More reef news

[Guest Larry-T]

Human Activities Endangering Caribbean Coral Reefs

HALIFAX, Nova Scotia, Canada, January 9, 2008 (ENS) - Coral reefs in the Caribbean are being degraded by human activities - coastal development, fishing, pollution, and agricultural land use - according to a new study of 322 sites across 13 countries throughout the region.

 

"The continuing degradation of coral reefs may be soon beyond repair, if threats are not identified and rapidly controlled," said author Camilo Mora at Dalhousie University, Halifax. "In the Caribbean alone, these losses are endangering a large number of species, from corals to sharks, and jeopardizing over four billion dollars in services worth from fisheries, tourism and coastal protection."

 

 

Healthy corals near Puerto Rico (Photo courtesy CCRI)

"The future of coral reefs in the Caribbean and the services they provide to a growing human population depend on how soon countries in the region become seriously committed to regulating human threats," Mora said.

 

Published in the current issue of the "Proceedings of the Royal Society of London B," the study includes a comprehensive set of socioeconomic databases on human population density, coastal development, agricultural land use as well as environmental and ecological databases. The data cover temperature, hurricanes, productivity, coral diseases and richness of corals.

 

"It is well acknowledged that coral reefs are declining worldwide but the driving forces remain hotly debated," said Mora.

 

Through statistical analysis, his study shows that the number of people living near coral reefs is the main driver of the mortality of corals, loss of fish biomass and increases in macroalgae abundance.

 

Macroscopic algae, commonly referred to as macroalgae or seaweeds, are large plant like structures commonly found in coastal waters worldwide. An excess of macroalgae can decrease oxygen levels in the water when the algae die and decompose.

 

 

Camilo Mora (Photo courtesy Dalhousie University)

Mora's comparative analysis of different human impacts revealed that the area of cultivated land, with its discharges of agricultural chemicals to coral reefs, was the main driver of increases in macroalgae in the Caribbean.

 

He found that coastal development, which increases the amount of sewage and fishing pressure by facilitating the storage and export of fishing products, was mainly responsible for the mortality of corals and loss of fish biomass.

 

Coral mortality was accelerated even more by warmer temperatures, the study shows.

 

"The human expansion in coastal areas inevitably poses severe risks to the maintenance of complex ecosystems such as coral reefs," Mora said. "On one hand, coral reefs are maintained due to intricate ecological interactions among groups of organisms."

 

"Given the intensity of these interactions, the effects of a threat in any one group may escalate to the entire ecosystem," he said.

 

Mora advises that an ecosystem-based approach for conservation and an integrated control of multiple human stressors are needed if the health of Caribbean ecosystems is to be maintained.

 

 

Agricultural chemicals used on land, such as on these trees in the Dominican Republic, find their way to the sea. (Photo courtesy IICA)

The study also showed that the effective compliance with fishing regulations inside Marine Protected Areas has been successful in protecting fish populations.

 

But coral mortality and macroalgae abundance showed no response to the presence of Marine Protected Areas, MPAs, Mora found.

 

He says Marine Protected Areas in the Caribbean do not safeguard against threats such as land runoffs and ocean warming.

 

"Unfortunately, the degradation of the coral reef matrix inside MPAs may, in the long term, defeat their positive effect on fish populations," Mora said. "This further highlights the need for a holistic control of human stressors."

 

"Although coral reefs will experience benefits of controlling fishing, agricultural expansion, sewage or ocean warming, it is clear that underlying all these threats is the human population," Mora said.

 

"The expected increase of the world's human population from six billion today to nine billion for the year 2050 suggests that coral reefs are likely to witness a significant ecological crisis in the coming half century if effective conservation strategies, including policies on population planning, are not implemented soon."

[Rascal]

Thanks for posting this. It kind of jibes with a lot of what Ousnakebite was saying in his recent post in the last global warming debate thread -- the causes of coral reef decline are a lot more varied and complex than just global warming. While the human impact on climate change can be and is debated, there doesn't seem to be much room for disagreement on who is to blame for higher nutrient levels fueling the growth of nuisance algae. It is undeniably our fertilizers and our poop that runs off into the ocean.

 

I have always been skeptical of the idea that global warming (man-made or not) is THE main cause of coral reef decline. This skepticism comes not from a scientific background or extensive research in the area, but from my own experiences in trying to maintain a healthy reef ecosystem. For example, I know that my reef could easily withstand a few degrees temp change one way or the other, but I am quite sure that if I started peeing, pooping, and adding lawn fertilizer to my top-off water things would go down hill in a hurry. I don't think I'm going out on a limb here if I say that most of my fellow hobbyists would agree.

 

Dropping an anchor into the tank probably wouldn't be too good either.

 

The sad thing is that this story probably won't get nearly the coverage by the mainstream press as one blaming everything on global warming.

 

For the record, my personal opinion is that we should take reasonable steps to reduce CO2 emissions and prevent rainforest destruction if we can -- just because we might be contributing to global warming, and even if the we aren't, I still really like clean air with a lot of Oxygen in it and I don't like acid rain very much because it's bad for fishing. That's just me.

 

The problem I have is that global warming has become such a political darling (the Nobel Peace Prize ???) that it has taken a lot of the focus and attention away from other environmental issues that, in my view at least, are really more important.

 

My rant for the day.

[Guest Larry-T]

Thanks, Rascal,

 

There are too many people who want to make it an all-or-none argument. I don't know of anyone in the environmental community who claims that human activity is THE cause of global warming, but it is clearly evident that human activity has played some role in the increasing levels of CO2 which have led to more extreme swings in the natural cycles. If we can do something to damp these extreme swings we should.