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The Mega el Niño – How to Protect Our Coral Reefs (Part 2)

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What to Do About our Dwindling Coral Reefs?

In the previous post, I outlined what may be coming for coral reefs as the current el Niño does its thing. The news is not good. But the longer-term news is even less good, and we need to recognize that fact. Even if the climate talks in Paris this December (CoP21) are wildly successful and a treaty gets signed that will keep global warming within +2oC this century (the stated goal), warming and acidification will continue at least to century end, and the destruction of coral reefs will also continue. It’s not a pleasant scenario to contemplate, although it is a lot better than if we are unsuccessful in Paris and warming and acidification go on unabated.

Many scientists concerned about the plight of coral reefs have recognized that the best Paris outcome is not really satisfactory for these amazing and immensely valuable ecosystems. So there are calls for even more stringent goals in Paris and beyond. Lowering atmospheric concentrations of CO2 to 350ppm is a scientifically defendable and worthwhile target – with benefits far beyond coral reefs – although many see it as beyond our capacity because of the political will it would require. However, it’s still a goal worth pushing if only to counteract the natural tendency of negotiating countries to compromise in adopting a set of emissions cuts that lead to some improvement in our shared future, although without reaching the +2oC goal. (I have a recurring nightmare in which politicians from around the world, dressed in expensive suits, sip Champagne, while congratulating each other on coming together in the spirit of mutual compromise to achieve an historic climate treaty that will keep warming to +3oC. They then all fly home in their private 747s.)

cartoon-un-climate-change-conferenceThis 2011 cartoon might still be relevant in Paris this December. I hope not.
Cartoon ©

While many people, including scientists who do not work on coral reefs, seem to assume that loss of coral reefs is either being exaggerated or does not really concern most of the world, suggestions for more direct action to keep reefs with us are being heard, and some are leading to experimentation and pilot projects. These range from modest to outlandish, and from the sublime to the ridiculous. I fear the outlandishly ridiculous, because I can see us running off and implementing them in a well-meaning, if un-thinking exuberance of effort to just do something quickly. (And if you think I am being alarmist here, take a look at the depth of intellectual capacity being revealed nightly by some of the individuals running for office in leadership roles in Canada, in Australia, in the UK, or particularly in the US, and then ask yourself if calm, rational, long-term thinking will prevail once we recognize we have an existential emergency on our global hands.)

Trump on climate tumblr_nv3d3yVgkE1ql6jblo1_500American politics … these people are competing to lead the world!

I am going to talk about the main solutions being suggested, and then I am going to turn to Dennis Hubbard of Oberlin University for some common sense about what we do and do not know about how coral reefs function. First the main solutions being proposed.

Take care of local impacts

The most modest suggestion, and the one that has been around for about as long as we have recognized the plight of coral reefs, goes as follows:

Focus local effort on managing local reefs responsibly, ensuring fishing is sustainable and not destructive to the fragile reef habitat, ensuring pollution is minimized or avoided altogether, and protecting reefs from the negative effects (such as siltation, burial, flow disruption) of coastal development. This will bring local resources to bear on those human impacts that can be managed locally while ensuring reef ecosystems will be in the strongest possible condition to confront impacts of warming and acidification.

Essentially, this is an argument to take action to improve reef resilience. It rests on some limited evidence that reefs bathed by better quality (less nutrient enriched) water bleach at higher temperatures than reefs nearby in waters that are richer in nutrients due to pollution. This is a useful argument, and one that can be put into practice with modest effort; addressing local problems can also deliver local, obvious signs of improvement in just a few years. A cynic will note that this advice was being delivered around the world long before we noticed effects of warming or acidification, and many coral reefs remain poorly managed – it is not yet clear that reef managers know the best ways of motivating people to curtail overfishing, stop pollution, or avoid inappropriate coastal development (this is true in the richest countries as well as in the more impoverished parts of the world). Still, it is an argument I endorse.

Reef regeneration

A more elaborate set of approaches to saving coral reefs relies on the fact that corals can be vegetatively reproduced by fastening living fragments to the substratum and permitting them to grow into new colonies. This solution involves the establishment of coral nurseries, perhaps the provision of artificial frameworks on which to grow the new colonies, and a program of reseeding to be implemented wherever coral reefs have died, whether due to storm or other physical damage, pollution, coastal development, or bleaching. It its most basic form this approach is almost as low-tech and inexpensive as the simple ‘take care of the local impacts’ argument can be. It provides a ‘useful activity’ for people, and helps preserve hope, while building compliance with management regulations.

coral nurseriesCoral nurseries can be ‘plug on post’ (left, US Virgin Islands) or ‘suspended tree’ (right, Bonaire) systems. Suspension from strings is also possible. Here, the rapidly growing A. cervicornis (staghorn) coral is used. Photos © TNC and © Steve Schnoll respectively.

Naturally, the regeneration approach has been turned into a mini-industry by several entrepreneurs who saw a business opportunity in reef repair. Most prominent of these is probably the non-profit Reef Ball Foundation (with a slew of for-profit subsidiaries) which has focused its efforts on the development of suitable cast concrete reef modules (Reef Balls®) into which are inserted multiple coral ‘plugs’ (relatively large fragments of coral embedded in an epoxy base plug). While these structures do attract fish and invertebrates, they rarely if ever become overgrown with coral, and so remain looking like reef balls rather than regenerated coral reefs. Still they have their uses, and the company offers them for use in a variety of circumstances beyond coral reefs. For the ultimate vanity project the company provides a service (‘Eternal Reefs’) whereby your ashes can be mixed into the cement as the reef ball is being constructed. Mostly people do not talk about the CO2 emissions released in the curing of cement, and they are a vast improvement over old tires, old cars, or old streetcars used as artificial reefs.

A second entrepreneurial approach markets Biorock®, a process for the growing of coral fragments on a wire framework through which is passed a small DC current. The electrical current leads to electrolysis covering the wire surfaces with calcium carbonate and magnesium hydroxide. If the source of power is removed the precipitated minerals dissolve. The privately owned process is licensed to a non-profit, somewhat misleadingly named the Global Coral Reef Alliance, which claims that the electricity also stimulates growth of corals attached to the framework. Most coral reef scientists dispute this claim and there is little support in the peer-reviewed literature, but even if correct, the need for a continuous supply of power limits this approach to small projects close to a power supply. The Biorock approach seems to have been a lot less successful (economically as well as environmentally), and neither Reef Balls nor Biorock offer a real solution to the loss of thousands of hectares of living reef.

A significant problem with both Reef Balls and Biorock technology is that nearby reefs are scavenged for coral fragments to attach to the substrate unless a coral nursery is first established. Other entrepreneurs have focused on the need for nurseries for replenishment, whether or not artificial substrata are to be used. A coral nursery, whether established in shallow protected areas on a reef or in a mariculture facility, permits the propagation of corals from minute fragments, nubbins, containing just a few polyps. Use of small nubbins greatly expands the proliferation possible from a single wild-collected colony. Typically, these nubbins are fastened into epoxy plugs by which they are supported in flowing water. Once grown to a suitable size for out-planting (a few cm across), they are transported to the reef site and the plugs are fastened to the substrate, whether that is a Reef Ball or an area of dead limestone on the reef. Nurseries are mostly being managed simply to grow small coral fragments, frequently as a village project to repair a local reef, but in some cases, they are operated more professionally as cultivation projects for corals showing desired characteristics such as fast growth and tolerance to higher temperatures. Such more ‘professional’ nurseries usually gain some income by supplying tank-grown corals to the marine aquarium trade.

The Australian Institute for Marine Science (AIMS) has recently announced a far more complex research project in which corals will be selected for desirable characteristics and then bred to yield larvae that will then be cultured and tested for tolerance to warm water and/or low pH using their state-of-the-art mariculture facility. The long-term goal is to develop strains of particular coral species that will prove hardier in the reef environment than those naturally occurring there. This project is more correctly termed ‘assisted evolution’ than ‘coral regeneration’. An informative news article about this project and related ones by other scientists is in Nature (and it’s not behind a firewall!).

Setting aside the AIMS project, the major problem with all coral regeneration projects is that they do not address the factors which caused the reef to degrade in the first place. If a reef is being degraded by frequent bleaching events, by low pH, by local pollution, or by a high incidence of coral diseases, cultivating coral fragments and placing them back out on the reef simply provides more coral to be killed. Add to this the fact that managing a coral nursery is a long-term (years), labor-intensive activity, and that transplanting corals back to the reef is similarly labor-intensive, and it is clear that this can only be a solution for repair of local, high importance areas of reef.

Really crazy schemes

In 2012, in a paper in Nature Climate Change, Greg Rau, Liz McLeod and Ove Hoegh-Guldberg, from UC Santa Cruz, TNC Hawaii, and University of Queensland respectively, provided a provocative essay calling for scientists to investigate unconventional solutions to coral bleaching, so that we would have techniques in hand to use in an emergency – e.g. when efforts to reduce CO2 emissions have clearly failed. They gained some ridicule on the web for suggesting that areas of reef might be shaded by floating sails (they were suggesting this as a small-scale, experimental approach to test effectiveness of shading, not as a way of shading thousands of square kilometers of reef). Now, Peter Mumby and others, also from University of Queensland, have suggested that SRM, or solar radiation management, by injection of aerosols into the atmosphere to reduce warming, might have to be considered as an emergency approach of last resort if we really want to save coral reefs.

geoengineering_web_3118327k The TelegraphThis set of geoengineering approaches to climate change headed an article on the topic in The Telegraph. Most are untested and only treat the symptoms rather than actually sequestering carbon.

There are plenty of engineers, geochemists, and others hankering for the opportunity to provide engineering approaches to deal with the symptoms of climate change. After all, humanity has always bent Nature to his will (and the male pronoun seems apt here), so why should we not try to engineer our way out of warming, rather than cut back on our profitable fossil-fuel based economy? Putting aerosols or small reflective particles of some sort up into the atmosphere, to reduce the warming by reducing the amount of sunlight penetrating the atmosphere, has been a favorite approach. There also is evidence that it should work. The massive eruption in 1815 of Mt. Tambora, in Indonesia, pumped enormous quantities of dust into the atmosphere, and 1816 became known as the year without a summer. A much more recent and not much smaller eruption, Mt. Pinatubo in the Philippines in 1991, pumped about 17 megatonnes of SO2 into the atmosphere, resulting in a global cooling of -0.4oC in 1992-3.

There are two huge problems with SRM. First, the cooling is not uniform across the globe, and it is not clear how countries will respond to sudden unfavorable shifts in their monsoon seasons or other ‘bad weather events’ when these have been caused by an enormous geoengineering project done by somebody else (perhaps by someone in a country headed by a Donald Trump type leader with all his diplomatic skills). While research might help us learn how the planet would respond, experiments at scale are hard to imagine. Second, SRM only addresses warming and does nothing to the accumulation of CO2 – ocean acidification would continue unabated and warming would surge if we ever decided to stop putting aerosols upstairs. Come to think of it, it was SO2 pollution, from smelters and power plants that led to acid rain that caused extensive damage to forests and lakes in north-eastern North America and northern Europe in the 1960s, 70s, and 80s; so would SRM solve warming while reintroducing acid rain?

There is a third, political problem which may be even more serious in the short term. Serious discussion of SRM by engineers and scientists could well encourage politicians to believe that we have technical fixes available. They would feel much more free to avoid making difficult commitments to reduce CO2 emissions. I think this is a particularly serious problem because many countries have been viewing the climate conferences as places in which to negotiate to preserve one’s own national interests to the fullest extent possible, and the powerful fossil fuel industry is lobbying hard to minimize and delay any limits on their activities. If the environmental community appears to be suggesting there might be geo-engineering fixes we need to explore, that could shut down the slow forward movement on emissions reduction now taking place.

A Sane Word or Two from Dennis Hubbard

I first met Dennis Hubbard at the long-deceased West Indies Lab, during my first visit to St. Croix and the Caribbean in 1981. I’d describe Dennis as a reef geologist, but like all good reef geologists he thinks a lot about the biology as well. He is now at Oberlin College. He recently posted a comment on NOAA’s coral-list which I thought deserved additional exposure. He was responding to a rambling conversation about what should be done to stem the decline of coral reefs. The conversation had started with comments about bleaching impacts, but had wandered off to talk about crown-of-thorns starfish, Acanthaster planci (because COTS have sometimes become abundant in places where corals are bleached), and lion fish, Pterois volitans (apparently just because they are another predator, although of fish). The crown-of-thorns, or COTS, is a coral predator on Pacific reefs and can cause extensive coral mortality when it is in high abundance. Like most echinoderms, it shows a fondness for population outbreaks from time to time, apparently stimulated by nutrient-rich and/or lower salinity waters during larval life. It has been responsible for about 42% of coral loss on the Great Barrier Reef since 1985.

I have edited Dennis’ words for clarity, but tried to retain his own voice, and I have a couple of comments italicized and inserted in square brackets.  I thank him for letting me play with his words this way.  He begins by referencing the “bounty hunter” approach to conservation – getting rid of a species believed to be causing undesirable changes in an environment:

From Dennis Hubbard:

I have to admit a bit of trepidation with the “bounty hunter” approach to marine conservation. I’m not weighing in on the pros and cons of specific methods for specific species… or the need to control populations that are truly out of control. My concern grows out of having lived long enough, and in enough diverse places, to witness well-meaning but flawed efforts…. and to see the evolution in our thinking over what is “good” and what is “bad”. As a result, my first reaction is always to be wary.

“Some of us remember failed attempts to maintain “the proper balance” between elk and beavers. [I do not know this particular story, although I found this on the situation in Yellowstone. What follows may not be exactly what Dennis meant about the beaver-elk-willow-wolf story.] Beavers use willows for food and to dam streams, but elk also browse on willows. The story goes that there seemed to be too many beavers damming the streams, and not enough elk to hunt. It was believed the beavers were altering the stream environment in ‘bad’ ways, and were so abundant they were depriving elk of food. That wolves and Homo stupidus had killed off all the elk was not discussed, and because killing hunters was frowned upon for reasons I never understood, wolves were the primary target – get rid of the wolves and the elk will return and then deal with the beaver.

“Six years ago, we had a seminar from a young scientist who discussed the problems with beavers modifying the biophysical system (his PhD thesis). The primary drivers were “shown to be” loss of elk and those damming beavers.

“He just came back last year to give another talk….. and apparently the entire situation has changed. The elk are coming back in droves after stringent conservation efforts, but the biophysical system is not resetting. The suggestion is that the system had reached a “tipping point” beyond where the fluvial system could reset…. or at least that’s what they are thinking now. The working alternative is that maybe the beavers they drove out to stabilize the system weren’t actually the problem they had thought… and that the elk-flora connection wasn’t as simple as assumed – nor the link to the wolves. These working hypotheses are pretty different from the standpoint of implementing a management plan…. maybe it’s beavers… maybe it’s elk…. both?….. neither?… how about those wolves? The hypothesis they have now is too complicated to lay out here, but suffice it to say that it’s pretty different from what they thought less than a decade ago. So… now we have no beavers, no wolves, a moderate increase in elk…. and no measurable improvement in the system!

“I also lived through a program in northern Maine where they systematically went after coyotes that were apparently driving down the deer population…. a huge source of revenue. Forty years later, there are neither coyotes nor deer. And, in those few places where deer are abundant, we hear complaints that “there are more deer than when Columbus landed” and that the conflict between growing populations of deer and farmers is due to the deer side of the equation. I don’t claim to be an expert on the latter balance, but I have read descriptions of Benedict Arnold having no problem shooting a couple of deer a day to keep his soldiers well fed en route to Montreal. Today, hunting is pretty dismal along that route. Maybe Benedict shot straighter than average hunters today with their semi-automatic rifles. But, maybe not.

“Same story for porcupines. In the early 1960s, we had a hefty bounty on them, largely because of their drive to find salt…. which attracted them to the handles of shovels, axes, etc. all valued by any good Mainer. I could go on, but I’m sure everyone gets the pattern.

“So….. let’s move on to the present marine system. I’m certainly not arguing that COTS are “great” for reefs or that invasive Lionfish are “good” for other Caribbean fauna. However, I have even read about efforts to extirpate damselfish, in some instances characterizing them as the most negative impact on coral reefs today. While I agree that, pound for pound, they are the most dangerous beast on the reef, I remember a time when their “farming” methods were heralded as somewhere between “efficient” and “necessary for the maintenance of healthy algal turfs”. [For those who don’t know, there is a group of usually drab but robust and aggressive damselfish species that are territorial herbivores (most damselfish feed mostly on plankton), and that defend and even cultivate their algal gardens.]

“As I understand the situation, in some places, damselfish are nipping off “too many” polyps to create algal habitat and are, therefore, perceived as a source of local “reef decline”. I was in Belize last summer with the Keck Geology Consortium and watched a student (not mine) do a great study that looked at where damsels did and did not “damage” substrate. It turned out that they nipped away somewhat equally in areas of Acropora cervicornis (staghorn coral) that were “healthy” and “not so healthy”, but negative effects were only occurring in areas that were already degraded. If this is the case, then killing the fish won’t have much of a positive effect (they seem to only affect corals already on their way out)…. and fish biomass is going to be lower. While this is only one example from one place, the apparent assumption where damsels have a bounty on their heads must be that substrate loss trumps higher fish biomass, so the damsels have to go.

Dusky_gregory_Stegastes_nigricans_(5834901444) Paul AsmanStegastes nigricans is an Indo-Pacific representative of the guild of territorial damselfishes that cultivate algal gardens (clearly visible on the inner branches of the coral behind the fish). Photo © Paul Asman and Jill Lenoble.

“There has been a long-standing argument about the value in restoring/protecting parrotfish as a mechanism to prevent reef corals being out-competed by algae. A recent article in Coral Reefs fairly clearly shows that a significant rebound in grazing fish abundances in protected sites in the Florida Keys has had no measurable impact on coral cover [L.T. Toth and others, 2014]. We saw similar patterns in the Virgin Islands in a study that compared coral cover, macroalgal density, and grazers on two reefs 2 km apart – one in Buck Island National Park and the other on Tague Bay, where years of data were available from when West Indies Lab was still there.

“The long and short of it was that parrotfish numbers were up significantly in the park for obvious reasons – they were not being fished. At the same time, urchin densities along the Tague Bay forereef were much higher that two decades earlier and, in some places, were close to what had been reported prior to 1983 when the spiny sea urchin, Diadema antillarum, almost went extinct across the Caribbean because of some highly contagious disease. At both sites because parrotfishes and urchins are both herbivores, macroalgae were essentially non-existent…. but, so were new juvenile corals. The apparent issue was a failure in coral recruitment, but the question is how much of this was caused by climate change versus changing nutrient dynamics versus warming/acidification – each having different management implications.

“Whatever the explanation, both sites have higher rates of bioerosion today than they did when grazers were scarce because parrot fishes and urchins rasp away at the substratum while feeding on algal turfs. Because, coral cover has remained low in both instances, the balance between carbonate production and bioerosion is going progressively in favor of the latter…. not due to losses of corals, but rather due to increased bioerosion in an area that is not recovering with respect to calcification. From a purely biological perspective, it might be argued that this is all good news because at least fish biomass is going up. But, this seems contrary to the argument in favor of hunting aggressive damselfish cited above….. to paraphrase it as I understand it, “higher fish biomass is not a good thing in light of all the negative impacts their nipping at corals cause”. So, at what point do we start hunting the parrotfish and urchins to cut back on their bioerosive action?

“I am confident that there are people on coral-list closer to some of these examples that I am… and I will defer to their opinions. My larger point is that, even if particular examples are off base, there have been more than enough examples of conservation gone awry because we “managed” a population based on our usually over-simple perceptions of “good” and “bad” at the time. I often wonder whether the greater hubris exists in our earlier perception that the world was “our garden” or in our present sense that we can always “fix it”. As we discuss the pros and cons of different strategies, we want to be very careful about assumptions that are too often based as much on our personal values as on irrefutable data.

“As we look toward species of coral that might be more resistant to warming, we might ask whether they are “equivalent” to what was there before (recovery vs restoration)? Certainly there is a tremendous potential for loss. Do the “better” [more warming resistant, faster growing, more easily cultivated] corals produce carbonate at similar rates and create skeletons that are similarly robust to what occurred on reefs in past years? Putting branching corals [which are favored in many nursery/restoration projects because they grow quickly to rapidly provide coral cover] at sites previously dominated by massive species is going to change the resistance of that community to increasing wave action as climate-change induced storminess is on the rise. And… if corals are broken more often, they will be moved more easily by those same waves. In this example faster-growing corals that are more easily broken could lead to reduced accretion and less reef building. So, creating coral cover quickly might be at odds with reef building unless we are very clever.

“Changing gears, if the solution for reef islands confronted by sea level rise is “more sand”, might actions to increase bioerosion on the surrounding reef be “better”? A total budget approach says “no”, and I agree, but I have seen the opposing view expressed [on coral-list]. In addition, to the extent that bioerosion is contributing to a loss of surface rugosity, it is lowering the potential for wave reduction. So…. should we be killing grazers in areas where coral cover is already low so that we can slow down large-scale reef erosion. Absurd… maybe, but…?

“I am advocating for none of these alternatives, but am concerned that we are not thinking about them and others in a systematic manner. Some of the suggestions I have made seem as bizarre to me as they probably do to the readers. However, what we presently know about the complex predator/prey relationships obviously seemed equally far-fetched to the managers who took paths in the past that we now know to be nonsense. We have backed ourselves into a corner and dragged the reefs in with us. Perhaps we don’t have time for rational thought, given the brief interval between the creation of “knowledge” and the implementation of “policy” based on it.

“I hope that the upcoming meeting in Hawaii [the 13th International Coral Reef Symposium convenes in Honolulu in June 2016] will give us the opportunity to have meaningful discussions on this topic. These can only occur across disciplinary boundaries, but I fear that, much as we have done at past conferences, we are each going to spend most of our time in [our own particular disciplinary silo, listening to talks, viewing posters and participating in workshops within our specialist fields] because “it’s what we do”. I hope we can all discuss this further, but you’ll have to catch me as I run from the biology session to the geology session and then over to hear all about management. There’s way too much to learn that won’t be discussed in “my favorite” session”.

Back to me, again – I think Dennis provides a useful word of caution, and calls on all of us to be a little more humble as we advance our favorite causal explanations for the events we see unfolding on coral reefs and elsewhere in this world. Things are seldom quite as simple as they first seem.

An Innovative Approach Worth Pursuing

A coral breeding program, such as the one now being undertaken at AIMS, using the state-of-art National Sea Simulator, is a long-term, high-tech operation, requiring a substantial investment in mariculture infrastructure and skills along with skills in genomics, agricultural genetics, coral and algal physiology, genetics, and developmental biology. However, it has the potential capacity to achieve significantly enhanced resistance to warming and acidification in a much shorter time than evolution would take unassisted. Drs. Madeleine van Oppen of AIMS, and Ruth Gates of University of Hawaii lead teams that have been collaborating on investigations into the capacities of corals to tolerate warm water for several years. It has been known for some time that corals of the same species, but living in different geographic regions have different tolerances to warming. Most notably, corals that survive the very harsh warmth of the Persian Gulf tolerate substantially higher temperatures than do those same species in the Indian Ocean. One breakthrough was the discovery that some corals possess genes conveying greater tolerance that can be ‘turned on’ by experiencing a bout of warmer temperatures. This may mean that corals which have already experienced warm water, and bleached, in the recent past may now be capable of withstanding still warmer water successfully. Another early breakthrough was the discovery that different genetic strains of their symbiotic algae seemed to convey different degrees of warmth tolerance to the coral host. Most recently van Oppen’s team has shown that Acropora millipora coral from the northern Great Barrier Reef tolerate warmer temperatures than do colonies of this species from the southern Great Barrier Reef, and that crossing the two strains produced offspring that inherited the mother’s temperature tolerances. (Perhaps it should not be surprising to discover that the genetics of temperature tolerance in a coral – really in a symbiosis between a coral and its single-celled algae – was going to be complicated, but it is encouraging to see how much progress is being made.)

BIF_Oct13_SeaSim-631x356The National Sea Simulator in Townsville, Australia, is a high-tech, climate-controlled building providing aquaculture facilities that can be precisely controlled for a broad suite of environmental factors – temperature, light, CO2, pH, and so on.

The challenge now being faced is whether by selecting for specific algal strains, by pre-stressing corals to ‘turn on’ their temperature defenses, by cross-breeding corals with different tolerances, or by a combination of these and other new techniques, it will be possible to raise coral strains with superior tolerances to temperature. Doing the same for pH would also be useful. Then will come the challenge of generating sufficient numbers to be able to out-plant them to reefs facing temperature and pH stress. Assisted evolution like assisted migration (where plants are helped to extend their ranges to keep pace with climate change) is a novel approach to management that moves environmental management from the “stop people doing bad things” mode to a more pro-active “help natural systems do the right thing” mode. It’s a new world we are creating, and new approaches to environmental management will likely be required. In picking the approaches to use, let’s not be simplistic and do something really stupid to the only planet we have.

Saving Coral Reefs

I think the science being done by van Oppen and Gates and some other coral biologists at labs around the world is definitely worth doing given the perilous situation we have created for reefs, but I also recognize the immense field effort that would be required to fully warmth-proof coral reefs around the world by out-planting more resistant strains of coral species. We also need to collect as much information as possible on the effects of this year’s el Niño to characterize the temperatures experienced, the extent of bleaching, and the extent of mortality at a broad range of sites. Scientists from the Reef Check monitoring program are attempting to ramp up a monitoring effort right now to do that, and two posts on coral-list today (one by Gregor Hodgson, Director of Reef Check, and the other by Jim Hendee, NOAA) provide updated information and a plea to scientists and managers to report observations of bleaching to the list). Will corals this year prove more resistant to warm temperatures than they were in 2010, or in 1998? If they are, that would be encouraging news. And is NOAA’s estimate of 6% mortality due to bleaching during 2014-2016 accurate.

We also need to continue to work to improve the management of local stressors like over-fishing and pollution on coral reefs. This has been a critical need for a long time, but it becomes more critical every year as climate-related stresses increase. And those of us in western, developed countries need to remember that most coral reefs are used for far more important things than the entertainment of tourists. Reefs are economically and culturally important in most parts of the world where they occur, and calm contemplation of their pending disappearance is simply not an ethically acceptable attitude.

Far better, of course, to bring CO2 emissions under control as quickly as possible.

5 thoughts on “The Mega el Niño – How to Protect Our Coral Reefs (Part 2)”

  1. Peter, This is an excellent summary of the situation—especially concerning parrot fish. As you know I have been photographing the same plots annually in the Florida Keys for 55 years. In recent years I have been observing the increase in parrot fish and how they are nibbling away the reef substrate. Yes they are protected in so-called SPAS. The substrate is of course corals that have died since I began my serial photography in 1960. It would be very difficult for coral larvae to become established because they are nibbled away with the algae the parrot fish are after. As you know I am still convinced that microbes and toxic metals and pesticides in African dust was and remains the cause of demise in the Florida Keys. Death of corals peaked throughout the Caribbean in 1983, along with Diadema. That year saw the highest peak of African dust flux into the Caribbean during the 50 years that dust flux has been monitored. Like bleaching and coral diseases there is little we can do in the short term. It will be many years before greenhouse gasses return to 1950s levels.

    1. Gene,
      Direct observation over time, as you have done, is the best kind of information on long-term trends. I don’t doubt what you say about parrotfish and how their grazing of dead coral/bare limestone precludes coral larval settlement. The full parrotfish story is likely complex in several ways, one of which is that their grazing, which removes some coral creating small patches of bare limestone, can be helpful to coral recruitment on a healthy reef, particularly because they are also removing algae, but once a reef gets sufficiently denuded of coral (for whatever reason) the parrotfish grazing just helps keep the now large areas of bare limestone free of new recruits and juvenile corals. Main point I wanted to make is that we too often think there will be a simple, one-size-fits-all cause of coral loss on reefs around the world. Life has never been that simple.


  2. Thanks for this insightful assessment. Let’s hope that we reject the ideologues and muster the political will (in time) to head off the impending catastrophe. In any event, we need to keep trying. By the way, I have great respect for many of those proposing what may be seen as crazy schemes to offset the demise of coral reefs. They may not have all the answers, but their proposals may well reflect a level of desperation that many of us are feeling as we observe the continuing depredation.

  3. Hi Peter

    I worry that policy-makers and managers will use the idea of “super corals” the same way that they used the idea of “resilience,” to let themselves off the hook. They think, “scientists will research our way through these perilous times (love your use of the word perilous) to save coral reefs.” I saw this precise response at the US Coral Reef Task Force years ago, when there was a presentation about reef resiliency. Resiliency is taken to mean that we (managers and policy-makers) don’t have to address the proximal causes of decline. That said, I give managers and politicians a lot of credit for addressing many local problems. It’s at the regional and global scales that we fail, and that’s where the potential for super corals and the concept of resilience provide cover to politicians. Should both of these topics be actively researched? Yes, but not with the promise that either will save our reefs. That’s clearly a promise we can’t keep. Instead, results should inform management and society about what we are losing, the capacity of reefs to thrive or die under predicted conditions this century, and how all of this plays out in terms of restoration. I agree with you that restoration has value, but limited to high value reefs at restricted spatial scales. I think restoration efforts are especially well-suited when they target select species, such as engineering the recovery of staghorn and elkhorm corals (and I spend time trying to make this happen). The idea of restoring coral reef ecosystems, however, is an impossible task. That’s why the idea of super corals is misleading, too. Anyway, before a start to ramble too much, I applaud your efforts to try and explain all of this in nontraditional formats. Best regards, Steven PS: I think that the coral list-server have devolved in its usefulness. It could use some editing to avoid excessive dumbness that shows up too frequently. Just my opinion. And I get that everyone is allowed to have their own opinions, even when they are wrong.

    1. Hi Steven,
      Wow, its been a very long time since we have seen each other.
      I agree fully with your comment, especially the bit about policy-makers seeing new research on ‘super’ corals as an excuse to not take any extra measures to sustain coral reefs — the science/technology will save the day. On a wider canvas, I am convinced the global climate negotiations have languished so badly because the negotiators have entered into the process with the perspective that they must, first and foremost, guard their own country’s self-interest, rather than look for ways to quickly protect the planet’s interests. I think we (scientists, managers, engineers) should regularly remind ourselves that Biosphere 2 was a dismal failure as first conceived — we clearly did not know as much as we thought we knew about how to design a functioning, self-sustaining biosphere. Humility can be good.

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