Owing to the combined effects of climate change, overfishing and pollution, the future of marine ecosystems may appear bleak if these destructive forces continue unchecked. In a new paper published in the Proceedings of the National Academy of Sciences, Dr. Jeremy Jackson analyzes the threats to marine ecosystems and categorizes them according to their overall environmental impacts.
Coral reefs, coastal areas and estuaries, he concludes, are in a state of critical endangerment, while continental shelves are endangered and the open ocean is threatened. Coral reefs are simultaneously one of the most diverse and most threatened ecosystems in the oceans; in fact, Jackson states that the threats are so dire that coral reefs may “virtually disappear within a few decades.”
Currently, one-third of corals are listed as threatened under IUCN criteria due to overfishing and increased sea surface temperatures, which have resulted in a decline in reef grazers and a reduction in coral reproductive success, respectively. In the Caribbean, a reduction in herbivorous fish has caused thick mats of macroalgae to replace living corals at an alarming rate, yielding a decline from 55% to 5% live coral cover over the past 30 years.
Despite Dr. Jackson's dire outlook for coral reefs and other marine ecosystems, all is not lost for the oceans.
We must take a two-pronged approach to saving the oceans, and neither prong is simple. First, we must reduce the threats from pollution and overexploitation to boost the resilience of marine ecosystems, allowing them to deal with the current threats of climate change, and a we must make a serious effort to mitigate climate change so that future threats are averted.
For more on climate change, see http://oceana.org/climate.