Report: Coral reefs dying off

Pollution, overfishing and climate change have severely damaged one-third of the world's coral reefs and could destroy another third in the next 30 years, scientists warned Thursday.

"There are no pristine reefs left," the researchers reported in the journal Science. They predicted that without "radical changes" in efforts to save the world's reefs, "close to 60 percent of them could be lost by 2030."

The report -- based on hundreds of historical documents, fishing records and scientific studies using sources as diverse as early ship's logs to modern environmental surveys -- is the most comprehensive assessment of coral reef health ever made. It also is the most dire.

"There is very grave concern that the reefs are going to get through this," said John Pandolfi, of the Smithsonian Institution, one of dozens of research organizations participating in the studies.

The research covers 14 major reef systems in all of the world's oceans, but the situation may be most urgent in the Caribbean, where a massive, regionwide decline has reduced the coral cover of reefs by 80 percent over the last 30 years. Researchers say Caribbean coral losses are so severe that the reefs' ability to recover may be "irretrievably damaged."

"In regions where the process is most advanced, such as Jamaica, the corals are either dead or dying, the fish are tiny, few other organisms exist and the formerly vibrant reef structure is coated with algae," said University of Florida zoologist Karen Bjorndal.

"The Great Barrier Reef of Australia is said to be largely pristine, but it's actually a third of the way toward ecological extinction," she said.

In reviewing reports on coral reef health that go back hundreds of years, the more than 30 researchers involved in the assessment say it is clear that human activity -- shipping, fishing and dredging -- has always had detrimental effects on the world's reefs.

"Humans have never been innate conservationists," said Richard Cooke, archaeologist at the Smithsonian's Tropical Research Institute in Panama. "But a point of no return now looms so large for coral reefs that only draconian measures against human exploitation will ensure the survival of these fragile ecosystems into the next decade."

In recent decades, human impact has accelerated through increased commercial fishing, coral collecting, chemical pollution, urban runoff and recreational activities. Sometimes the human role in reef destruction is hard to trace.

In a separate report Thursday, scientists linked the mysterious decline of corals in Indonesia's Mentawai Islands in 1997 to massive wildfires that ravaged the region's tropical forests that year. Soot from the fires triggered a red tide outbreak, which in turn, suffocated the reefs.

Until recently, human impact has tended to be local or regional in scope. But Pandolfi said global events -- climate change and worldwide increases in greenhouse gases -- are now accelerating the loss of reefs. The cumulative effects -- loss of habitat for fish, disrupted food chains and loss of biological diversity -- have been devastating, he said.

"It's a little like what happens when someone who is already sick gets the flu," he said. "A healthy person might be in bed for a few days and then recover. A person who is already sick is more likely to die."

Scientists say the evidence that climate change is now contributing to coral reef die-offs is "incontrovertible." Tropical corals live for most of their lives in waters that are only a few degrees below levels that are lethal. Prolonged increases in ocean temperatures push them over the edge. Average global temperatures have been increasing gradually for the last 30 years, but the slow upward trend is punctuated by regional heat waves that can have more dramatic effects.

In the face of such pressures, scientists warn that "local successes in protecting coral reefs over the past 30 years have failed to reverse regional declines." Although reefs grow slowly, some will probably adapt to changing conditions. But comprehensive protection measures will be needed to keep many of them alive, the scientists said.

The United States and Australia have led the way in creating coral reef preserves where fishing, dredging and other harmful activities are prohibited. But even those countries have set aside only about 5 percent of the reef area that needs to be protected, Pandolfi said.

Many reefs, like those off both coasts of Central America, overlap national boundaries and will require multinational efforts to protect them, he said. "We are going to need a massive increase in international cooperation to have any chance of turning this around," he added.

You know, I developed an aversion to touching things after coming into contact with fire coral once and having been nipped by an eel on another occasion. Plus, scorpion and stone fish look so much like the surrounding coral you never know what you're going to touch if you don't inspect very closely first.

Oddly enough, underwater photography has made me a beter diver. I'm more patient and less self concious underwater. When I was still a novice, I was always overly aware of the mechanics of my diving and it tended to take a lot of air out of my tank as a result. After I became more preoccupied with my camera and looking for the little details, I became much more relaxed underwater and learned a lot more quickly to get my buoyancy right because that enhances your photography abillity. I have also learned to really enjoy the little things on the reef. So many creatures are there but many are very tiny. It takes patience and the abililty to hover in one spot to truly appreciate them.

I like a nice slow drift dive myself. I like to have my octopus and gauge in close to my body because that makes you more streamlined. In a sense, SCUBA is the closest the average person can get to being an astronaut and visiting alien worlds. Total weightlessness- it's like flying in some senses. I really enjoy it and whatever I can do to get an extra couple of minutes out of a dive (relaxation, streamlining, not diving deeper than need be) are things I strive for. It pays off. If you're patient, you can slip right up on a turtle or a sleeping shark or a stingray without agitating it and get a choice view (and photo) of it.

While I agree that coral reefs are under stress, particularly from fishing practices, I have my problems with the tone of this report. First, coral reefs go through periodic dieoffs under natural conditions, some of which are far more devastating than anything precipitated by humans. Second, I doubt that they can even define what constitutes "pristine." Third, by what criteria are these assessments of risk made? I seriously doubt that we know so much about the function and behavior of coral reefs to be making such blanket statements.

There are some fairly obvious problems, the most important of which is excess nutrients in the waters where coral reefs are found. The source of these excess nutrients is from inadequate sewage and agricultural runoff, primarily. Some areas also have increasing turbidity due to increased erosion of coastal sediments. There's no doubt that coral needs clear and low-nutrient water to "prosper". Would you dispute that nutrient concentrations and turbidity have increased in many coastal regions? I sure hope not. In my reply to another poster in this thread, I also linked to an excellent article that tied white-band disease in the Keys, responsible for nearly eradicating elkhorn coral, to human waste. Is that a "natural" die-off?

It stinks of politics. Can you tell me who funded this research?

Apparently there was a variety of funding sources, based on the variety of author affiliations:

Department of Paleobiology, MRC-121, National Museum of Natural History, Post Office Box 37012, Smithsonian Institution, Washington, DC 20013–7012, USA.

Centre for Resource and Environmental Studies, Australian National University, Canberra, ACT 0200, Australia.

Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, La Jolla, CA 92093, USA.

Centre for Coral Reef Biodiversity, School of Marine Biology, James Cook University, Townsville, QLD 4811, Australia.

Archie Carr Center for Sea Turtle Research, Department of Zoology, Post Office Box 118525, University of Florida, Gainesville, FL 32611, USA.

Center for Tropical Paleoecology and Archaeology, Smithsonian Tropical Research Institute, Box 2072, Balboa, Republic of Panama.

California Sea Grant, University of California Cooperative Extension, Santa Barbara, CA 93105, USA.

Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA.

Sea Grant is NOAA; I'd suspect CSIRO for the Australian authors, and the usual suspects (NSF) for the American academic sites; obviously the Smithsonian gets its funding from the U.S. government.

In my previous reply, I asked "Is that a "natural" die-off?" Re-reading, I realized that I misinterpreted what you were saying, and the question was not properly phrased. I should have asked "Is this loss of elkhorn coral as devastating as a natural die-off?"

Follow-up question: when you say that "coral reefs go through periodic dieoffs under natural conditions", what are the natural causes of those dieoffs? I can think of a couple, but I'd like to know what you're thinking of.

By the way, here's the abstract of the Science paper:

"Degradation of coral reef ecosystems began centuries ago, but there is no global summary of the magnitude of change. We compiled records, extending back thousands of years, of the status and trends of seven major guilds of carnivores, herbivores, and architectural species from 14 regions. Large animals declined before small animals and architectural species, and Atlantic reefs declined before reefs in the Red Sea and Australia, but the trajectories of decline were markedly similar worldwide. All reefs were substantially degraded long before outbreaks of coral disease and bleaching. Regardless of these new threats, reefs will not survive without immediate protection from human exploitation over large spatial scales."

Here's how they define "pristine":

"Detailed historical record of marine resource lacks any evidence of human use or damage"

It appears to be a pretty good paper. You ought to try and get it.

Source: University Of Florida
Date: 2003-08-18

Coral Reefs' Decline Actually Began Centuries Ago, New Research Shows

GAINESVILLE, Fla. --- Global warming and pollution are among the modern-day threats commonly blamed for decline of coral reefs, but new research shows the downfall of those resplendent and diverse signatures of tropical oceans actually may have begun centuries ago.

According to a paper set to appear Friday (8/15) in the journal Science, the downward spiral started when people first began killing off reef-frequenting large fish, turtles, seals and other top predators or herbivores – a process that started thousands of years ago in some parts of the world and just a century or so ago in others.

"What really struck us was the universality of the decline trajectories," said Karen Bjorndal, one of 12 authors on the paper and zoology professor and director of the Archie Carr Center for Sea Turtle Research at the University of Florida. "It didn't matter if we were looking at the Red Sea, Australia or the Caribbean. As soon as human exploitation began, whether in the 1600s in Bermuda or tens of thousands of years ago in the Red Sea, the same scenarios were put into play."

The project is an outgrowth of research published in 2001 that tied overfishing to worldwide declines of coastal ecosystems. That paper argued that overfishing disturbs the ecological balance of marine environments, with the killing of green sea turtles, for example, ultimately contributing to the die-off of sea grasses. The authors of the current paper, who were among the scientists involved in that research, zeroed in on coral reefs, long seen as seriously threatened by modern pollution, global warming and diseases that cause the coral organism to die and "bleach," its mosaic of colors turning a uniform skeletal white. The goal: reconstruct the ecological history of the reefs from before the first people appeared to fish them some 40,000 years ago to the present era.

The scientists pored over historical and archaeological records surrounding major reef systems in 14 regions in the Atlantic and Pacific oceans and the Red Sea, including the reefs of the Caribbean and the Great Barrier Reef. Each scientist handled a different region, with Bjorndal tackling the Bahamas and the Cayman Islands. She said her research led her to more than 400 references for the Bahamas alone, including papers on archaeological findings and colonial fishing-catch records. Among her sources: research by UF anthropologists showing that indigenous Bahamians hunted green turtles to such an extent they seriously depleted the herbivore long before the first colonists arrived.

"I used to think that green turtles were basically in pristine shape when Columbus arrived, and I don't think that anymore," she said.

The researchers discovered that all the reefs experienced declines as a result of human activity, although the declines occurred over different periods of time and were more advanced in some places than others. Regardless of geography, the researchers learned, the declines follow the same pattern. First, people deplete large predators such as sharks and large herbivores, which tend to be both easy to kill or capture and slow to rebuild their populations. Next to go are smaller animals, such as small fishes, followed last by sea grasses, corals and other so-called "architectural" parts of the coral reefs.

By 1900 -- decades before the first scuba divers experienced the splendor of coral reefs -- this slow death had already started in more than 80 percent of the reefs worldwide, the scientists found. Today, in the regions where the process is most advanced, such as Jamaica, the corals are either dead or dying, the fish are tiny, few other organisms such as shellfish exist, and the formerly vibrant reef structure is dull and coated with algae. The Great Barrier Reef sometimes is said to be largely pristine, but it's actually as much as a third of the way toward ecological extinction, Bjorndal said.

For the first time, Bjorndal said, the research will give managers of the world's coral reefs – and the countries that have jurisdiction over these resources -- a yardstick they can use to determine how far their particular reef system has progressed along the ecological "extinction continuum." She and the other scientists hope the result will help spur strengthened conservation efforts. She noted that, with the exception of the extinct Caribbean monk seal and a handful of other top predators, most reef organisms have been depleted but are not yet extinct – offering at least some hope for the future.

"If we could step back in with strong management decisions we could restore the ecosystem, but that's a matter of political will and funding and a lot of other influences that are difficult to predict," she said.

For European lakes, how clean is clean enough?

Sid Perkins

From Reno, Nevada, at a meeting of the International Union for Quaternary Research

Decreases in water quality are often associated with modern farming practices, including the use of artificial fertilizers and the practice of keeping many animals in small areas. However, new research on lakes in Denmark suggests that agriculture has been affecting water quality there for more than 5,000 years.

SØ POLLUTED? Sediments from Dallund Sø suggest that the Danish lake has been severely tainted by agriculture for more than a millennium.
J.K. Winter

The finding could help determine the background levels of various water pollutants. That's important because the European Union is now developing lake-water quality standards that will be implemented by 2015, says Emily G. Bradshaw, a paleoecologist at the Geological Survey of Denmark and Greenland in Copenhagen.

Bradshaw and her colleagues looked at sediments from Dallund Sø, a 12-hectare lake in central Denmark. That area has been one of the most densely populated and intensively cultivated regions of Europe for at least 6 millennia, says Bradshaw.

The rate of sedimentation in Dallund Sø increased dramatically about 1,000 years ago, a date that roughly corresponds with the founding of a town nearby and a significant change in agricultural practices throughout Denmark. Another spurt in silt accumulation around 2,500 years ago matches a period of rapid deforestation by area settlers. The team's analyses suggest some deforestation also occurred around the lake as many as 6,000 years ago.

Even though modern agricultural practices have caused plant-nutrient concentrations in Dallund Sø to skyrocket, the researchers discovered that the lake has been extremely nutrient-rich for the past millennium. Many algae-nourishing substances probably entered the lake via an ancient agricultural practice known as retting. In this procedure, farmers submerged bundles of hemp and flax in the lake during the winter so that the plants would soften and partially decompose, easing the recovery of fiber from the stalks.

A significant boost in zooplankton and aquatic plants in sediments deposited just after the rapid deforestation 2,500 years ago suggests that the nutrient concentrations in the lake jumped considerably at that time. Chemical analyses of sediments deposited immediately after the deforestation hint that each liter of lake water then contained about 50 micrograms of phosphorus, more than twice the amount the water contained only a century before. Today, the lake's phosphorus content varies between 65 and 120 µg/l.

Bradshaw says that the earlier concentrations shouldn't be used as thresholds for the proposed European water standards because the only way to meet those targets would be to depopulate the region.

The source of these excess nutrients is from inadequate sewage and agricultural runoff, primarily.

Given that cities used to dump raw sewerage into rivers and bays, I would not be persuaded that ag runoff is the cause without significant amounts of data.

Some areas also have increasing turbidity due to increased erosion of coastal sediments.

Here again, what were the background measurements upon which these claims are founded? Is it really worse now than for example in the 60's when dredging in bays and dumping operations at sea without any environmental review or mitigation were commonplace? How about the oil spills and maritime dumping that were then more frequent?

Im my study of nitrates in the San Lorenzo watershed, I found that the quality of such measurements that started in the 50's were horrible until about 1985 when the County bought more accurate equipment. Even now their measurements are subject to gross, single sided errors. That's a river in a populated area. Now, consider our measurements in the oceans. Do you really think that they had a good temporal and spatial picture back then of nutrient levels that accounted for seasonal variations and singularities (floods and hurricanes) from which to construct a baseline? I honestly doubt it.

Would you dispute that nutrient concentrations and turbidity have increased in many coastal regions?

I don't know for a fact, but from what I've seen of the West Coast, nutrient levels appear to me to have gradually fallen until very recently. In the last decade or so the recolonization of the coast to the point of overpopulation by seals and sea lions has led to a big jump in both nitrate and fecal coliform levels, especially south of Ano Nuevo.

I also linked to an excellent article that tied white-band disease in the Keys, responsible for nearly eradicating elkhorn coral, to human waste.

I'd have to read it. It sounds plausible at first, but I've seen so many frauds in this kind of work as to be more skeptical, particularly when it comes to attribution of causes. An example is the afore mentioned nitrate pollution from pinnipeds. The authorities assume that that contribution constitutes "natural" while anything over and above that is "pollution" simply because of their bias. They NEVER question whether the animals are getting overpopulated, even though there are few natural controls on their population (shark numbers are down and grizzlies are decidedly unpopular on public beaches). The harbor seals are floating up on the beaches from contagion.

I'd like to know how these scientists have determined the relative mass balance contribution of nutrient from all sources, especially considering how the system consumes that nutrient in rates that vary by history of location, temperature, predation, and seasonal disturbances. The work I've seen on that front so far looks pretty sketchy.

In response to another of your comments, both temperature and sea level changes have accounted for historic coral die-offs. I don't know about the impact of hurricanes.

Given that cities used to dump raw sewerage into rivers and bays, I would not be persuaded that ag runoff is the cause without significant amounts of data.

Remember that we're talking about coral reefs, not every place on every coast. There are some areas (such as the Phillipines) where agricultural runoff with more fertilizer would have an impact on coral reefs; in most cases, the problem is untreated or poorly-treated sewage from the increasing population in island countries. The article about the Keys suggests input from the proliferation of septic tanks as the Keys population has increased.

There are actually three papers in Science (August 15) that discuss coral reefs. The article about the Caribbean corals is perhaps the most indicative of the ecological/environmental trends and causes. This is a good part of the article; you'd have to track down the references:

"Recent paleoecological work suggests that this pattern of decline in many areas of the Caribbean is unprecedented within the past few millennia (22, 23). There is no convincing evidence yet that global stressors [e.g., temperature-induced bleaching and reduced rates of carbonation via enhanced levels of atmospheric CO2 (24)] are responsible for the overall pattern of these recent coral declines. More likely, local factors originating both naturally (e.g., disease, storms, temperature stress, predation) and anthropogenically [e.g., overfishing, sedimentation, eutrophication, habitat destruction (14, 25, 26)] are occurring at Caribbean-wide scales." Science references don't provide paper titles.

The article discusses observations of what's happening and cites possible causes. Eutrophication has been a comomon theme in a lot of papers about coral reef decline. Coral reefs need clear water; that's obvious. Whether or not they have a baseline of water quality measurements is not as vital as documenting that the coral reef is declining, because a healthy coral reef exists in clear water. Some of the causes of eutrophication are related to other effects, like white-band disease. Compound effects are probably going to be significant.

In the last decade or so the recolonization of the coast to the point of overpopulation by seals and sea lions has led to a big jump in both nitrate and fecal coliform levels, especially south of Ano Nuevo.

This doesn't appear to be a problem for most of the reefs; the articles note that the loss of top predators and overfishing were one of the first human effects (and occurring before "historical" documentation). There haven't been any new top predators or species in most areas.

In response to another of your comments, both temperature and sea level changes have accounted for historic coral die-offs. I don't know about the impact of hurricanes.

I was hoping you'd include sea level. It's doubtful that we're going to have a major sea level decline anytime soon (and that would indeed contribute to a natural coral die-off!)

I would like to add something here on a personal note.

I would love nothing more than to read a technical paper on this general range of topics and be able to accept the conclusions on face value. Unfortunately, I have been burned so many times by bad measurements, faulty reasoning, wishful thinking, political editing, and outright fraud that I can no longer take a position as easily as you or any other rational conservationist might desire when the asset at issue is very possibly in immediate danger.

The politicization of a fraction of scientific work has, in that respect, discounted the value of all scientific inquiry. It sucks. It keeps me from taking a position when I would emotionally and rationally otherwise wish to do so. I'm truly sorry for my continued skepticism, but it's been earned, and I remain, if anything, still too credulous.

I hope you understand that.

There is a real value in speculative reasoning. The process posits the potential for an understandable hypothesis, but that doesn't mean that we have a theory upon which to base policy. Still, if some action seems to be advised, how do we determine what is enough, who should take it, and who should pay?

This is where a system that trades in pooled risk discounted for uncertainty has real potential compared to centralized planning based upon an idiotic gambit such as the precautionary principle (which has never been subjected to its own test). I wish I had time to explain that to you further (the concrete truck is leaving now and I have yet to float it). Talking about the economic possibilities here without your having read that monster is similar to having a discussion about the nitrate cycle with someone who has never taken biology.

I would love nothing more than to read a technical paper on this general range of topics and be able to accept the conclusions on face value. Unfortunately, I have been burned so many times by bad measurements, faulty reasoning, wishful thinking, political editing, and outright fraud that I can no longer take a position as easily as you or any other rational conservationist might desire when the asset at issue is very possibly in immediate danger.

The politicization of a fraction of scientific work has, in that respect, discounted the value of all scientific inquiry. It sucks. It keeps me from taking a position when I would emotionally and rationally otherwise wish to do so. I'm truly sorry for my continued skepticism, but it's been earned, and I remain, if anything, still too credulous.

I hope you understand that.

I do. It's worth having that skeptical attitude. Though my sentiments lie with the environment, I try to have a scientific attitude toward reported research. I don't like "scare stories". However, I have a considerable base of knowledge that has created an awareness of environmental concerns. This report, and the one regarding the depletion of large pelagic predatory fish, are completely congruent with my base of knowledge. The causes of the degradation of the reefs and the intense depletion of fisheries resources are multifarious, BUT I know, with an accompanying sick sensation in my stomach, that these reports are real and that the situation is (to be blunt and simple) not good. And not easily rectified. [The tone that some of the scientists take when discussing their results is somewhat similar. They express reasons for hope, but they emphasize that if significant action is not taken soon, hope may be rapidly extinguished.]

Given all that, do you have access to Science magazine? Can you read the papers? I'd rather not post full text to FR.

There is a real value in speculative reasoning. The process posits the potential for an understandable hypothesis, but that doesn't mean that we have a theory upon which to base policy. Still, if some action seems to be advised, how do we determine what is enough, who should take it, and who should pay?

I wish I knew. And I would add to your series of questions: what are the consequences if no significat action is taken?

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