A team of scientists has determined that the warming of the temperature of the oceans at a global level will contribute to increase the greenhouse effect and the levels of carbon dioxide (CO2) in the atmosphere, according to a study published today in the specialized journal PNAS.
The research suggests that the regeneration of CO2 that takes place at the bottom of the oceans can accelerate in many regions of the world, as they heat up with climate change.
“The results tell us that warming will cause faster carbon recycling in many areas, and that means less carbon will reach the depths of the ocean and be stored there,” said lead author Robert Anderson of Columbia University. (USA.)
The oceans absorb approximately a quarter of the carbon dioxide that humans emit into the air each year, which is a powerful brake on the greenhouse effect.
In addition to the purely physical and chemical processes, a large part of this is absorbed by the photosynthetic plankton, since they incorporate carbon in their bodies.
When the plankton dies, they sink, taking the carbon with them.
A part of this organic rain ends up trapped in the depths of the ocean, isolated from the atmosphere for centuries or more.
However, before many of the remains reach far, they are consumed by aerobic bacteria that, like humans, breathe oxygen and expel carbon dioxide, so much of that regenerated CO2 ends up in the air again .
Using data from a research cruise from Tahiti to Peru in 2013, the scientists analyzed two distinct regions: the highly productive and nutrient-rich waters of South America, and the largely infertile waters of the South Pacific.
In the fertile zone, oxygen was rapidly consumed near the surface, as bacteria and other organisms absorbed organic matter.
“People did not believe that much regeneration was taking place in the shallowest area, and the fact that it is happening shows that the model does not work totally the way we thought,” said another author, Frank Pavia.
“This is important,” according to the authors, because researchers project that as the oceans warm up, the minimum oxygen zones (OMZ) will spread horizontally over larger areas and vertically, toward the surface .
Under the conventional paradigm, this would allow more organic matter to reach the deep ocean to be trapped there, but the new study suggests that, while the OMZs are disseminated, so will the regeneration of CO2 at higher levels. (EFEUSA) .-