Restoring Coral Reefs Is Possible and Surprisingly Fast

Written By Dr. Mercola
Origianl posting on

Coral reefs make up less than one-quarter of 1 percent of the Earth’s surface,1 yet supply resources worth an estimated $375 billion annually, according to the International Union for Conservation of Nature (IUCN).2 More than 500 million people around the world depend on coral reefs for protection from storms, food, jobs and recreation, and they provide a home to more than 25 percent of fish species and 800 hard coral species.

As for their importance to their surrounding ecosystems, it is immense, and the sheer diversity of species that depend on coral reefs for spawning, breeding and feeding is equally impressive. There are 34 recognized animal phyla, for instance, and 32 of them are found on coral reefs (even rain forests count only nine different phyla among their midst).3

Sometimes referred to as “rain forests of the sea,” it’s estimated that coral reefs may support up to 2 million different species and act as essential nurseries for one-quarter of fish species.

Coral reefs also serve as carbon sinks, helping to absorb carbon dioxide from the environment, and represent an irreplaceable source of protection for coastal cities. Their importance as a food source is also considerable, as healthy coral reefs can provide about 15 tons of fish and other seafood per square kilometer (.38 square mile) per year.4

Unfortunately, corals are in severe decline. According to conservation organization World Wildlife Fund (WWF), two-thirds of coral reefs worldwide are under serious threat and another one-quarter are considered damaged beyond repair.5 There may, however, be hope, even for damaged reefs, as new technology offers a chance for reefs to regrow at a surprisingly fast pace.

Biorock Technology Restores Coral Reefs

In 2000, it was stated at the International Coral Reef Symposium that about 94 percent of Indonesia’s coral reefs were severely damaged. This included Pemuteran Bay, where the once-thriving coral reef was largely barren. Biorock technology proved to be the answer, restoring the reef in just over a decade:

“Pemuteran formerly had the richest reef fisheries in Bali. The large sheltered bay was surrounded by reefs teeming with fish. The natural population increase was greatly augmented by migration of fishermen from Java and Madura, where inshore fisheries had been wiped out by destructive over-exploitation.

Destructive methods, like use of bombs and cyanide followed their use in other islands, and steadily spread until most of the reefs had been destroyed. The offshore bank reefs that had been dense thickets of coral packed with swarms of fishes, were turned into piles of broken rubble, nearly barren of fish.”6

The Karang Lesteri Project, highlighted in the video above, began in June 2000, when the first “coral nursery” was built at the site. Ultimately, 70 Biorock coral reef structures of different sizes and shapes were planted in the area, restoring the area’s diversity and ecosystem. Formerly known as Seament and Seacrete, Biorock was developed by the late professor Wolf Hilbertz and scientist Thomas Goreau, president of the nonprofit organization the Global Coral Reef Alliance (GCRA).

Projects are now being operated in Indonesia, Bali, Jamaica, the Republic of Maldives, Papua New Guinea, Seychelles, Phuket, Thailand and elsewhere. The technology starts with metal structures that are planted into the reef. Transplanted fragments of live coral (that have been damaged by storms, anchors or other mishaps) are attached and the structure is fed low-voltage electricity to accelerate the growth process. GCRA explains:7

“The Biorock® process … is a new method that uses low voltage direct current electricity to grow solid limestone rock structures in the sea and accelerate the growth of corals providing homes for reef fish and protecting the shoreline. The electrical current causes minerals that are naturally dissolved in seawater to precipitate and adhere to a metal structure. The result is a composite of limestone and brucite with mechanical strength similar to concrete.

Derived from seawater, this material is similar to the composition of natural coral reefs and tropical sand beaches … This patented process increases the growth rate of corals well above normal, giving them extra energy that allows them to survive in conditions that would otherwise kill them. At the same time these structures attract huge numbers of fish, and also provide breakwaters that get stronger with age.”

GCRA states that Biorock reefs grow at a rate of 1 to several centimeters of new rock per year, which is about three to five times faster than normal. While artificial reefs, which are sometimes made by sinking ships, planes, cars, concrete or other man-made materials, will sometimes attract fish and sponges that settle on their surface, the Biorock reefs ultimately turn into true, living coral reefs, courtesy of the growth of limestone. According to GCRA:8

“Coral larvae, which are millimeter-sized freely-swimming baby corals, will only settle and grow on clean limestone rock. This is why conventional artificial reefs made of tires or concrete rarely exhibit hard coral growth. But, when these coral larvae find a limestone surface, they attach themselves and start to grow skeletons. Mineral accretion is exactly what they are searching for. As a result, there are very high rates of natural coral settlement on Biorock structures.”

Is Biorock Sustainable, and Does It Withstand Hurricanes?

Funding to take Biorock to the next level is limited, with most projects so far acting as pilot projects to demonstrate how the process works. And some coral reef experts, such as Rod Salm, senior adviser emeritus with the Nature Conservancy, have suggested the process is too cost prohibitive to work on a large scale.9 Others have pointed out that its dependence on electricity could also be problematic environmentally, although some of the structures are powered via solar panels.

Further, GCRA evaluated damage to the structures in the Caribbean after hurricanes Hanna, Ike and Irma and found them to be remarkably unfazed. While even large shipwrecks in South Florida were damaged or moved during hurricane Andrew, for instance, the Biorocks’ open frameworks allowed water to flow through the structures, sparing them the brunt of the damage.

“For growing corals, we make open frameworks, so the corals can benefit from the water flow through the structure, just as they do in coral reef,” GCRA notes. “As a result of their low cross section to waves, they dissipate energy by surface friction as waves pass through them, refracting and diffracting waves rather than reflecting them. Their low drag coefficient means that they survive waves that would move or rip apart a solid object of the same size.”10

In research published in the journal Revista de Biologia Tropical by Goreau and colleagues, it’s noted that artificial reefs are often discouraged in shallow waters because of concerns that they could damage surrounding habitat during storms. However, in the case of the Biorock restorations, “the waves passed straight through with little damage,” and the researchers said the “high coral survival and low structural damage” after hurricanes suggests the process is effective even in areas that may be hit by storms.11

Another study by Goreau, published in the Journal of Marine Science and Engineering, suggests Biorock electric reefs are able to grow back severely eroded beaches in just a few months. The study noted:12

“Biorock reefs stimulate settlement, growth, survival, and resistance to the environmental stress of all forms of marine life, restoring coral reefs, sea grasses, biological sand production, and fisheries habitat. Biorock reefs can grow back eroded beaches and islands faster than the rate of sea level rise, and are the most cost-effective method of shore protection and adaptation to global sea level rise for low lying islands and coasts”

What’s Causing Coral Reefs to Die?

Coral reefs are facing numerous threats, including rising water temperatures that lead to coral bleaching, in which coral reject symbiotic algae, turn white, and are at increased risk of dying. Overfishing, which disrupts the ecological balance in the reef, as well as destructive fishing practices, such as the use of cyanide, dynamite, bottom trawling or muro-ami (which involves the use of nets and banging the reef with sticks), are also threats, WWF notes.13

Reefs are also harmed by tourism via boating, anchor drops and people diving, snorkeling around and touching the reefs (or collecting coral), as well as construction, mining and logging, which send excess sediment into rivers and the ocean, where it blocks precious sunlight from reaching the coral reefs. There’s even a live rock trade, in which coral is mined for building materials or to sell as souvenirs, with no regard for the destruction it causes to the planet.14

Pollution is another major threat, including that from industrial farm runoff, which is fueling the growth of marine algae blooms, which alter the food chain and deplete oxygen, leading to sometimes-massive dead zones. Even the sunscreen chemical oxybenzone is known to kill off coral reefs. It’s estimated that between 6,000 and 14,000 tons of sunscreen enter coral reef areas worldwide every year.

Much of this sunscreen contains oxybenzone, which research found to be damaging at minute levels — just 62 parts per trillion, or the equivalent of one drop of water in 6.5 Olympic-sized swimming pools.15 Aside from entering the water on swimmers, oxybenzone gets washed down the drain when you shower, entering sewage systems. Once in the environment, as a study published in the Archives of Environmental Contamination and Toxicology revealed, there are four key ways oxybenzone is damaging coral reefs:16

  • Exacerbates coral bleaching
  • Damages coral DNA, making them unable to reproduce and triggering widespread declines in coral populations
  • Acts as an endocrine disrupter, causing baby coral to encase themselves in their own skeletons and die
  • Causes gross deformities in coral, such as coral mouths that expand five times larger than normal

Other Techniques Restoring Coral Reefs

Numerous innovative programs are underway with the goal of restoring the world’s coral reefs. The Coral Restoration Foundation is using a program called the coral tree nursery, which is based on the fact that coral are able to grow and reproduce via fragmentation. That is, if a piece breaks off, it can reattach and grow again, forming a new colony.

Their program involves PVC “trees” that are tethered to the ocean floor. Coral fragments are then hung from the “branches.” The fragments come from their coral nurseries, where coral are nursed for up to nine months until they’re read to be attached to the tree. They’ve already produced tens of thousands of corals in their South Florida nurseries.17

In addition, the organization is working to create “healthy thickets of genetically diverse coral that can sexually reproduce and encourage natural recovery.” An estimated 22,000 corals have been “outplanted” in the Florida Keys, in part by volunteer divers, for this purpose.18

Other experts have suggested that releasing natural viruses, known as phages — short for bacteriophage — onto coral with bacterial disease could essentially wipe out the disease, saving the coral.19 Of course, prevention is even better than a cure, and this means taking steps to curb coral declines in the first place.

Changes to industrial agriculture that limit chemical runoff and help sequester carbon into the soil could have meaningful benefits to coral reefs. It’s estimated that one-third of the surplus carbon dioxide in the atmosphere stems from poor land-management processes that contribute to the loss of carbon, as carbon dioxide, from farmlands. This, in turn, contributes to ocean acidification that harms coral, according to Defenders of Wildlife.

“Seawater absorbs some of the excess CO2 from the atmosphere, causing the oceans to become more acidic. As a result, the oceans’ acidity has increased by 25 percent over the past 200 years. These acidic conditions dissolve coral skeletons, which make up the structure of the reef, and make it more difficult for corals to grow.”20

So, in addition to being a responsible swimmer or diver — and not touching or breaking coral — as well as using only natural, reef-friendly sunscreen, support farmers who are using diverse cropping methods, such as planting of cover crops, raising animals on pasture and other methods of regenerative agriculture. This, in addition to the innovative methods like Biorock being used to restore barren reefs, can help protect the ocean’s reefs from further damage.

Sources and References


Historical overview of impacts from land-based pollution on CBNRM as it applies to marine fisheries & coral reefs in the tropics

An historical overview of impacts from land-based pollution on
community based natural resource management (CBNRM) as it applies to marine fisheries & coral reefs in the tropics.

Paul Andre DeGeorges1,2*

1Tshwane University of Technology, Nature Conservation, Pretoria, South Africa
2Mayflower Drive, Greenbackville, Virginia 23356, USA


The purpose of this review is to provide an historic record of the author’s experience from the 1960s through the 1990s with coral reefs and the impacts of land-based pollution and other actions by man on this important ecosystem, from the islands of the Caribbean and Central America to the West/East Coasts of Africa and the Western Indian Ocean. This is tied into the concept of Community Based Natural Resource Management (CBNRM), its origins in Southern Africa tied to Africa’s mega-fauna and how it can apply to fisher communities in the tropics. It concludes that unless human population pressures and the current forms of “development and conservation” both linked to pollution and habitat degradation are addressed, the future for both man and these unique ecosystems are in jeopardy. A key to this solution is how the Developed World relates to the Developing World. It is hoped that this review will provide insight to future generations of ecologists, researchers, resource managers, politicians, donors and NGOs (non- governmental organizations) as to the issues they will confront if both mankind and nature are to have a viable future, living in harmony. Currently, they appear to be in conflict with each other and only man can resolve these issues based upon how he interacts with Mother Nature.

Read PDF

Review Article:

Land-Sourced Pollution with an Emphasis on Domestic Sewage: Lessons from the Caribbean and Implications for Coastal Development on Indian Ocean and Pacific Coral Reefs

Source: DeGeorges, 1988
Source: DeGeorges, 1988

Sustainability 2010, 2, 2919-2949; doi:10.3390/su2092919

ISSN 2071-1050

Andre DeGeorges 1,2,*, Thomas J. Goreau 1 and Brian Reilly 2

1 Global Coral Reef Alliance, 37 Pleasant Street, Cambridge, MA 02139, USA; E-Mail:

2 Department of Nature Conservation, Tshwane University of Technology, Private Bag X680, 0001 Pretoria, South Africa; E-Mail:

* Author to whom correspondence should be addressed: E-Mail:; Tel.: +1-757-854-1303; Fax: +1-703-790-1578. Received: 6 August 2010; in revised form: 5 September 2010 / Accepted: 9 September 2010 / Published: 14 September 2010

Abstract: This paper discusses land-sourced pollution with an emphasis on domestic sewage in the Caribbean in relation to similar issues in the Indian Ocean and Pacific. Starting on a large-scale in the 1980s, tropical Atlantic coastlines of Florida and Caribbean islands were over-developed to the point that traditional sewage treatment and disposal were inadequate to protect fragile coral reefs from eutrophication by land-sourced nutrient pollution. This pollution caused both ecological and public health problems. Coral reefs were smothered by macro-algae and died, becoming rapidly transformed into weedy algal lawns, which resulted in beach erosion, and loss of habitat that added to fisheries collapse previously caused by over-fishing. Barbados was one of the first countries to recognize this problem and to begin implementation of effective solutions. Eastern Africa, the Indian Ocean Islands, Pacific Islands, and South East Asia, are now starting to develop their coastlines for ecotourism, like the Caribbean was in the 1970s. Tourism is an important and increasing component of the economies of most tropical coastal areas. There are important lessons to be learned from this Caribbean experience for coastal zone planners, developers, engineers, coastal communities and decision makers in other parts of the world to assure that history does not repeat itself. Coral reef die-off from land-sourced pollution has been eclipsed as an issue since the ocean warming events of 1998, linked to global warming. Addressing ocean warming will take considerable international cooperation, but much of the land-sourced pollution issue, especially sewage, can be dealt with on a watershed by watershed basis by Indian Ocean and Pacific countries. Failure to solve this critical issue can adversely impact both coral reef and public health with dire economic consequences, and will prevent coral reef recovery from extreme high temperature events. Sewage treatment, disposal options, and nutrient standards are recommended that can serve as a reference point but must be fine-tuned to local ecology.

Download PDF