New map of world’s oceans shows damage by human impact is more than expected.
A Study led by Ben Halpern of the National Center for Ecological Analysis and Synthesis in Santa Barbara, California published in the journal Science, shows that the oceans of the planet are even more damaged then previously thought. Science released the groundbreaking new map of the state of the world’s oceans that has taken four years to produce.
Ben Halpern was quoted as saying that “our results show that when these and other individual impacts are summed up the big picture looks much worse than I imagine most people expected. It was certainly a surprise to me.”
The journal Science reports that the study show “human activity has left a mark on nearly every square kilometer of sea, severely compromising ecosystems in more than 40% of waters.” It described the process involved in the study. “17 anthropogenic stressors, including coastal runoff and pollution, warming water temperature due to human-induced climate change, oil rigs that damage the sea floor, and five different kinds of fishing were weighed by hundreds of scientists who compared the stressors, overlaying them on top of maps that the scientists built of various ecosystems, with data obtained from shipping maps, satellite imagery, and scientific buoys. Then marine scientists modeled how different ecosystems would be affected by the stressors, mapping so-called impact scores onto square-kilometer-sized parcels worldwide. The scores correspond to colored pixels on the new map.”
The Guardian quoted the study as finding the human impact is most severe in the North Sea, the South and East China Seas, the Caribbean, the Mediterranean, the Red Sea, the Gulf, the Bering Sea, along the eastern coast of North America and in much of the western Pacific. It reported that the study found that almost half of the world’s coral reefs have been heavily damaged. Other concerns rest with seagrass beds, mangrove forests, seamounts, rocky reefs and continental shelves. Soft-bottom ecosystems and open ocean fared best but even these were not pristine in most locations.
This study builds on other research like that in Science of 15 August 2003, p. 955 on coral reefs and another Science report of the 25 January 2008 on the desertification of large areas of the ocean that have been expanding.
“The takeaway message of the paper is that one needs to take into account the cumulative effects of different threats to the ocean,” says Duke University marine ecologist Larry Crowder, who wasn’t part of the effort.