Ecology and the Environment

Why are coral reefs so important?
Answered by Robert B. Gagosian, Sylvia Earle and 1 other
  • Robert B. Gagosian

    Robert B. Gagosian

  • Sylvia Earle

    Sylvia Earle

  • Discovery Channel

    Discovery Channel

  1. Robert B. Gagosian President & CEO of the Consortium for Ocean Leadership


    Coral reefs provide a real diversity of growth for fish and plankton. In a lot of areas of the ocean, there are a number of problems with coral reefs. There is the warming issue -- ocean warming -- and there are a lot of areas that are leeched out now. There is the pollution issue, which is pretty significant. There is the fishing issue. There are a number of countries in Southeast Asia, tropical fish and other fish that are used for traditional eating and are viewed as specialty fish.

    The way they catch those fish is with cyanide. And so not only do you capture the fish -- and concentrations aren't high enough to cause damage to humans -- but it kills everything on the reef. Yes, they get the fish but it just wipes out the reef, and so those three problems -- the global warming, the issue of pollution and the issue of overfishing -- are slowly killing the reefs. And they provide this diversity in the ocean that is really very important for the future of the ocean. Sometimes, we don't realize how important this diversity is because once you lose a link in the chain, you tend to lose the chain. And one of my favorite statements is the strength of the chain is its weakest link, and if you lost that link, you have a real problem.

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  2. Sylvia Earle Founder and President, The Sylvia Earle Alliance


    Among the ecosystems that make up the fabric of life on Earth, coral reefs have a special role, in terms of the diversity that they happen to harbor. It's true in the Atlantic. It's true in the Pacific, especially in the Pacific, the Indo-Pacific, Indian Ocean as well. They're centers of diversity for whole groups of animals: fish, echinoderms, crustacea, annelids, and small groups of phyla -- the categories -- of animal life, and plants as well. The thing is, we're just beginning in the last 50 years or so to focus on what kind of creatures are there on the Earth -- the last 10 years in particular, through the census of marine life -- a concerted effort to try to find out where are the high concentrations of diversity.

    And it turns out that coral reefs really shine. I say that, knowing that the exploration of the deep sea is still in a very primitive state. And there are coral reef systems of a different sort that are in the deep sea as well. The diversity there is a big X factor. We really don't know. What we do know is from the surface to the greatest depths, there is life. And the diversity is much greater than we have anticipated, based on past history. Right now, about 250,000 individual species of organisms have been identified in the sea. And a disproportionate number occur in coral reefs. That may be, in part, a reflection of where the concentration of scientists are. We love our coral reefs.

    We don't know much about the deep sea yet. But all things considered, the importance of what's happening to coral reefs is not just the loss of diversity. It's also that these are the big, beautiful canaries. If they're in trouble, the ocean is in trouble. If you lose a big wedge of echinoderms, a big wedge of crustacea, a big wedge of polychaete, that means we've lost resilience: the possibility that some creatures within this matrix of diversity will be able to respond to changing times, changing circumstances. That's our security blanket: the diversity of life. Where it comes down to perhaps the most important part is at the microscopic level, the microbes.

    If we sacrifice diversity there, we just make ourselves more vulnerable. And we are sacrificing diversity. The healthy reefs, healthy relatively pristine seas turn out to have a greater diversity even at the microbial level than, say, San Francisco Bay. You have a smaller number of choices of representation that can respond when things change. It's cause for real concern.

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  3. At least 25 percent of all marine species make their homes in and around coral reefs, even though these unique habitats cover only a tiny portion of the ocean floor -- less than 1 percent. Created by corals (taxonomical relatives of jellyfish and anemones), coral reefs are incredibly delicate ecosystems that need very specific conditions to flourish.

    Unfortunately, those conditions are rapidly deteriorating in modern oceans and the impact is starting to be felt in many areas of commerce. For example, since coral reefs are comparable biological hotspots to the planet's rainforests (rainforests do probably beat out reefs on their overall number of species, but they also have 20 times the space to spread out), this diversity is valuable to industries like biomedical research, fishing and tourism. Coral reefs can also help protect coastlines from storm-generated waves, helping decrease the loss of life and dollars.

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