Reefs in Peril: Can We Save These Beautiful Marine Ecosystems?

People who study coral reefs tend to have an emotional attachment, says Dr. Knowlton.© Getty Images

Dr. Nancy Knowlton is a coral reef scientist who studies their ecology and evolution, including the impact of climate change. The founding director of the Center for Marine Biodiversity and Conservation at the University of California, San Diego, she is also a professor at Scripps Institute of Oceanography. Her contributions have been crucial to the advancement of coral reef science.

Today, Knowlton holds the Sant Chair in Marine Science, recently awarded by the Smithsonian Institute’s National Museum of Natural History in Washington D.C. Occupying the museum’s first funded chair in marine sciences, Knowlton will provide leadership to the Smithsonian’s Ocean Initiative, an interdisciplinary move to foster greater public understanding of ocean issues.

A chat with Knowlton is like opening a trunk of coral knowledge. The conversation revolved around a recently released article Knowlton co-authored in the journal Science entitled “Coral Reefs under Rapid Climate Change and Ocean Acidification.” The piece presented a dire scenario of increasing decline and loss of coral reefs, based on the best available scientific information and the most positive climate change and carbon emission scenarios of the UN’s Intergovernmental Panel on Climate Change (IPCC).

“Ocean acidification” is a recently introduced term for an observed reduction in seawater pH. It is triggered by the absorption of atmospheric carbon dioxide (CO2), which reacts with naturally occurring carbonate ions in the ocean, to produce carbonic acid. The change in chemical conditions affects corals and other organisms that need carbonates to build their calcium carbonate skeletons. The phenomenon, together with climate change, increases ocean temperatures and more frequent bleaching events might be too much for coral reefs to handle.

E Magazine: The just released Science paper, which you coauthored with 16 of your colleagues from around the world, points to an almost inevitable coming disaster for our reefs.

Knowlton: If we don’t do something to limit CO2 emissions, yes.

How do you see the status of coral reefs in the U.S. in particular? We’re having all these problems globally with bleaching and acidification, but how are our U.S. resources?

With high acidity levels, coral reefs simply can”t adapt.

Well, the situation in the U.S. isn’t really much better. Some of the reefs in the Florida Keys and the main Hawaiian Islands aren’t in particularly good shape, nor are they all that good in the U.S. Virgin Islands and Puerto Rico. They’re about average for the planet, which is not good. The exceptions are some of the isolated coral reef atolls that the U.S. has jurisdiction over, such as Palmyra Atoll and Kingman Atoll and Jarvis and Howland, the main islands in the Central Pacific. These are really far away from people and therefore haven’t been fished. The northwest Hawaiian Islands also, for that matter, haven’t really been fished and they’re protected. The Northwest Hawaiian Islands are now part of a very large Marine Protected Area, and the other places I just mentioned are protected by the U.S. Fish and Wildlife Service.

You can go dive in those places and the reefs are in very good shape as are the fish populations. So, in some of the far corners of the planet where the U.S. has jurisdiction, reefs are in good shape. But anywhere where there’s substantial human use in the U.S., reefs are in bad shape.

These coral reef areas you mention don’t have a lot of protection, do they? I was reading in another Science paper that in the Florida Keys and the main Hawaiian Islands, the government hasn’t supported programs to increase protection levels.

The Northwest Hawaiian Islands are actually well protected because they’re part of a new largely not-take Marine Protected Area. The Florida Keys have a whole series of different levels of protection but the amount of actual no-take protection, where fishing is prohibited, is relatively small. There’s also water-quality issues; particularly in the Florida Keys. The combined effects for most of the Florida Keys are not good.

Yes, I was talking to someone doing coral reef monitoring there and they are talking about two percent coral cover.

Well, that’s very low. I haven’t heard that figure, but that’s extremely low.

And they blame it basically on water quality.

Well, it’s a combination of things. Some people blame it mostly on water quality. Some people blame it on overfishing. Both have the potential to really destabilize coral communities directly or indirectly. The relative balance of the two varies from place to place. I’m not really an expert on the Florida Keys, so I wouldn’t want to say too specifically what I think is the relative balance of those two culprits. In general, it varies from place to place. Overfishing is a huge problem in a lot of reefs.

But it’s more of a combination of factors isn’t it?

Well it’s usually a combination of factors, and in fact that’s kind of characteristic of the threats to coral reefs. And of course it’s a combination of local factors, namely water quality and overfishing, with global factors, mainly climate change and now acidification.

But, like you were saying, we still see that in more remote and pristine locations, where there is none of these local threats, or reduced local threats, the reefs are doing well.

Dr. Nancy Knowlton occupies the Smithsonian”s first funded chair in marine sciences.

Yes. And that’s a very important lesson. It means that it’s not hopeless yet, and that by instigating good local care of reefs we can forestall the effects of more global pressures. It buys us time essentially; in terms of dealing with these global pressures, which we do have to deal with. Eventually, as that paper in Science indicates, if we don’t do something about CO2 emissions we’re going to lose reefs. It’s just basic chemistry.

Acidification [caused by absorption of CO2 into ocean water] is actually really scary. If you change the basic chemistry of the ocean, then you just make it very difficult for any kind of skeletal-accreting organism to persist in any kind of healthy condition. So essentially, any organism that secretes a carbonate skeleton can do very little to adapt to high acidity. They just become replaced by organisms that don’t secrete skeletons, which means no coral reefs.

It’s hard to predict what exactly would go extinct, but increasingly you’d get less and less. See, coral reefs are sort of like cities, they’re a kind of balance between growth and destruction, and if you keep reducing growth and increasing destruction, you eventually wind up with nothing left. It’s net growth that is really the key feature. You need to have positive net growth for reefs to persist.

How are scientists rising up to this challenge? How are coral reef scientists trying to incorporate these predictions into their research themes?

A lot of scientists are working in the topic and finding various things that can be done. I am not really arguing th

at every single scientist should be working on these specific problems. I am a big believer in the combination of basic and more applied research as being the best strategy.

But there are plenty of coral reef scientists that are working on issues of bleaching and disease. The acidification work is really just getting started, because I think it’s only relatively recently that people started to worry about acidification. If you were to go to the Coral Reef International Society for Coral Reef Studies meeting, [they have a big meeting once every four years and the next one is in June 2008 in Fort Lauderdale, Florida] or actually just look at the topics of the sessions, you’d see that there’s quite a bit of attention being paid to studies that relate to the health of coral reefs.

How about collaboration between scientists? I’ve seen more collaboration now, evidenced in this type of multi-authored papers, like the one you just published.

I think that’s true in general, I don’t think that’s specifically related to coral reefs. I think collaboration between scientists is just in general more common, because a lot of these problems require a complex array of expertise, and the best way to do that is instead of having one person try and do everything, have different experts team together to create a product.

How about collaboration between the scientific community, the media and policy makers to really find change?

Well, I think coral reef scientists as a group I can speak for most specifically, are now much more outspoken about what they think is happening to coral reefs and make an effort to communicate with the media and give informal talks or formal testimony before Congress. I think the situation is so dire that most scientists are getting involved in finding solutions.

It’s a very different situation than when I started studying coral reefs back in the 1970s, when people really didn’t worry about the long-term future of corals. People were free to study whatever they thought was interesting, and now I think people feel a kind of moral duty to try and protect reefs. People who study coral reefs usually like them and have an emotional attachment, because reefs are so beautiful, so spectacularly diverse. And most of us who are older than 40 have seen reefs just catastrophically collapse during the course of their professional careers. So, it’s hard to watch all the ecosystems you study go down the drain without being compelled to do something about it. It becomes a moral issue.

Have you seen progress as a result of all this pressure from the scientific community?

Certainly there’s a lot more attention being paid to setting up Marine Protected Areas. There’s more attention associated with water quality and climate change. But I don’t feel that people are really coming to grips with the scale of the problem and what needs to be done. But I think at least people are recognizing that the issue is there. The first step is to recognize that there’s a crisis; the second step is to figure out what to do about it. At least we’re at the stage where people recognize that there’s a crisis.

And there has to be a lot of different areas united to be able to create a change.

It’s not really just the scientists, you know. Scientists don’t make policy. They can say what the science implications are for various policy options, but making policy involves bringing in social scientists, economists, people who study government. There’s a lot of different things that have to be considered when formulating policy. But scientists have an obligation to say what the likely, in this case, ecological consequences of different policy actions or non-actions will be. I think that’s appropriate. Then as citizens, any scientist can say what they think the policy should be, but as scientists their role is to say what science tells you about the consequences of different ways of approaching the problem.

It’s a collaborative effort, isn’t it?

Yes. Scientists as citizens can vote and make their personal views known, but as professional scientists their role should be to advice policy makers and the public of what the consequences of doing A, versus doing B are. What scientists can say very clearly is that if we don’t come to grips with greenhouse gas emissions then we are going to lose reefs.

And you believe that scientists are getting up to speed on reefs so they can advise policy-makers?

Yes. I think there are very few coral reef scientists who aren’t very aware of what’s going on. Decline of coral reefs began in the 1980s, so it’s now been almost 30 years where we’ve been watching reefs going down and down and down. In fact, many students who have gone into studying coral reefs are motivated by wanting to help the situation.

As chair of marine science at the Smithsonian now, what initiatives in particular are you planning to try and deal with this?

Well, I have my own individual research program which is on coral reefs, but I think more broadly, in terms of communicating with the public, the Smithsonian has a lot of opportunities, both in terms of the new Ocean Hall that will be opening in September and also the Ocean Portal, which will be an Internet site where a lot of these issues can be presented. There will also be resources for people wanting to go further. The Ocean Portal is a kind of virtual meeting place for people who want to know more about the ocean and do something about improving ocean health.

What do you think about the restoration initiatives that are being tried with electricity or the implanting of new artificial reefs? Do you think we’re losing time with those experiments or do you think they might contribute to helping?

The one big issue with restoration is that there’s no point in doing anything about it, if you haven’t eliminated the original causes of coral reef decline. Because then the same things will happen with the restored reefs, as with the original reefs. So you have to have created a situation where the environmental conditions are good for the coral communities for restoration to even be considered. Once you’ve done that then, yes, restoration has a role to play.

If a ship hits a reef or a hurricane passes and does a lot of damage in a localized place, the causes of decline are specific events. When they’re no longer an issue, then restoration is quite possible. Big-scale restoration is, even under the best of circumstances, (and this is when the conditions are favorable for reef growth), pretty hard. It’s just very labor intensive. Therefore, when you’re talking about the geographic scale to which reefs have declined, it’s really counterintuitive. I think restoration can work in specific, well-defined situations where the conditions are good for reef growth, but the original cause of decline has been eliminated and the physical scale of the area that’s been degraded is viable. Beyond that, you can try.

People have talked about restoring Caribbean reefs for example, by reintroducing larvae of Diadema antillarum, which is a very important seaweed eating sea urchins that largely died-off during a mass epidemic in

the 1980s. The idea is that eventually, once they’re established, they could spread and help reefs beyond their initial site of introduction. Other people have talked about using heat-resistant algal symbionts of corals to make them better able to resist bleaching and some have even talked about vaccinating corals against disease. Actually, some coral diseases can be treated on a local basis, but almost everything you do is very hard to scale up to, say, a Caribbean-wide strategy. Restoration has its role, but in general, we need more attention to improving conditions. That means lowering fishing pressure, improving water quality and dealing with greenhouse gas emissions. It’s more cost-effective than restoration initiatives, unless very specific conditions exist.

So we need local measures coupled with an international campaign to reduce CO2 emissions?

Yes; and reducing CO2 on a national basis, too. The U.S. is a major contributor to greenhouse gas emissions. In the long run, if you don’t do that work, restoration is kind of pointless.

Many countries depend on reefs as food resources, for shelter or for tourism. Would you say that we should be moving human use to other resources? Given this inevitability on the demise of resources, do you think we still have a shot of keeping the lifestyle associated with reefs?

Tourism, if properly managed, can be good for reefs. There are human impacts, but if people can see reefs, they will also realize what they’re losing. Also, many developing countries, which have very extensive coastlines, don’t really have the option of turning to something entirely different. I think tourism can be managed in a way that is reef friendly. So I don’t think we have to give up on tourism, but we have to do tourism in a way that is less destructive to reefs. The biggest problem with tourism on reefs is when you get vast numbers of poorly trained people in the water, stepping on reefs and breaking the corals off, or dropping anchor all over the place. And tourism is a problem if you get a lot of poorly regulated development in terms of resort building on land, which has a lot of effect on water quality. It can also affect fishing, if those resorts are pulling most of the food for the tourists from the reef. So you have to think about it in an integrated way. But there’s actually no reason why you can’t have tourism that is relatively reef friendly.

I was referring not only to tourism, but also to the communities that depend on reef resources for their lives.

Marine Protected Areas offer really important ways of managing reef fisheries so that some places have some a stable large stock of big fish that can keep the species going. So you need to manage reef fisheries, because the natural tendency of people is just to fish until everything is gone. You have to have some kind of management scheme. Marine Protected Areas are one such scheme; there are others that people have argued might work better, particularly in the developing country context. But you have to have something, some kind of way of regulating resource extraction.

But you wouldn’t go yet to the scenario of OK, let’s try and change our whole relationship to coral reefs as humans?

I don’t think that’s realistic. In a developing country context that’s not realistic because those countries need to feed their populations and provide sources of income for them. And in many developed countries coastal resources are a huge part of the economy so it’s just not realistic. And then I think it’s also unrealistic to, say, outlaw people going into the water, even in a developed country context. We can’t make it illegal for people to swim over coral reefs; that’s not realistic. Somehow you need to integrate human wellbeing in its broader sense and reef wellbeing. I don’t think building some kind of wall between people and reefs in a kind of all-or-nothing fashion is a realistic way to think of the future. I think rather we need to think about how we can make human use compatible with healthy reefs. And I think that we have some solutions that are already out there.

So, you still have hope?

Well, I have. You have to have some sort of hope. Hope has more to do with how you feel that human society is going to respond, rather than whether there are solutions. I think all scientists feel that there are solutions. It’s more of a question of political will and that’s where some people are more optimistic than others. But if we actually took the steps necessary to make sure the reefs would persist, then reefs would recover. All is not lost, very little in the way of reef organisms have gone extinct. All the players are there but we have to start doing stuff really fast. We don’t have any more time.

So, you think even with acidification and global warming if we took the steps now, the correct steps, we would have a chance of not losing reefs?


KATHERINE CURE, who holds a master’s degree in marine biology, studies reefs from her perch as an intern at E/The Environmental Magazine.

CONTACTS: Dr. Nancy Knowlton