Health

Why our coral reefs need hope

In the tropical waters off the coast of Indonesia, a free-swimming coral larva attaches itself to an underwater rock and starts to grow. The larva grows into a coral polyp, then a colony that matures and releases larvae that colonize other rocks. In time, it helps to create one of nature’s most spectacular ecosystems: a coral reef. Orange, blue, and sparkling-silver fish dart around a seascape of vibrant greens, yellows, pinks, reds, purples, and countless combinations of the full rainbow of color. There are few places on our planet as otherworldly and intensely colorful as a healthy coral reef.

Such a paradise takes time to create. Coral grows very slowly—some species grow less than an inch a year—so a coral reef can take thousands of years to fully develop. But it’s worth it. “Coral reefs are the most biodiverse marine systems,” says Professor David Smith, Director of the Coral Reef Research Unit at the University of Essex and Chief Marine Scientist for Mars, Inc. “They pack 25 percent of all marine life into less than one percent of the ocean floor.” A single reef can be home to thousands of species, acting as a nursery for fish and a natural sea defense for coastlines. “Coral reefs support the livelihoods of millions of people, and are directly connected to several other key marine ecosystems,” adds Smith. This makes it all the more important to keep our coral reefs healthy.

However, in the last 20 years around half of all coral reefs have died; by 2050 nearly all of the world’s coral could be gone. “At a global level the biggest threat is climate change,” says Smith. Carbon dioxide emissions are making the oceans warmer and more acidic. Rising acidity reduces the rate at which reefs develop. Crucial to coral health are colorful algae called zooxanthellae. These algae live in coral polyps, providing coral with its bright color. The zooxanthellae photosynthesize and pass the products to their coral host providing it with its major source of food and energy. When water temperatures rise during marine heatwaves, photosynthesis is inhibited and the coral ejects them. However, without the zooxanthellae, the coral turns a ghostly white, and when deprived of the algae over a prolonged period, the coral will starve. As global temperatures increase, these “bleaching events” are happening more frequently―too frequently for the slow-growing coral reefs to recover.

“At a local level, a major problem is destructive fishing,” says Smith. Overfishing can also be devastating, reducing the numbers of herbivores, such as parrotfish, that help to control the spread of harmful algae that can contribute to coral death. Pollution caused by human activity is also a problem: oil and chemical spills, sediment and sewage discharge, and agricultural runoff can all hinder reef growth, reduce reproduction, and cause diseases that can wipe out an entire coral colony.

This is why the world’s coral reefs need help. Global action to end the burning of fossil fuels and to maintain the forests that help slow climate change are crucial to the survival of coral reefs, but for many the damage is already done. “Some reefs have to have a helping hand, or they just have no chance,” warns Smith. “That’s where restoration fits in.” Many governments, organizations, and businesses are working to regenerate damaged, dying, and dead coral reefs. One of these is SHEBA®, the cat food brand within Mars, Inc., that is deploying an innovative approach to begin the world’s largest coral restoration program at the appropriately named “Sheba Hope Reef.”

“The Spermonde Archipelago, where Hope Reef is today, was one of the most important fisheries in Indonesia and the most impacted by destructive fishing techniques,” explains Smith. More than 30 years ago, blast fishing reduced the reef to rubble. As coral larvae cannot safely attach to a constantly moving surface―like rubble―the coral did not return. “The whole area was devoid of coral,” laments Smith. “Nothing was left but a few sea urchins and a bit of algae.” SHEBA® is determined to change that. Since 2008, as part of the Mars Sustainable in a Generation Plan, Mars has been working on new ways to restore reef ecosystems. They have worked closely with marine scientists like Professor Smith to develop MARRS—the Mars Assisted Reef Restoration System—that SHEBA® is using to rebuild and restore Sheba Hope Reef.

The MARRS technique uses innovative “reef star” technology, three-foot-wide, star-shaped, steel structures coated with coral sand that are embedded into the loose rubble. “The reef stars link together to create a mesh which provides a solid platform on which corals can grow,” explains Smith. Attached to each star are around 15 coral fragments collected from nearby reefs, harvested from healthy colonies, and grown in coral nurseries—a deliberate mix that provides genetic diversity. The coral grows in all directions, stabilizing the reef, attracting marine life, and reseeding new areas. “You put the structures in,” says Smith, “and they kickstart the natural ecological process.”

The speed and the scale at which it can rebuild a reef—more than two acres of reef stars can be deployed by divers within around 30 days―make the MARRS method so unique. Over the last 13 years, MARRS has enabled over 20,000 reef stars to be laid across a number of restoration projects. Within two years, the recovered reefs have seen up to 60 percent coral cover, a 300 percent increase in the abundance of fish, and the return of vital species in the coral reef food web, such as sharks and turtles. “I predict 70-80 percent coral cover in five years,” Smith declares.

At the heart of the program is the community, where members can be directly involved with the building, maintenance, and monitoring of Sheba Hope Reef. “The whole ethos of the project was to not rely on high levels of technology,” says Smith. “It needed to use local people using locally sourced materials to provide the potential for achieving the scale needed to make a global impact.” As MARRS is rolled out to more reefs in Australia and Mexico, Sheba Hope Reef, the start of one of the world’s largest restoration projects, is an example of how positive change can happen within our lifetimes—hope is growing.

For more information about Sheba Hope Reef, and to find out how you can help restore reefs, please visit ShebaHopeGrows.com



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