Tag Archives: coral triangle

Repairing Damaged Coral Reefs

Rather than blocking waves, as a sea wall does, a reef slows them, dissipating their energy before they reach land. One estimate, from the University of California, Santa Cruz and the Pacific Coastal and Marine Science Centre, suggests natural reefs prevent $1.8bn a year of flood damage in America alone.

While natural reefs take centuries to grow, hybrid versions can be conjured up in months. The idea began with Wolf Hilbertz, an architect with an interest in marine biology. In the 1970s Hilbertz developed a technique that uses submerged electrodes to run electrical currents through seawater. This precipitates calcium carbonate and magnesium hydroxide out of the seawater, forming limestone similar to that of natural reefs. The artificial reef can become the substrate upon which a natural coral ecosystem develops…Later work with Thomas Goreau, a marine biologist, produced both a catchy name—“Biorock”—and the idea of using the stuff as the basis of coral reefs, and, in particular, for repairing damaged reefs.

In 1996 the Global Coral Reef Alliance, a charity, began using Biorock for reef repairs by growing a six-metre structure in the Maldives. Other repairs have followed in Indonesia, Jamaica and Mexico. The Pemuteran Coral Reef Restoration Project, in Bali, is more than 300 metres long and includes dozens of “nurseries” in which Biorock acts as nuclei for the natural extension of the reef….DARPA a research agency run by America’s Department of Defense, also sees hybrid reefs as a means of coastal defence—in this case protecting the country’s seaside military installations. Lori Adornato, head of DARPA’s “Reefense” project, says the goal is a hybrid reef-type system which will be maintenance-free and self-repairing. Reefense therefore involves not only creating reefs and measuring their effectiveness, but also attracting and fostering appropriate organisms to sustain the reefs’ health, ensuring they can survive even when natural reefs are suffering.

Excerpts from Ocean Reefs: Hybrid Vigor, Economist, Sept. 11, 2021

Assisted Evolution: Engineering Coral Reefs

Imagine ecologists cultivating whole new breeds of trees to restock a devastated wilderness…. Coral conservation has traditionally focused on minimizing damage from insults such as water pollution, invasive starfish, and destructive fishing or tourism. In the Caribbean, some conservationists have worked to “replant” damaged coral. But Gates and Van Oppen [two scientists]  have something more intrusive in mind. They want to try to alter the genetics of coral or the microbes that live on it. They dubb the effort “assisted evolution.”

Coral’s most remarkable characteristic—being an animal that is part plant—is also its Achilles’ heel in a hotter world. Normally, coral polyps—the individual coral organisms, which resemble a sea anemone the size of a pinhead—live in harmony with their algal partners, which help feed the polyps and give corals their bright colors. But during heat waves, the relationship sours. Overheated polyps perceive the algae as an irritant and eject them like unwanted squatters. The coral is left bleached, bone-white and starving. If the heat persists, the coral won’t take in new algae and can die.  The bond between coral and algae is complicated, however, and still not fully understood. Just 25 years ago, for example, researchers believed that coral housed just one variety of symbiotic algae. Now, they have identified hundreds. And they are just beginning to examine the role played by the coral’s microbiome, the menagerie of bacteria that inhabit a coral polyp.

Coral bleaching right.

But the complexity also offers multiple paths for scientists trying to forge a less fragile bond between coral and algae. Today, four major lines of research exist: One involves cross-breeding corals to create heat-tolerant varieties, either by mixing strains within a species or by crossing two species that would not normally interbreed. The second enlists genetic engineering techniques to tweak coral or algae. A third tries to rapidly evolve hardier strains of coral and algae by rearing them for generations in overheated lab conditions. A fourth approach, the newest, seeks to manipulate the coral’s microbiome…

In 2018, Cleves [scientist] became the first to report successfully using the CRISPR-Cas9 gene-editing tool on coral. CRISPR is often touted as a method for making genetically modified species. But Cleves says he isn’t interested in creating new kinds of coral. Rather, he sees CRISPR as a tool for deciphering the inner workings of coral DNA by knocking out, or disabling, genes one by one. He hopes to identify genes that might serve as “master switches” controlling how coral copes with heat and stress—knowledge that could help researchers quickly identify corals in the wild or in the laboratory that are already adapted to heat.

Either way, such efforts to re-engineer coral reefs make people such as David Wachenfeld, chief scientist for the Great Barrier Reef Marine Park Authority here, uneasy. The authority is supposed to protect the reef and regulate activities there. In the past, that meant a hands-off approach. Now, he concedes that “it is almost inconceivable that we’re not going to need these tools.” But, he adds, “That doesn’t mean I’m happy about any of this. This is crisis management.”

He ticks off a list of potential difficulties. Scientists focused on breeding heat-loving coral have to avoid weakening other key traits, such as coping with cold. Introducing a new coral on the scale needed to make a dent on a network of 2900 reefs spanning an area half the size of Texas is a daunting challenge. Even in its damaged state, the Great Barrier Reef still contains hundreds of millions of corals—enough to swamp the genetic impact of new coral species…

Could some kind of “super coral,” as some researchers have dubbed them, also run amok in delicate coral ecosystems.

Excerpts from  The Reef Builders, Science, Mar. 22, 2019

Ecological Hooliganism: smashing the coral triangle

Giant clams are one of Buddhism’s “seven treasures”, along with gold and lapis lazuli. China’s new rich prize their shells as showy ornaments. Each can fetch as much as $3,000, so each haul was worth a fortune to the fishermen of Tanmen, a little fishing port on the island province of Hainan in Southern China.  But Chinese government banned the clam fishing…
The ban is surely welcome. [S]ome of the most biodiverse coral reefs on Earth have been destroyed in the South China Sea thanks to giant-clam poachers. In the shallow waters of the reefs, crews use the propellers of small boats launched from each mother-ship to smash the surrounding coral and thus free the clams anchored fast to the reef. Though the practice has received little attention, it is ecological hooliganism, and most of it has been perpetrated by boats from Tanmen.

The fishermen have not been the reefs’ only adversaries. China’s huge and (to its neighbours) controversial programme since late 2013 of building artificial islands around disputed rocks and reefs in the South China Sea has paved over another 22 square miles of coral. When the two activities are taken together, Mr McManus says, about 10% of the reefs in the vast Spratly archipelago to the south of Hainan, and 8% of those in the Paracel islands, between Hainan and Vietnam, have been destroyed. Given that Asia’s Coral Triangle, of which the South China Sea forms the apex, is a single, interconnected ecosystem, the repercussions of these activities, environmentalists say, will be huge…

But still..A few streets back from the waterfront in Tanmen, elegant boutiques sell jewellery and curios fashioned from the giant clams—and clam shells are still stacked outside. And the provincial money that is so clearly being lavished on Tanmen sits oddly with the illegality of its townsfolk’s way of life. .. [I] n 2013 President Xi Jinping himself showed up in Tanmen. Boarding one of the trawlers he declared to the crew, according to state media, “You guys do a great job!” The media did not report that a year earlier the trawler in question had been caught in the territorial waters of Palau, and in the confrontation with local police that followed one of the crew members had been shot dead. In Chinese propaganda, Tanmen’s fishermen are patriots and model workers.

Over the years Tanmen’s fishermen have become part of China’s power projection in the South China Sea, an unofficial but vital adjunct to the Chinese navy and coastguard. The biggest trawlers are organised into a maritime militia ready to fight a “people’s war” at sea. Though generally unarmed, they undergo training and take orders from the navy.

They are facts on the water, and have been involved in China’s growing aggression in the South China Sea. In 2012 boats from Tanmen were part of a navy-led operation to wrest control of Scarborough Shoal from the Philippines, chasing Philippine fishing vessels away. In 2014 they escorted a Chinese oil rig that was being towed provocatively into Vietnamese waters. On land, Vietnamese expressed their rage by ransacking factories they thought were Chinese-owned. At sea, boats from Tanmen rammed and sank one of the rickety Vietnamese vessels coming out to protest.

Mysteriously, though, the giant trawlers of the Tanmen militia are now rafted up, their crews sent home. Perhaps China is keen to lower tensions in the region….A policy introduced in January aims to cut the catch from China’s fishing fleet, the world’s largest, by a sixth, in the name of sustainability. That will hit Tanmen’s fishermen hard, making them less willing to defend China’s claims. Francis Drake would have understood: pirates are patriotic, but usually only when it pays.

Excerpts from Clamshell Phoneys, Economist, Mar. 25, 2017