The Last Coral Reefs

There’s only one way to lower a $20,000 custom-made underwater camera from a swaying fishing boat into the open sea: very, very carefully. And that’s exactly how Manuel Gonzalez-Rivero’s colleagues handled the SVII camera as they nudged it overboard, where the coral ecologist was bobbing in the bathtub-warm waters off the Central American country of Belize. Gonzalez-Rivero is based at the University of Queensland’s Global Change Institute in Australia, but he was in the Caribbean working with the Catlin Seaview Survey, a scientific expedition that is assessing threatened coral reefs around the world. Once in the water, the cumbersome SVII–a beach-ball-size camera head with three separate lenses at the end of a 7-ft. (2 m) pole–was easy for Gonzalez-Rivero to maneuver. The camera’s attached propeller sled saved the scientist the work of swimming as he covered more than a mile of Belize’s protected Glover’s Reef, part of the vast and endangered Mesoamerican Reef that stretches from southern Honduras to the eastern tip of Mexico.

Every three seconds, the lenses on the SVII–facing to the left, right and below the camera head–snapped pictures of the reef. Over the course of his 45-minute dive, Gonzalez-Rivero produced more than 900 detailed images of Glover’s Reef, each one rich with data about corals and sea life. Back on the catamaran that served as the expedition’s temporary base, those images would be processed to generate a precise three-dimensional image of the reef. Later, computers at the Scripps Institution of Oceanography would analyze the pictures, giving scientists a quick diagnosis of the health of one of the most valuable marine ecosystems in the Caribbean. What’s long been possible on land, thanks to satellites scanning jungles and deserts, is now feasible beneath the waves. “Every coral reef is different,” says Gonzalez-Rivero. “This will allow us to see the reef as it really is.”

And we have to see it today, because coral reefs may not be here tomorrow. It’s a cliché to call coral reefs the rain forests of the ocean, but if anything, that understates their ecological value. They occupy less than 0.1% of the sea area, yet “between one-fourth and one-third of everything that lives in the ocean lives in a coral reef,” says Nancy Knowlton, who holds the Smithsonian Institution’s Sant Chair in Marine Science. Coral reefs support more species per square kilometer than any other marine environment, providing habitat, food and spawning grounds. And fish are not the only beneficiaries. The net economic value of coral reefs globally is almost $30 billion a year, and some 500 million people around the world depend on coral reefs for food, coastal protection and tourism.

At a time when climate concerns continue to mount–a widely watched March 31 report from a United Nations panel warned of drastic effects across the globe–coral reefs are under intense threat. Overfishing and coastal overpollution and development have left all but the most remote reefs a shadow of what they once were. By one estimate, the Caribbean has lost 80% of its coral cover over the past 50 years. And the future is even darker: the one-two punch of global warming and ocean acidification could make the seas essentially inhospitable to coral, with dire consequences for marine life. The U.N. report, from the Intergovernmental Panel on Climate Change (IPCC), warned that coral reefs are “the most vulnerable marine ecosystem on Earth” to the effects of global warming. “If we don’t dodge this bullet, the only coral reefs that our children’s grandchildren will see will be in picture books,” says Steve Palumbi, director of Stanford University’s Hopkins Marine Station.

That’s what makes the Catlin Seaview Survey so timely. The oceans in their full volume account for as much as 90% of the planet, but humans have seen just 5% of the underwater world with their own eyes. Ocean exploration can be expensive, difficult and time-consuming, even in the relatively shallow coastal waters where most reefs are found. But Seaview, which aims to survey every major coral reef worldwide, is able to take advantage of new advances in video and computer analysis to produce a long, sustained look at the oceans, essentially digitizing the seas. The result will be the kind of data that marine scientists have long craved. “By creating a really large global baseline of coral health, we can identify the areas that really need protecting,” says Richard Vevers, project director of the Catlin Seaview Survey. “We want to reveal the oceans of the world.”

Disappearing Riches

While I was in Belize with the Seaview team, I had the chance to view a coral reef the old-fashioned way–I dived it. Glover’s Reef, which is about 28 miles (45 km) off the Belize coast, lies at the heart of the largest reef system in the western hemisphere. As I hovered lazily near the ocean floor–while Gonzalez-Rivero and his colleagues carried out actual science above me–I could pick out boulder-size brain coral, jagged fire coral and majestic elkhorn coral. Sea fans billowed like flags in the underwater current.

Reefs look like living rocks–and in a sense, that’s what they are. Corals are tiny invertebrates that exist in symbiosis with photosynthetic single-cell algae called zooxanthellae, which live inside the coral’s tissue. (The zooxanthellae provide food to the coral by converting sunlight into energy.) Corals build up hard exoskeletons made of layers of secreted calcium carbonate, which form the reef. In a healthy reef, you can see everything from tiny gobies to predatory sharks swimming amid a network of coral as intricate as a medieval cathedral. “Coral reefs are a magic ecosystem,” says Palumbi. “If you could make the deserts bloom on land, that’s what coral reefs do for the oceans.”

Glover’s Reef, which is part of Belize’s protected Hol Chan Marine Reserve, is one of the healthier coral ecosystems in the Caribbean. But even here the reef isn’t what it once was. Coral cover dropped from 80% in 1971 to 13% in 1999, although there has been some recovery since, thanks to the recent establishment of a no-fishing zone. Most other Caribbean reefs are in far worse shape. The heavily developed waters off the coasts of countries like Jamaica are now little more than coral graveyards. Veteran coral ecologists who began by diving in the once verdant reefs of the Caribbean have witnessed the coral collapse over the course of their careers. “I’m 64, and everyone of my generation who became a conservation biologist has seen this loss happen in real time,” says Knowlton.

While Caribbean reefs have been particularly hard hit, corals around the world face the same threats. Overfishing species at the top of the food chain can cause a chain reaction, leading to the loss of smaller herbivores that play an important role in controlling the growth of seaweed, which competes with corals for living space. Pollution from coastal areas can kill corals–especially fertilizer runoff from agriculture, which can promote the growth of algae species that crowd out corals. Humans can accidentally introduce invasive species like the lionfish, a voracious eater that has plundered the Caribbean like Blackbeard the pirate. At least a quarter of the world’s corals have been lost over the past 25 years.

What really frightens coral scientists are the threats that will arise in the future. “If we push this too far, corals won’t be able to bounce back,” says Peter Mumby, a coral ecologist at the University of Queensland. “The whole system will collapse over time.” Climate change poses an existential challenge. Corals don’t like it when the water around them suddenly heats up, which can trigger what’s known as bleaching. The coral organism reacts by ejecting the zooxanthella algae living inside its tissues, which robs the coral of both its color and its source of food. While bleaching doesn’t necessarily kill the coral outright, it leaves it extremely vulnerable to other stresses. (In 1998, El Niño–led warming sparked the worst bleaching event on record, with 16% of the world’s coral lost in a year.) Even as climate change warms the seas, the additional carbon dioxide absorbed by the oceans will turn the water more acidic, which will in turn interfere with corals’ ability to form reefs. A 2013 study by researchers at the Carnegie Institution projected that if carbon emissions are not brought under control, no part of the ocean will be able to support coral reefs by 2100, and the new IPCC report predicts that Australia’s Great Barrier Reef will continue to degrade even if warming is slower than projected. “You could lose the coral reefs altogether,” says Ken Caldeira, an atmospheric scientist at Carnegie and a co-author of the paper. Coral scientists are right to fear that they could spend the rest of their careers watching their subject die.

Recording for Posterity

When Richard Vevers switched careers from advertising to underwater photography, he became friends with the great Australian underwater filmmaker and shark expert Ron Taylor, best known for his work on movies like Jaws. Vevers would dive along the Great Barrier Reef and bring back what he thought were images of a pristine marine ecosystem, bristling with coral and sea life. But when he showed his pictures to Taylor, the veteran photographer would just shake his head. “He’d say, ‘That’s great, but you don’t know how it used to be,'” says Vevers. “I didn’t believe it at first, but it began to sink in. I realized that there’s this decline that’s been happening almost too slow for people to notice.”

There’s a term for that decline: shifting baselines. Fisheries scientist Daniel Pauly coined it to describe how overfishing has changed the oceans so rapidly over the past several decades that what we think of as normal from recent experience–the baseline–has had to shift to keep up with what is actually a diminished reality. “We transform the world, but we don’t remember it,” Pauly said in a 2010 TED talk. “We adjust our baseline to the new level, and we don’t recall what was there.”

Shifting baselines can be seen in all environmental science, but they’re a particular problem in ocean research. Marine scientists have had to rely on quick hits–grabbing data from scuba surveys, competing for a spot on a submersible. Even those research trips are growing rarer in a budget-constrained age. Don Walsh and Jacques Piccard reached the bottom of the Mariana Trench, the deepest point on the planet, in 1960, but no one returned there until director James Cameron did so in 2012 in a submersible he designed and paid for himself. Our understanding of the oceans is “very data-poor,” says David Kline of the Scripps Institution of Oceanography. It’s as if we were trying to comprehend a movie by seeing a few random frames rather than the full, uncut length.

The Catlin Seaview Survey is working to create that complete film. The photographs taken by the SVII camera can be digitally combined to create panoramic images that reveal the underwater world with striking depth and clarity. Seaview has partnered with Google to put many of those images online as part of Google Ocean’s efforts to take its Street View program–which shows ground-level photographs from around the world–beneath the waves. (Seaview is primarily sponsored by the Bermuda-based reinsurance company Catlin Group, which has been funding climate-change research, knowing that global warming could hit the insurance industry hard.) Underwater images from Seaview’s first extended expedition–a four-month mission in 2013 that covered more than 90 miles (145 km) of the Great Barrier Reef–have already been viewed millions of times. With the help of time-lapse technology, the images can be stitched together to engineer what seems like a digital scuba dive through one of the best-preserved coral-reef systems in the world–albeit one that has lost more than 50% of its coral cover over the past 30 years. “People can see the beauty of this world for themselves,” says Jenifer Austin Foulkes, project manager of the Google Ocean Program. “It’s a powerful tool.”

The underwater world has suffered as an environmental cause because of its inaccessibility. Scuba diving, after all, became possible only in the postwar era. Vevers hopes the beauty and accessibility of the images that Seaview records will help motivate the public to care for the seas. “Ninety-nine percent of people don’t dive and probably never will,” he says. “We need to bring the oceans to the people.” If people can dial up a view of their closest reef the way they can zero in on their childhood home on Google Earth, they might begin to care about the 70% of the planet that is covered in water.

But the lasting value of Seaview will be in the science it supports. Underwater research has always been limited by two things: air and space. Humans–in scuba gear or in submersibles–can stay underwater for only so long and can bring only so much equipment with them. The standard method of surveying coral involved researchers diving a reef and taking photographs of the area they covered, square foot by square foot, then analyzing those images on a research boat or at a station. Each of those images could require 15 to 30 minutes of work by a trained observer. Scientists had to extrapolate the whole from a small data set, not least because there was no way to survey an entire coral reef. The Great Barrier Reef, for example, covers 134,364 sq. mi. (348,000 sq km).

A Gloomy Picture

Over the next several years, Seaview expects to cover the Caribbean, the Coral Sea in Southeast Asia, the Indian Ocean, the Mediterranean and the Middle East, producing hundreds of thousands of underwater images along the way. Under the old methods, it would have taken years for scientists to analyze it all, and most of the pictures would likely have remained in a dusty hard drive somewhere in the back of a lab. But Scripps and the University of California at San Diego, employing facial-recognition technology similar to what the CIA employs to analyze crowd photos, are using a computer program to scan each image from the expedition and spit out the pictured species and extent of coral growth–all more than a hundred times faster than such work could have been done by humans alone. The accuracy of the machine is already at 90%, and as the program analyzes more images, it will become more precise, learning along the way. “What used to take us years we can now do in weeks and months,” says Scripps’ Kline. “We’ll have large-scale, quality data about the health of the reefs, and that will let managers make much more informed decisions about protection policies.” This is a Big Data solution to a very big scientific challenge.

There’s no time to waste: the picture is vanishing even as we take it. I loved diving in the aquamarine waters of Glover’s Reef, letting my fingers drift past the outstretched arms of elkhorn coral. It was one of the most beautiful places I’d ever been. Yet I could tell–or maybe just feel–that something had been lost. It seemed empty of all but the smallest species, the result of years of intense fishing that more recent protections have only begun to reverse. My guide saw a hammerhead shark circling in the blue, but I missed it. It’s easy to miss things underwater.