{"id":40944,"date":"2015-09-08T08:33:15","date_gmt":"2015-09-08T08:33:15","guid":{"rendered":"http:\/\/www.massarate.ma\/?p=40944"},"modified":"2015-09-08T08:33:15","modified_gmt":"2015-09-08T08:33:15","slug":"warming-oceans-putting-marine-life-in-a-blender","status":"publish","type":"post","link":"https:\/\/www.massarate.ma\/warming-oceans-putting-marine-life-in-a-blender.html","title":{"rendered":"Warming Oceans Putting Marine Life \u2018In a Blender\u2019"},"content":{"rendered":"
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Up in Maine, lobsters are thriving. The Atlantic States Marine Fisheries Commission reported last month that stocks there reached a record high<\/a>.<\/p>\n Down the coast, however, the story is different. In southern New England, lobster stocks have plummeted to the lowest levels ever recorded, putting many lobstermen out of business<\/a>.<\/p>\n Lobster populations rise and fall for many reasons. But in its new report, the commission singled out one factor that is probably driving the recent changes: The ocean is warming.<\/p>\n At the northern edge of the lobsters\u2019 range, higher temperatures may be speeding up their metabolism, leading to the population boom. But at the southern edge of the range, the waters may be getting too warm, putting the animals under extreme stress.<\/p>\n New England\u2019s lobsters are part of a planetwide trend. The oceans have been warming<\/a> in recent decades, largely because of heat-trapping greenhouse gases humans have put in the atmosphere. Many marine species around the world have responded, moving to more comfortable waters.<\/p>\n According to a 2013 study, marine species are pushing their <\/a>range boundaries poleward, away from the Equator, at an average speed of 4.5 miles a year. That\u2019s 10 times as fast as the speed at which species on land are moving.<\/p>\n To understand how rising temperatures will change life in the ocean, scientists are developing computer models to figure out where various species will end up. At this point, the models are fairly simple, but the picture they are painting is stark.<\/p>\n Global warming is going to reshuffle ocean ecosystems on a scale not seen for millions of years. Marine biologists can\u2019t yet say what these new habitats are going to be like.<\/p>\n \u201cIf you put a bunch of species in a blender, you\u2019re not entirely sure what\u2019s going to come out,\u201d said Malin L. Pinsky, a marine biologist at Rutgers University.<\/p>\n The most ambitious effort yet to map the future of ocean life was published Aug. 31 by the journal Nature Climate Change. An international team of scientists analyzed the current ranges<\/a> of nearly 13,000 species of fish, invertebrates and other marine organisms.<\/p>\n The researchers noted the warmest and coldest temperatures in which each species has been observed. If the future plays out like the past, the scientists reasoned, each species will probably move in order to stay in its \u201cthermal niche.\u201d<\/p>\n The journey will be easier for some animals than others, the study found. Some will be able to swim through open ocean to escape overheated waters. Others may find their paths blocked by landmasses or shallow seas.<\/p>\n The scientists also compared the projected biodiversity of each region of the ocean in 2100 with that seen today. The tropics will lose a substantial fraction of their species, the researchers found. And there won\u2019t be any new species emigrating to the tropics to take their place.<\/p>\n As more species shift away from the Equator, they will move into new ecosystems closer to the poles. This migration will produce combinations of species without precedent in the last few million years.<\/p>\n Jennifer Sunday, a marine ecologist at the University of British Columbia who was not involved in the new study, said it represented an important advance in our understanding of the ocean\u2019s future. \u201cThey\u2019ve taken a big step in keeping track of which species are where,\u201d she said.<\/p>\n