Parts of the bottom of the ocean are disintegrating – and it is our fault | Smart News

Ocean acidification, a byproduct of concern about excess carbon dioxide in the atmosphere, is sometimes dubbed "the equally bad twin of climate change". It is thought that declines in ocean pH have a devastating effect on marine life, eroding corals and making them difficult for some creatures to build their shells and threatening zooplankton survival. Now, as Caroline Haskins relates to Motherboard, a new study has revealed that the effect of acidification extends to the bottom of the ocean, where parts of the seabed are likely to dissolve.

For millennia, the ocean has been very effective at absorbing excess carbon in the atmosphere and regulating its pH. The seabed is covered with calcium carbonate, derived from dead zooplankton shells and sunk to the bottom of the ocean. When the carbon dioxide from the atmosphere is absorbed into the ocean, the water becomes more acidic, but a reaction with calcium carbonate neutralizes the carbon and produces bicarbonate. In other words, the ocean can absorb carbon without "throwing [its] chemistry completely out of control, "as Stephanie Pappas writes in Science live.

In recent decades, however, the large amount of carbon dioxide pumped into the atmosphere has disrupted the balance of this perfected system. Since the beginning of the industrial era, the ocean has absorbed some 525 billion tons of carbon dioxide and the calcium carbonate present on the ocean floor dissolves too quickly to keep pace. As a result, according to a study published recently in PNASsome parts of the seabed disintegrate.

The authors of the study used existing data on water chemistry, seabed currents and calcium carbonate content of deep-water sediments to model the global distribution of water. dissolution of the seabed before and after the industrial revolution. They found that for most ocean floors, dissolution rates before and after industrial processing are actually not very different. But there are several "hot spots" where the bottom of the ocean dissolves at an alarming rate.

Among the main "hot spots" is the Northwest Atlantic, where 40 to 100% of the seabed has been dissolved "in its most intense areas," write the study's authors. In these areas, the "Calcite Compensation Depth", or the ocean layer devoid of calcium carbonate, has increased by more than 980 feet. Olivier Sulpis, a researcher in Earth Sciences at McGill University and lead author of the study, told Haskins that the Northwest Atlantic was particularly affected because ocean currents brought in large amounts of carbon dioxide. . But smaller hot spots have also been found in the Indian Ocean and the South Atlantic.

"[The ocean] just try to clean up the mess, but it's done very slowly and we emit CO2 very quickly, much faster than anything we've seen since at least the end of the dinosaurs, "says Brian Kahn, Sulpis Further.

Ocean acidification threatens coral and hard-shelled marine creatures such as mussels and oysters, but scientists still do not know how it will affect the many other species that live on the bottom of the sea. acidification indicate, the prospects are not very good. Some 252 million years ago, huge volcanic eruptions threw huge amounts of carbon dioxide into the air, causing rapid acidification of the planet's oceans. More than 90% of marine life has been extinct during this time.

Some scientists refer to the current geological period as "the Anthropocene", a term that refers to the overwhelming impact on the environment of modern humans. The authors of the new study believe that burning seabed sediments, once rich in carbonate, will forever alter the geological record.

"The environment of the depths of the sea, it is written, has indeed entered the Anthropocene.

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