For almost three decades I've been studying nudibranchs in the tropical Indian and Pacific Oceans. Nudibranchs are beautiful and brightly colored sea slugs that thrive on healthy coral reefs. While that has been exhilarating, it is the changes that I've seen on these reefs that make me sit upright in bed in the middle of the night. Climate change is seriously endangering these richest reservoirs of marine biodiversity. Here is my story of some of these alarming changes.
My journey began in Cosmoledo (map), a remote atoll in the western Indian Ocean, 200 miles northwest of Madagascar and 600 miles west of the African continent. I first visited there in 1986 as part of a Smithsonian Institution expedition. I remember the reefs were teeming with lush coral growth and there was an amazing display of colorful reef fish. When I went back in 1999, the land looked very much the same, a beautiful white sand beach, palm trees swaying, and Tournefortia and Scaevola bushes embracing the shoreline. What an idyllic setting. It was great to be back, or so I thought. Then I donned my mask, snorkel, and fins to plunge into the warm waters. This time something was very different. The fish were there in abundance but the corals were all dead. There were a few isolated coral heads that had just begun to recover, but 95% of the reef was dead. The fish swam around looking for something to eat and for their old habitat. It reminded me of people returning to find their homes in ruins after a wildfire had roared through a forest. I was shocked at what I saw.
Here we were on one of the most remote atolls in the Indian Ocean, where only the occasional turtle hunter or fisherman ventures. There is no permanent habitation, only a few huts where people sleep when they are fishing or gathering coconuts. There is no pollution, virtually no resident human impact, and no local explanation for this profound decimation of a once-healthy reef.
This is when I had my first "aha" moment about climate change. For me it was real and catastrophic in what had happened to the reefs in the western Indian Ocean. From that day forward, I became convinced that the world's richest oceanic habitats, the coral reefs, are seriously threatened.
However, I didn't see more evidence of coral death in the parts of the Indian and Pacific Oceans where I was spending a couple of months each year studying the diversity of nudibranchs. Meanwhile, my colleagues in the Caribbean continued to report serious problems on their coral reefs. At the International Coral Reef Congress held in Okinawa in 2004, reef biologists reported that the changes in the dominant coral species in the Caribbean had not been replicated in the geologic core samples they made in the reef that went back through 4000 years of history. At this moment, I remember turning to one of my colleagues and saying, "this is incontrovertible evidence that something unprecedented has changed, and nobody can possibly doubt that this represents human-induced climate change."
More trouble in the Indian Ocean
My next visit to a coral reef in trouble came in October 2005. Three of my colleagues and I had travelled from the California Academy of Sciences to the remote Radama Islands (map) off the northwest coast of Madagascar to join a team of Malagasy scientists and staff from the Wildlife Conservation Society (WCS). Our mission was to survey the unique biota of the islands, which had just received official conservation status from the Malagasy government. This was a major accomplishment and one that gave all of us hope that the reefs of Madagascar were beginning to receive the necessary protection they so badly needed. Our colleagues at the WCS were working closely with local community leaders to ease the fishing pressures in these protected areas and find new, more sustainable methods of fishing, and setting aside no-take zones that would function as nurseries to replenish areas where sustainable harvesting could take place. The local residents were embracing this concept.
We were all excited to see how the newly adopted conservation practices were paying off in this biologically rich area. Our first dive in the islands was on a remote pinnacle several miles offshore. The water was teeming with marine life. Our attention was focused on the nudibranchs, soft corals, and barnacles that we individually study. After the first dive we all focused on the new discoveries we had made. My colleague Shireen Fahey and I found two new species of nudibranchs that had never before been seen by scientists. Bob Van Syoc was confident he had found new barnacle species, and Gary Williams had found soft corals that he had never seen previously. We were off to a great start. This was just the ammunition that the WCS needed to reinforce the uniqueness of the area and why it must be protected.
All photographs in the slideshow are by Dr. Terry Gosliner unless otherwise mentioned and obtained with permission from Dr. Terry Gosliner and the California Academy of Sciences. The slide show was curated by Subhankar Banerjee.
Subsequent dives were equally spectacular in the wealth of new species. After the second or third dive, our conversations at the surface between dives began to shift. We were still finding exciting new animals, but we were also noticing that more and more of the coral was being overgrown by a light brownish green slime. In some cases, it was clearly covering, smothering, and killing whole coral colonies. Gary had the insight to collect a small sample to take back to San Francisco for further study. After examination we recognized this was a blue-green bacterium, also known as cyanobacteria, which are abundant in habitats that are severely stressed or have too many nutrients.
This was happening independently of local human activity. The culprit, however, was human activity worlds away in the industrialized nations that contributed to global warming and consequently caused stress to the temperature-sensitive corals. Despite adopting more sustainable fishing practices, the reefs surrounding the Radama islanders were slowly dying from suffocating slime. This realization put a damper on our excitement of the wonderful new species we had discovered and brought the backdrop concern to the forefront as the dominant feeling about the trip. It just did not seem fair that subsistence fisherfolks who were adopting conservation-minded practices were still facing the impacts of their fellow humans in the developed countries half a world away.
Trauma in Thailand
Fast forward to July 18, 2010. I had just landed in Phuket, Thailand (map) to attend the World Congress of Malacology. Researchers who study mollusks gather every three years to exchange latest research findings in this conference. Everyone was excited to see what new discoveries had been made, what new students were coming along, and to meet and reconnect with colleagues to develop new ideas for collaborative projects. I ran into one of my closest colleagues from Spain, Marta Pola. She had spent one and a half years working with me in San Francisco and I had also co-supervised her doctoral research at the University of Madrid. Six months earlier she had returned to Spain to accept a faculty position at the University of Madrid. She was at a reception with many of my other Spanish colleagues that we affectionately call the Spanish Mafia. They were all going to go snorkeling the next morning on some offshore islands and there was room for me to join them.
The reefs of Phuket are renowned for their beauty and I had heard they were recovering nicely from the damage wrought by the deadly Boxing Day tsunami in 2004. Our destination was a little islet appropriately called Coral Island. A twenty-minute boat ride brought us to a sheltered cove with a couple of dozen tourists on the beach. As we approached the shallows I could see scattered patches of white. As we got even closer to the beach, I saw that the white spots were coral heads and they looked like snow-capped peaks rather than the golden browns and greens of healthy coral colonies. The rich colors are caused by the presence of minute algae called zooxanthellae that live symbiotically in the coral tissues. The sugars produced by the zooxanthellae can provide more than half the nutrition of the corals. When corals are stressed, they expel their zooxanthellae and they appear white. This is called coral bleaching and is a sign that something is seriously wrong.
When I put on my mask and slipped into the water, I saw what the white patches were all about. Almost all the corals were dead or severely bleached. I've seen coral bleaching before in the Philippines and a few other places. Its usually a coral head here, a coral head there. While alarming, it is isolated and not commonly encountered. On Coral Island, 90% of the corals were dead or bleached. We were all shocked. None of us had seen anything like this. When we got back to the hotel, I Googled "coral bleaching, Phuket" and found several articles in Thai newpapers describing how the water temperature had gotten up to 91-93 degrees Fahrenheit in early May. By May 10, divers started noticing coral bleaching. Now, two months later, the ultimate nightmare was unfolding.
I ran into my Thai academic sibling, Suchana Chavanich, who had studied at the University of New Hampshire with my Ph.D advisor Larry Harris. She has become one of the experts of coral reefs in Thailand. I asked her about the coral bleaching and she explained to me that almost all of the reefs in Thailand on both sides of the Malay Peninsula were suffering from severe bleaching. Later that afternoon, I was talking to a couple of Malaysian colleagues at the conference and they reported that the same intensity of bleaching had also been observed to the south on Malaysian reefs. In the following weeks reports of bleaching kept coming in from the Maldives, then Aceh in Indonesia, and then Java. It was clear that we were witnessing a major bleaching event that was very widespread.
Following the El Niño of 1998, widespread bleaching was observed throughout the Indian and Pacific Oceans. Most reefs have begun recovering from that catastrophe. This present event appears to be almost as serious and may prove to be equally or more devastating to western Pacific reefs by the time it is over. There are several aspects of what we are seeing that are especially disturbing. While El Niños have been observed historically, they are becoming more severe and far more frequent than they have been in historical record. Another concern is that reefs that are already stressed from other human insults such as dynamite fishing, pollution, and sedimentation are less resilient to more frequent bleaching events.
Promise in the Philippines
Most of my search for new nudibranch species over the last two decades has focused on the reefs of the Philippines (map). This area has been shown to have more species of reef fish, soft corals, and nudibranchs than any other place in the world. Here we continue to find new species of nudibranchs at the average rate of one new species per dive. During these 18 years, the reefs of Balayan Bay at the southern end of Luzon have seen many changes.
On my first trip to this area in 1992, I remember vividly the loud, concussive explosion of dynamite when I was underwater. One time it was so close and intense, I thought my eardrums had been blown out. Next to me were quivering, dying reef fish. I immediately came to the surface to ask our boatman if there was another boat nearby. There was nothing visible as far as we could tell. Often the fatal shock wave from a dynamite blast can carry a mile or more. It is not a selective or predictable method of fishing, and blasted coral and dead fish can be found far away. It is also profoundly destructive in that the living coral substrate is also blasted to hell and there is no longer adequate habitat for fish to re-colonize the depleted reef.
Since then, a transformation has begun to take place. Marine protected areas have been set up and are being strictly enforced. Recreational divers are charged a modest fee for diving on reefs and those funds are supporting conservation efforts within the municipality of Mabini. Community groups work together to make informed decisions on how to administer funds and enforce regulations. Often their regulations are stricter than national regulations. Within some areas, such as Tingloy, community groups are taking the initiative themselves. The reef of Red Palm (Pulangbuli) was made a marine sanctuary largely through the efforts of a community leader, Princess Aldovino. These regulations have forbidden any fishing or diving on the reef for more than 6 years. Despite threats from irate fishermen, Princess and other local conservation leaders have firmly held their ground.
When we dove on this reef 10 years ago it was decimated with dead coral rubble and hardly any fish. In late September I returned there as part of a joint Philippine Bureau of Fisheries and Aquatic Resources and California Academy of Sciences expedition. Several of us were granted the privilege of being the first divers to observe the reef after 6 years of complete protection. This once dead reef has made a remarkable comeback and young coral heads and healthy populations of diverse reef fishes now abound. Thanks to the heroic efforts of enlightened local people who understand that short-term sacrifice is worth the long-term benefit of conserving resources for future generations, many Philippine reefs are now healthier than when I first started working there.
However, within the last couple of weeks we had received the first disturbing news that significant coral bleaching was beginning to appear in Balayan Bay. While I had seen a few photos from the area, I still didn't have a good sense of how severe and widespread the bleaching was. I am now in Manila to help plan for a large expedition of Academy and Filipino scientists and educators to document biodiversity in the Philippines in 2011 and help promote conservation. This will also provide us with an opportunity to see firsthand, the condition of the reefs we know so well. I decided to carve out a couple of days in my schedule to visit the reefs that I have been observing for two decades, to see for myself how widespread the bleaching had become. I had been here just a few months earlier in May and had a vivid memory of what it looked like then.
Our first dive was right off the beach from Club Ocellaris, where we were based. Immediately, I saw a few bleached corals and the more we looked the more we saw. Overall, 5-10% of the corals were pale and discolored. It wasn't nearly as bad as what I had seen in Thailand, but here it was in my own backyard and it felt personal. Dives at our other key sites revealed the same pattern.
At a site called Bethlehem, I was especially curious to see how one massive coral colony was doing. This colony is about twenty feet high and spans a length of 100 feet and is probably hundreds of years old. When I saw it, I could not believe it. Instead of a uniform gray-brown colony, there were patches of white everywhere. It reminded me of a dusting of light snow in an early fall storm. I looked carefully and the coral polyps were still alive, just devoid of their symbiotic algae. On another site, Koala, it wasn't just the hard corals that were bleached but also soft corals and sea anemones. It was patchy but some of the patches of bleached corals were very extensive. The sea anemones were especially poignant as their clown fish residents look like little nemos living in a glass house.
I am optimistic that most of the bleaching will be temporary and that the majority of corals will recover rather than die. They probably dodged the bullet this time, but what will the future decades of impacted reefs and climate change look like? My colleague Charlie Veron, the world's foremost coral taxonomist, has suggested that we may be the last generation to have seen healthy reefs. I hope this is not the future, but we are seriously concerned. The threat is immediate and real.
To me the saddest part of what I saw is that even when local communities make every effort to conserve their reefs, what the developed world is doing a world away now impacts Princess' reef and every other reef in the region. Global climate change means more bleaching, more dead reefs, and more ocean acidification that will severely inhibit growth of the coral skeletons that build reefs. Reefs are dying and people's ability to sustainably use coral reefs is being seriously compromised.
There is great urgency to move to a non-carbon producing energy economy, yet disturbingly little is happening to make the changes we require, that life on our planet desperately needs. The U.S. Congress is failing to muster the leadership and political courage to make the necessary changes to successfully ameliorate the situation. The American people are not sufficiently scientifically literate enough to make informed decisions and chose to ignore the facts about the severity of our present planetary disequilibrium. Short-term greed seemingly trumps implementation of long-term solutions. It truly is business as usual. In Tingloy, Princess and members of her community have figured out that short-term sacrifice is the path to a future for the next generations. Why can't the citizens of one of the richest and best-educated nations do the same?
Crossposted with ClimateStoryTellers.org