August 6, 2013 10:11 am
According to a new study, led by Australian researcher Elvira Poloczanska, marine creatures are heading to the poles. Of all the extra energy trapped on Earth because of global warming, more than 80 percent of it has gone into the world’s oceans. And the animals that live there? They’ve noticed. They’re swimming towards the poles, heading for colder waters, as the ocean warms around them.
Most studies looking at how changing ocean temperatures are affecting marine life have focused on specific animals or specific places, often over a limited time period. Poloczanska and her team were interested in a bigger view, so they pulled together all the information they could find—208 different studies, looking at 1,735 different populations of a total 857 different species of marine animal. (And, for the haters out there, the scientists “included responses irrespective of whether they were consistent with expectations under climate change or not, as well as null responses.”)
Then they looked for big picture trends.
Not every animal that was studied is responding to climate change, they found, but around 82 percent are. And those animals are moving. The team found that, because of climate change, the ranges of these animals are growing towards the poles at around 45 miles per decade, on average. The more mobile critters, like fish and phytoplankton, are moving at around 172 and 292 miles per decade, respectively. This is way, way faster than the 3.75 miles per decade on average that land animals are moving to escape the heat.
So, climate change is here, and the marine critters have noticed. What happens next is the big question. After all, what happens when you tug on the threads of the food web? Poloczanska and her colleagues sum it up:
In conclusion, recent climate studies show that patterns of warming of the upper layers of the world’s oceans are significantly related to greenhouse gas forcing. Global responses of marine species revealed here demonstrate a strong fingerprint of this anthropogenic climate change on marine life. Differences in rates of change with climate change amongst species and populations suggest species’ interactions and marine ecosystem functions may be substantially reorganized at the regional scale, potentially triggering a range of cascading effects.
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