INTRODUCTION TO THE MARINE ENVIRONMENT AND POLLUTION - Marine Pollution: What Everyone Needs to Know - page 18

Ecosystems , a high-resolution map and atlas combining numer-
ous data sets of the world's oceans, was published a few years
ago by a large study group. It reveals that human activities
have strongly affected approximately 40% of the marine area
and have left only about 4% relatively pristine. It covers 17 dif-
ferent types of human activities, including climate change and
fishing, as well as pollution. The authors compiled data from
a variety of sources and fed them into a model that assigned a
single number to each square kilometer of ocean, reflecting the
overall human impact at that spot. The most highly affected
marine areas are the eastern Caribbean, the North Sea, and
Japanese waters, and the least affected ones are around the
poles. The most heavily affected types of environments are
continental shelves, rocky reefs, coral reefs, seagrass beds, and
seamounts. There are few areas of coral reefs, mangroves, or
seagrass beds in the world that are relatively unaffected. While
not all affected areas are affected by pollution, many of them
are. The major types of pollution are excess nutrients (eutro-
phication), marine debris, oil spills, and toxic contaminants.