Coral reefs, seagrass beds, mangroves, rocky reefs and shelves are among the most seriously altered ecosystems.
Mason Inman, National Geographic News 14 Feb 08;
No areas of the world's oceans remain completely untouched by humanity's influence, according to a new study.
Every area of the oceans is feeling the effects of fishing, pollution, or human-caused global warming, the study says, and some regions are being affected by all of these factors and more.
A team led by Ben Halpern of the University of California, Santa Barbara, created the first global map that shows the various kinds of damage being done to marine ecosystems.
The team assigned scores to 17 human impacts and tallied them up for every ocean region to reveal the overall effect people are having on marine life.
"The ocean is so big, I figured there would be a lot of areas that we hadn't gotten to or that people rarely get to," Halpern said.
"But when you look at the map, there are huge areas that are being impacted by multiple human activities," he said. "It was certainly a surprise to me."
The project revealed that more than 40 percent of the world's marine ecosystems are heavily affected.
Major hot spots include the North Sea off the northern coast of Europe and Asia's South China Sea and East China Sea.
The study will be published tomorrow in the journal Science.
Acid Oceans, Melting ice
Of all the human effects on marine ecosystems, climate change is having by far the largest overall impact, the researchers estimate.
Greenhouse gases such as carbon dioxide are warming up the atmosphere and, more slowly, the oceans, the scientists explain.
Also, carbon dioxide dissolves into ocean waters, turning them more acidic, which makes it harder for corals, shellfish, and other animals to grow their protective skeletons or shells.
Remote, ice-bound areas in Antarctica and the Arctic are feeling the least impact, the study found, mostly because few people live there and those regions are hard to reach.
But global warming is still affecting those places.
The impacts of warming will continue to get worse, the study notes.
"Projections of future polar ice loss suggest that the impact on these regions will increase substantially," the study authors write.
The second biggest factor affecting marine life is fishing, they add.
Trawl-fishing for animals on the ocean floor, such as groundfish and shrimp, is especially damaging because the rest of the seafloor habitat is destroyed in the process, Halpern says.
The habitats that are suffering the worst impacts, rated "very high" in the study, are continental shelves, the shallow areas off the coasts of continents that are 200 to 750 feet (60 to 200 meters) deep.
Other areas with very high impacts include the northeastern U.S., where pollution, commercial shipping, and fishing are the major causes of harm.
The North Sea and Chinese coasts are hit by almost every kind of impact, Halpern said.
"It's a perfect storm."
Marine Parks
Elizabeth Babcock is a marine biologist at the University of Miami who was not involved in the new study.
"The most useful thing about this [study] is the ability to look at the big picture and to pick out areas that are particularly pristine that would be good places for having marine parks," she said.
The research could also be used to find "areas that are a lot more impacted than anyone thinks, that really need some conservation attention," she added.
"The map is useful for international groups to prioritize where they spend money for mitigation [of these problems] and conservation."
John Pandolfi of the University of Queensland in Brisbane, Australia, said the study "highlights the fact that ecosystems in the sea know no political boundaries. Hence an international, cooperative approach is the only way forward."
The team did not measure the effects of certain practices, such as illegal fishing and aquaculture, the farming of aquatic plants and animals.
"This makes their estimates of habitat decline conservative, and things are probably worse than they outline," Pandolfi said.
Including more local impacts would also paint a bleaker picture, he added.
"A closer look at the nearshore human footprints will probably show a greater degree of degradation," he said.
Yet Halpern remains optimistic.
"My hope is that our results serve as a wake-up call to better manage and protect our oceans rather than a reason to give up," he said.
"Our goal, and really our necessity, is to do this in a sustainable way so that our oceans remain in a healthy state and continue to provide us the resources we need and want."
Man's affect on world's oceans revealed
Nic Fleming, The Telegraph 14 Feb 08;
Almost half of the world's oceans have been seriously affected by over-fishing, pollution and climate change, according to a major study of Man's impact on marine life.
An international team of 19 scientists have published the first ever comprehensive map showing the combined impact of human activity on the planet's seas and oceans.
It shows that more than 40 per cent of marine regions have been significantly altered, while just four per cent remains in a pristine state.
Previous studies have largely focused on the impacts of specific activities such as pesticide runoff or fishing, or have looked at damage in certain areas.
The North Sea is one of the most heavily affected regions, along with the South and East China Seas, the Caribbean, the east coast of North America, the Mediterranean, the Red Sea and the Persian Gulf. The least affected areas are near the poles.
Dr Ben Halpern, of the University of California, presented the new findings at the American Association for the Advancement of Science (AAAS) conference in Boston.
Dr Halpern said: "This project allows us to finally start to see the big picture of how humans are affecting the oceans.
"The big picture looks much worse than I imagine most people expected. It was certainly a surprise to me."
Activities and impacts included in the study include fishing, ocean acidification caused by pollution, temperature change, species extinctions and invasions, and the shipping, oil and gas industries.
The researchers developed models to quantify and compare how 17 human activities affected marine ecosystems.
For example fertiliser runoff has been shown to cause significant damage to coral reefs but has less effect on kelp forests.
They gathered data from across the world and collated the results to give each area a score for man-made damage and changes.
The results, published in the journal Science, show that 41 per cent of the world's oceans and seas have been significantly affected by multiple human activities.
Coral reefs, seagrass beds, mangroves, rocky reefs and shelves are among the most seriously altered ecosystems.
Map shows toll on world's oceans
By Helen Briggs, BBC News 14 Feb 08;
Only about 4% of the world's oceans remain undamaged by human activity, according to the first detailed global map of human impacts on the seas.
A study in Science journal says climate change, fishing, pollution and other human factors have exacted a heavy toll on almost half of the marine waters.
Only remote icy areas near the poles are relatively pristine, but they face threats as ice sheets melt, it warns.
The authors say the data is a "wake-up call" to policymakers.
Lead scientist, Dr Benjamin Halpern, of the National Center for Ecological Analysis and Synthesis in Santa Barbara, US, said humans were having a major impact on the oceans and the marine ecosystems within them.
"In the past, many studies have shown the impact of individual activities," he said. "But here for the first time we have produced a global map of all of these different activities layered on top of each other so that we can get this big picture of the overall impact that humans are having rather than just single impacts."
Co-author Dr Mark Spalding told BBC News that the map was the first attempt to describe and quantify the combined threats facing the world's oceans from human factors, ranging from commercial shipping to over-fishing.
"There's an element of wake-up call when you get maps like this," he said. "Human threats are all pervasive across the world's oceans.
"The map is an impetus for action, I think that it is a real signal to roll up our sleeves and start managing our coast and oceans."
Complex model
The international team of 20 scientists in the US, Canada and UK built a complex model to handle large amounts of information on 17 different human threats.
The researchers divided the world's oceans into 1km-square sections and examined all real data available on how humankind is influencing the marine environment.
They then calculated "human impact scores" for each location, presenting this as a global map of the toll people have exacted on the seas.
The scientists say they were shocked by the findings.
"I think the big surprise from all of this was seeing what the complete coverage of human impacts was," said Dr Spalding, senior marine scientist at The Nature Conservancy, a conservation group in Newmarket, UK. "There's nowhere really that escaped. It's quite a shocking map to see."
He said the two biggest drivers in destroying marine habitats were climate change and over-fishing.
"Out on the high seas, climate change and fishing were far and away the strongest influences," he explained. "The least impacted areas are the polar regions but they are not untouched."
Clear message
The scientists hope the map will be used to prioritise marine conservation efforts.
Andrew Rosenberg, a professor of natural resources at the University of New Hampshire, US, who was not part of the study, said policymakers could no longer focus on fishing or pollution as if they were separate effects.
"These human impacts overlap in space and time, and in far too many cases the magnitude is frighteningly high," he said.
"The message for policymakers seems clear to me: conservation action that cuts across the whole set of human impacts is needed now in many places around the globe."
The findings of the study were presented at the annual meeting of the American Association for Advancement of Science (AAAS) in Boston, US.
Oceans 40% Fouled By Pollution, Fishing, Warming, Study Says
Alex Morales, Bloomberg.com 14 Feb 08;
Feb. 14 (Bloomberg) -- Fishing, pollution and climate change damaged more than two-fifths of the world's oceans, said scientists who produced a map of the human toll on marine life.
Every single square kilometer of the oceans is affected by something man-made, and 41 percent has a "medium high" or "high" impact, the scientists, led by Ben Halpern at the University of California, Santa Barbara, said in an article to be published in the journal Science Feb. 15.
The researchers examined 17 ways that humans affect oceans, including shipping lanes, oil and gas exploration, and invasive species, and mapped the effects across coral reefs, mangroves and continental shelves. The map will help world policymakers protect the oceans, Halpern said in a telephone interview.
"A lot of the past studies have looked at just a single activity -- fishing or climate change or land-based runoff pollution, and they looked at the impact of just one of those," Halpern said yesterday. "We've looked at the overlaying cumulative sum of all of these activities at once, so you can really get a big picture of how humans are affecting the oceans."
Oceans near the poles were unaffected by humans. The North Sea and the South and East China Seas were heavily impacted, said Halpern. The Mediterranean, east Caribbean, Persian Gulf, Norwegian Sea, Bering Sea, the east coast of North America and the waters around Sri Lanka were also among the worst, the article said.
`Degraded State'
"Those areas are definitely in a degraded state, and a state that if people went diving in, probably would not be too happy to be in," Halpern said.
Reefs and mangroves, coastal habitats that receive a lot of attention from conservationists, were heavily damaged by human activities, the study said. Worst were rocky reefs and continental shelves, where commercial fishing concentrates, Halpern said.
"Where you're in a very high impact situation, it's fairly heavily degraded, and the ecosystem is probably not something people would even recognize as a normal healthy ecosystem," Halpern said. "It probably means that most of the big fish and invertebrates are gone and that the plants and animals that live on the bottom are much less abundant than they used to be."
Climate change had the biggest impact on oceans, raising temperature, acid levels and ultraviolet radiation, Halpern said.
Worse Picture
"In coastal areas, you get everything from land-based pollution, and oil and gas development, invasive species as well as climate change and fishing causing problems," he said.
The map created by the scientists doesn't include fish farming or sediment runoff from dammed rivers, said Halpern, who said the group's estimates were conservative.
"There are going to be interactions among these different activities that makes the whole much greater than the parts," Halpern said. "The picture would probably look worse if you accounted for these interactions."
Effective ocean-management can stop the degradation, the study said. Climate change likely will intensify the damage, according to the scientists.
Policy makers should use the scientists' map to separate harmful ocean activities, so negative effects aren't magnified, Halpern said.
"We have business districts and residential districts, schools and churches. All these things are zoned into different places to create some cohesion to our communities that make sense. You don't have a strip club next to a school," the researcher said. "We can allow all these activities to go on, but just not in the same place."
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