Map is first to track global human influences on ocean ecosystems

For a bird's-eye view of human impacts on the Earth, scientists can study satellite images showing the continents in mottled colors that correspond to vegetation, desertification or human habitation. But those photos cannot tell them much about the big blue mystery, oceans, and how human activities affect them.

Now, a team of researchers, including a Stanford University scientist, has constructed the first global map of human influences on marine ecosystems by gathering and interpreting massive amounts of data from the professional literature and from researchers around the world. This study suggests that about 41 percent of oceans bear a serious human "footprint " and that few blue spots on our planet are likely pristine.

"A series of papers have highlighted the role humans are having on the degradation of the oceans, through specific activities," said Fiorenza Micheli, an associate professor of biology at Stanford. "It's timely to put it all together-to show how all the different effects sum up."

Micheli, one of the principal investigators, is scheduled to discuss the project during a press briefing scheduled for 1 p.m. Thursday, Feb. 14, at the American Association for the Advancement of Science (AAAS) annual meeting in Boston. She also will discuss the work, which is described in a paper in the Feb. 15 issue of Science, during a seminar at 8:45 a.m. Friday, Feb. 15.

Micheli said maps of human influence should "guide ocean zoning and management of coastal waters." Scientists increasingly advocate zoning oceans to protect the hidden ecosystems below the surface. "By seeing where different activities occur and whether they occur in sensitive ecosystems, we can design management strategies aimed at shifting activities away from the most sensitive areas," Micheli said.

The researchers compiled data on 17 different human impacts to oceans, including fishing, coastal development, fertilizer runoff and pollution from shipping traffic. Previous studies have worked on a smaller scale, or have focused on only one ecosystem or human activity, examining a single piece of the global puzzle. To make the picture complete, Micheli and her colleagues built a global map detailing how these numerous human impacts would add up and affect 20 types of ecosystems.