A new study conducted by researchers from the University of Washington say that global warming will cause various species from the Equator to swim towards cooler water. While warmer water will speed up the creatures’ metabolic need for oxygen (O2), the warmer water itself will hold less oxygen than ever, drastically limiting the habitat space of marine species.
Curtis Deutsch, lead author and associate professor of oceanography at the University of Washington explains that when your metabolism goes up, you need more food, and also more oxygen. He warns that due to the changes caused by global warming, several marine species could become “oxygen-starved” even if the oxygen levels in the water remain the dame that they’ve always been.
But to make matters worse, he informs that scientists already know that oxygen levels are going down, a d will keep on decreasing. The researchers found that the upper ocean’s metabolic index will be reduced by 20 percent (20%) world-wide, and by 50 percent (50%) in high-latitude northern regions.
The study, published last week, on Friday (June 5, 2015), in the journal Science, compares the fish’s need for more oxygen to that of a mountain climber going through physical exertion while reaching high altitudes where oxygen levels decrease.
For this study, Deutsch and his team of researchers focused on well documented species living in the Atlantic Ocean – cod, rock crab, sharp snout seabream and eelpout – and focused on how their oxygen requirements will impact their habitats in the future.
They used computer generated models in order to calculate how estimated temperatures and oxygen levels will affect theses four (4) species by 2100. As of right now scientists believe that by the end of the century near surface ocean water will warm up by several degrees Celsius, and that it will hold somewhere between 5 and 10 percent (5% – 10%) less oxygen.
Professor Deutsch gave a statement saying that “We found that oxygen is also a day-to-day restriction on where species will live, outside of those extreme events. Ranges will shift for other reasons, too, but I think the effect we’re describing will be part of the mix of what’s pushing species around in the future”.
The results of the projections showed that rock crabs are very likely to restrict their habitats to shallow water due to there being more oxygen near the surface. However, the equator-ward part will become uninhabitable for all four (4) species as the habitat will no longer be able to provide them with the oxygen levels they need.
It’s just the species living in the Atlantic Ocean that will be affected by global warming by 2100. Deutsch says that the Atlantic is a fairly well oxygenated place which means that if there are oxygen restrictions here, then they will most likely be everywhere else as well.
Joanie Kleypas, a marine ecologist at the National Center for Atmospheric Research in Boulder did not participate in the study, but wrote an opinion piece agreeing with the findings. He explains that specific impacts are going to be different from species to species, but that the way it will affect the distribution of marine life will be universal.
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