BY KATIE VALENTINE
Coral reefs provide substantial protection against wave energy, lessening the impact of sea level rise and intense storm surges for 7 million people in the U.S. alone, according to a new report.The report, published this week in the journal Nature Communications, reviewed 255 studies on the protective nature of coral reefs and found that reefs reduce wave energy by 97 percent on average, causing the waves that reach the shoreline to be significantly calmer than they would have been without the reefs. Michael Beck, one of the authors of the report and senior scientist for the Nature Conservancy, said he was surprised at the 97 percent average for reef wave reduction. He said he knew it would be a large number — other studies have shown that reefs are effective at reducing wave energy, but none yet had quantified it ocean-wide — but he didn’t know just how big.
The report also found that worldwide, 197 million people are protected by reefs, and that maintaining the health of coral reefs is far less expensive than installing artificial defenses — according to the report, the median cost of building artificial wave defenses is $19,791 per meter, while the median cost of coral restoration projects is $1,290 per meter. Beck said the Nature Conservancy is working in a coral reef in Grenville, Grenada to build back the reef’s crest, the highest part of the reef that’s the most important for wave-breaking. He said degredation of the reef crest, which has been caused over the last 50 years by climate change, pollution, and sand mining, can explain a “huge amount” of the erosion and sedimentation that’s been occurring in the bay.
“A variety of causes has led to a little bit of degradation in height in the reef, and when you’ve lost that height in the reef, you can suddenly explain a huge amount of problems that have been happening,” he said.
Beck’s team has been been building back the reef in Grenada by using old coral rubble and concrete blocks, then trying to regrow the living coral on those structures. Projects like that, he said, are important to coral reefs’ survival — though coral is threatened gravely by climate change and ocean acidification, he said reefs “can be resilient” and recover from stresses like bleaching. He pointed to a mass bleaching event that occurred in 1998, after El Niño drove up water temperatures worldwide, as evidence. Though many were worried the reefs wouldn’t bounce back from this event, which was the most extensive and severe in history, certain reefs did recover, despite significant losses worldwide.
“Those reefs that were managed well, where you reduce the other stressors like pollution and overfishing, recovered,” he said. “Living coral came back and came back in quite good abundances in places were coral reefs were managed well.”
That event points to the need for better reef management, Beck said, especially now, as reefs around the world continue to suffer the effects of warming oceans, pollution, fishing practices and other impacts. Elkhorn coral, which play an integral role in the reef ecosystem of the Florida Keys, are being killed off by White Pox disease, which one researcher says is likely caused by untreated human sewage that enters the ocean through leaky septic systems in Florida. And outside of the 1998 event, scientists have found other significant evidence of coral bleaching, an effect that’s due to warmer-than-usual ocean temperatures and is likely to get worse as the ocean warms.
Other coastal and marine ecosystems provide protection from storm surge, sea level rise and erosion, but they too are struggling with human-induced impacts — in fact, Beck said coral reefs are in better shape worldwide than oyster reefs and mangrove forests. These coastal ecosystems have also been found to be a cost-effective way of providing protection — an April report noted restoring ecosystems like oyster reefs can create more jobs than offshore oil development and provide $15 in net economic benefits for every $1 invested.
Healthy coral ecosystems support local businesses and economies, as well as provide jobs through tourism and recreation. Every year, millions of scuba divers and snorkelers visit coral reefs to enjoy their abundant sea life. Even more tourists visit the beaches protected by these reefs. Local economies receive billions of dollars from these visitors to reef regions through diving tours, recreational fishing trips, hotels, restaurants, and other businesses based near reef ecosystems. One estimate places the total global value of coral-reef based recreation and tourism at $9.6 billion of the total global net benefit of coral reefs. [a]
For example, in the US, reef-related recreation and tourism account for an estimated $364 million in added value to Hawai`i's economy each year and its nearshore reefs annually contribute nearly $1 billion in gross revenues for the state. [b] Caribbean countries, which attract millions of visitors annually to their beaches and reefs, derive, on average, half of their gross domestic product from the tourism industry. [c] In Southeast Asia, it is estimated that each square kilometer of healthy reef (in areas with tourism potential) has a potential net benefit of $23,100 to $270,000. [d]
Diving is one of the key components of reef tourism and recreation; divers generally look for high-quality coral reef habitats (as indicated by live coral coverage), coral and fish diversity, and water clarity. As a result, half of all diving in the Caribbean occurs within the region's marine protected areas, although these reefs represent a small fraction (about 20 percent) of all reefs within the region. Divers in the region have indicated a willingness to pay an average of an additional $25 per diver per year to keep the Caribbean coral reefs healthy. [e] One estimate predicts a loss of growth in the Caribbean dive industry of between 2 and 5 percent by 2015 due to reef degradation, which would result in a region-wide loss of annual net benefits of between $100 and $300 million. [e]
Despite their great economic and recreational value, coral reefs are threatened by a number of factors. Recreation and tourism are "high value" industries that are especially sensitive to reef condition, and thus particularly vulnerable to degradation. [f] Once coral reefs are damaged, they are less able to support the many creatures that make their home on the reef and in turn lose value as a destination for tourists. Reef degradation has a direct economic impact on people whose livelihoods rely on reef tourism.
The genetic diversity found in coral ecosystems is unparalleled and this diversity has proven beneficial for humans through the identification of potentially beneficial chemical compounds and through the development of medicines, both derived from organisms found in coral ecosystems.
Many species found in coral ecosystems produce chemical compounds for defense or attack, particularly the slow-moving or stationary species like nudibranchs and sponges. Searching for potential new pharmaceuticals, termed bioprospecting, has been common in terrestrial environments for decades. [a] In fact, nearly half of the medicines in use today have their origins in natural products, mostly derived from terrestrial plants, animals, and microorganisms. [b] However, bioprospecting is relatively new in the marine environment and is nowhere close to realizing its full potential. [a] Creatures found in coral ecosystems are important sources of new medicines being developed to induce and ease labor; treat cancer, arthritis, asthma, ulcers, human bacterial infections, heart disease, viruses, and other diseases; as well as sources of nutritional supplements, enzymes, and cosmetics. [b] The medicines and other potentially useful compounds identified to date have led to coral ecosystems being referred to as the medicine cabinets of the 21st century by some, and the list of approved and potential new drugs is ever growing.
However, this focus on coral ecosystems for medical properties is not unique to the 21st century. The unique medical properties of organisms found in coral reefs was recognized by Eastern cultures as early as the 14th century; tonics and medicines derived from seahorse extracts continue to be in high demand for traditional medicines. [b] The gall bladder of several fish species were used in Palauan traditional medicine to treat venomous stings of other marine organisms, such as stonefish. [c] While knowledge and use of some traditional medicines has been lost, there is renewed interest within modern medicine in researching some of these treatments.
Toxins provided by reef creatures are of particular interest in present day pharmaceutical research. Stonefish, sea snakes, box jellyfish, cone shells, and pufferfish contain some of the most toxic compounds presently known to man. These chemical compounds are being studied by researchers, and some have already been used to develop medicines or cosmetics. For example, cone snail neurotoxin is showing promise as a powerful painkiller. [a]
Other types of chemical compounds are also proving fruitful. The antiviral drugs Ara-A and AZT and the anticancer agent Ara-C, developed from extracts of sponges found on a Caribbean reef, were among the earliest modern medicines obtained from coral ecosystems. [b] The anti-cancer properties of a number of additional compounds derived from organisms found in coral ecosystems are also being studied. Chemicals derived from Caribbean sea-whip corals have shown skincare, painkiller, and anti-inflammatory properties and a compound derived from a Pacific sponge has lead to testing of over 300 chemical analogs for anti-inflammatory properties. [a], [d] Kainic acid, which is used as a diagnostic chemical to investigate Huntington's chorea, a rare but fatal disease of the nervous system, was isolated from organisms on a Japanese reef. [e] Australian researchers have developed a sun cream from a coral chemical that contains a natural "factor 50" sun block. [e]
To watch a short video clip about these NOAA discoveries, clickhere.
NOAA is even playing a role in the discovery of new medical compounds. A research team, including NOAA scientists at the Hollings Marine Laboratory, has discovered new compounds derived from a sea sponge and corals. One compound eats away at the shield bacteria use to protect themselves from antibiotics. The second discovery was compounds that fight some of the worst infectious bacterial strains. [e]
Besides being the source of potentially useful chemical compounds, the porous limestone skeleton of corals has been tested as bone grafts in humans. Pieces of coral set into a fracture act as a scaffold around which the healing can take place. The implant eventually disappears, absorbed by the new growth of bone. Rates of rejection are much lower than with artificial grafting materials. [e]
It should be noted that, aside from the compounds mentioned here, there are likely many other compounds under development which have not yet been disclosed to the wider public. It is safe to say that the published research is only the tip of the iceberg when it comes to the pharmaceutical possibilities presented by compounds derived from creatures found in coral ecosystems, including the corals themselves. Thus, it is nearly impossible to predict what the future economic benefits of bioprospecting will be, as more potentially valuable medical compounds are isolated from organisms found in coral ecosystems. This aspect of reef value was not incorporated into the estimated $5.5 billion total global value of coral reef biodiversity, but is certainly both a consideration for the economic value of coral reefs and the costs to society if reefs are lost. [f]
*Unless otherwise noted, all monetary values presented are in US Dollars.