75-mile-long gash in the continental shelf called the Mississippi Canyon lies just southwest of the oil spill site. The real gems of the Gulf are a series of pinnacles emerging from the Gulf floor, providing hard structures on which deep-water corals attach. Some are called hard banks. These dynamic reefs form a “string of pearls” encircling the Gulf of Mexico, including the South Texas Banks, the Mississippi and Alabama Pinnacles, Pulley Ridge (off Florida) and some spots off Cuba and Mexico. Viosca Knoll lies just north of the spill site.
“Deep-water corals and hard-bottom communities throughout the Gulf of Mexico have been studied as isolated environments,” says Suzanne Fredericq, a University of Louisiana–Lafayette biology professor. “But scientists have made discoveries that helped link these communities. I think it’s a marvelous idea not to look at such hard banks in isolation, but instead to understand their geology and biodiversity in the overall context of historical biogeography.” It’s thought that marine organisms may migrate between these “islands” along the Gulf Stream — and hence that they’re interconnected. If Viosca Knoll is devastated — and Harte institute biologists plan to revisit the once-thriving reef soon — it could affect marine life throughout the Gulf.
Some pinnacles are salt domes that uplift through the ocean floor, while others are “drowned reefs” — fossil remains of calcium carbonate reef-building corals that thrived in the late Pleistocene Era 12,000 years ago when the Gulf was shallower, but that died when sea levels rose. Today, gorgonian sea fans, sea pens, red octocorals, black corals and bamboo corals can attach to the pinnacles’ hard surfaces, forming rainbows of marine life with pinks, purples, oranges, reds and whites.
Since the formations lie far too deep for human divers, scientists use remotely operated vehicles, or ROVs, with collecting arms and video cameras to study the marine organisms. Around these reefs, scientists have found solitary cup corals, sponges, brittle stars, squat lobsters, white sea stars, urchins and more. Interesting interactions have been observed, such as a tiny commensal shrimp living in the spines of a sea urchin, and a Callogorgia coral covered in skate egg cases. A great variety of marine fish also congregate here — red snapper, grouper, jacks, rough-tongued bass, damselfish, sharks and eels — creating hot spots for deep-sea fishing.
Biologists recently divided the Gulf into eight pie pieces; the sector containing the BP spill had the second-highest number of total known species, 8,333, and the highest number of species in this sector were at the 5,000-foot depth at which the BP wellhead sat. And some of them are ancient organisms. Black corals living near the spill site were found to be more than 1,000 years old, says Thomas Shirley, who holds the Harte institute’s endowed chair for biodiversity. “If you kill one of those, that’s like killing a giant sequoia tree.”
Most of the affected organisms die far beyond our sight, merely sinking to the ocean floor or becoming ghosts of the ancient once-vibrant corals. In mid-June, the public got a peek into the potential devastation to the deep ocean when thousands of organisms were found floating, dead, on the ocean surface near the oil spill site. They were initially misidentified as sea cucumbers, which they resemble, but they were actually pyrosomes, free-floating colonies of gelatinous tunicates. These effects cause grave concern to those who study Gulf marine life.
Although fish have a gene (Cytochrome p450) that allows them to metabolize oil — within reasonable quantities — their fertilized eggs and hatching embryos remain highly vulnerable to both oil and dispersants, and some of the oil metabolites can damage fish tissue. Invertebrates, which make up the bulk of undersea creatures — clams, mussels, worms, corals, squid, octopi, crabs, jellyfish and zillions of minute zooplankton — do not metabolize oil. Those that survive contact with oil may accumulate toxins in their body tissue, putting other creatures that eat them at risk.
Oil usually floats on water, but because of the high expulsion rate of hot oil into the cold, deep water — which was at high pressure a mile undersea — some of it emulsified into a fine mist, like a spray can of olive oil. Dispersants used both at the surface and at depth increased this phenomenon. On their own, most dispersants are less toxic than oil, but scientists believe the “dispersed oil” becomes more toxic than either alone.
“With oil dispersion, much goes into the water column as tiny droplets. This increases the surface area of the oil,” explains Peter Hodson, a biology professor at Queens University in Toronto, who has studied the impact of dispersants, oil and dispersed oil on fish. “A much larger volume of water will achieve toxic concentrations for a much longer time, meaning a greater risk of toxicity.”
Dispersion creates drops so small that the oil is completely invisible to the naked eye, ranging from 3 to 80 microns. This overlaps with the preferred size range of food ingested by many filter-feeding animals — sea stars, sea anemones, bivalves and copepods. Tiny oil droplets can also clog fish gills and be absorbed through the delicate skin and membranes of marine organisms.
Most folks don’t think twice about zooplankton, which includes eggs and larvae of larger organisms, like fish, squid and jellyfish, as well as particularly diminutive crustaceans like amphipods and copepods. Zooplankton provide crucial middle links in the food web but are highly vulnerable to oil. Many fish eggs and larvae can die at levels of dispersed oil as low as 1 to 5 parts per million. Levels of 20 to 50 parts per million can be toxic to other marine invertebrates and fish. The loss of mass quantities of zooplankton also means less available food for larger marine organisms that feed on them — long-lived organisms like whale sharks, tuna, tarpon and more.
“I feel pretty concerned that we had a significant impact on everything in the water column this year,” says Larry McKinney, executive director of the Harte institute and former director of the Coastal Fisheries Division of the Texas Parks and Wildlife Department. “It was a massive use of dispersants all through the water column.”
Besides killing animals outright, exposure to oil can cause disease, lowered reproductive success, genetic mutations and deformities, studies have shown. And most of these impacts will take place far beyond our watching eyes, in the forgotten deep.
The National Science Foundation has already funded at least 140 rapid-response grants so scientists can document effects of the oil as quickly as possible. Studies include such topics as mapping the oil plumes, studying how oil may cause genetic mutations in wetland fish and documenting the effects of oil on these deep-water reefs.
In one grant, biologists have documented oil droplets inside blue crab larvae all along the Gulf Coast, from Alabama to Galveston. Blue crabs spawn offshore, and the larvae float in currents until they make their way into coastal estuaries, where biologists are able to collect some for research. Whether or not the oil drops turn out to be BP oil, a byproduct from the crabs metabolizing oil or something else in the water remains to be seen, but Gulf Coast Research Laboratory biologist Harriet Perry — whom we visited in Ocean Springs, Miss. — has not seen anything like it in 40 years studying them.
Only a few weeks after our road trip ended, National Incident Command issued a report saying that of 206 million gallons, 26 percent washed ashore or remains as surface sheen, 24 percent had been dispersed (the infamous “plumes”) and the rest was recovered, skimmed or burned. Many scientists working in the Gulf criticized the report as overly rosy. In reality, no one knows the precise amount of oil that leaked, or how much remains. The true effects of the oil spill in our backyard will be revealed months, years and decades from now, but there’s reason for hope. This disaster, which tragically took 11 people’s lives, could easily end up forgotten — the way most folks forgot about the Ixtoc spill off Mexico’s Gulf Coast in 1979 — or it could create a sea change, propelling us toward a sustainable future.
McKinney would like to see these deep-water pinnacles protected through what’s been dubbed the “Islands in the Stream” conservation plan. The concept got a lot of support by scientists and conservationists but was halted in 2008 because of oil and gas and commercial fisheries interests. McKinney and his Harte institute colleagues believe it’s time to resurrect the project, with all parties considered. Several of the institute’s scientists will be going on research cruises to further study the sites and push for their preservation.
Earle, the oceanographer, also encouraged us to use the spill as a wake-up call for renewable energy sources. “It used to be whale oil and seal oil that gave us light and heat,” she says. “Maybe now we’ll find an alternative method to fossil fuel. Some people say it’s too expensive, but what’s expensive? The loss of the Gulf of Mexico to people who depend on a healthy ocean? We need to think like an ocean — to think what we can give back to the Gulf. Perhaps a network of protected areas would give the ocean a chance to recover.”
Texas’ Forgotten Oil Spill
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Although it now pales in comparison to the massive Gulf oil spill, Texas had its own major spill back in January. An 800-foot tanker, the Eagle Otome, veered off-course inside the Sabine-Neches Waterway near Port Arthur, striking a towboat that impaled the tanker’s hull. Before long, 462,000 gallons of crude oil had poured into the water, Texas’ biggest spill since 1994, when a ruptured pipeline and explosion ignited the lower San Jacinto River. When a spill of this magnitude occurs, an Incident Command System goes into effect, made up of federal and state agencies and the responsible party; this same system occurred during the Gulf spill. “Once we get a report, we get all of our equipment together, we check maps to see where the spill occurred, and get in touch with the Command Center,” explains TPWD Coastal Fisheries biologist and Kills and Spills Team member Steven Mitchell. Then they head to the field. “We were responding to calls for oiled wildlife, surveying to see what impacts were occurring and if there were any sensitive areas affected and scoping out areas for cleanup,” Mitchell says, describing the scene days after the spill. “There was a lot of black oil flowing down the ship channel, and a lot of the VOCs [volatile organic compounds] in the air. You could smell it.” Cleanup folks set out oil containment booms on the water. These booms float on the water to help contain oil within certain areas, while skimmers remove as much as possible. Where oil reaches the coastline, cleanup crews also use super-absorbent square pads on giant sticks to literally mop up the mess. During the next few weeks, all oiled birds found alive were taken to a rehabilitation center run by Rhonda Murgatroyd of Wildlife Response Services. “They don’t automatically go into a wash, but they need to de-stress. We conduct a physical exam, take their temperature and see the degree of oiling. Oftentimes we give them fluids, and they’re put under a heat lamp so they can regain their body heat,” she explains. “The hours are long and at times, when the loss of an animal occurs, emotionally exhausting,” says Murgatroyd. “However, the rewards far outweigh anything else when we witness the rehabilitated animal fly free.” In this spill, they found only seven dead birds, plus 10 oiled live ones, all of which they released. “We somewhat dodged a bullet, but it’s definitely not a no-harm spill,” says Jamie Schubert, TPWD Coastal Fisheries Upper Coast ecosystem biologist. Some booms were not fully effective. “There was some unfortunate oiling of marshes within the Keith Lake area in J.D. Murphree WMA [Wildlife Management Area], along parts of the Gulf Intracoastal Waterway and along Taylor Bayou — one of few remaining healthy stretches of ‘intermediate marsh.’” The news of the spill was dwarfed by the April explosion of the Deepwater Horizon rig, but it’s not unimportant. A spill of 462,000 gallons of crude oil is never without impact. A recent study shows that 20,000 gallons of oil from the Exxon Valdez still remain in Alaska, having seeped deep into sediment, where less oxygen and fewer micro-organisms mean slower biodegradation. With the Port Arthur spill, Mitchell and other TPWD biologists have been concerned about cleanup contractors causing long-term physical damage to the marshes. |
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