for National Geographic News
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.
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