At a Glance

Typically, the seafloor is milky white and comprised ofthe mineral calcite.Today, excessive carbon emissions have turned the milky white seafloor a murky brown in somehotspots such as the Northern Atlantic and the southernoceans.

Ocean acidification driven by human activityis dissolving the world's seafloors at an alarming rate, a new study says.

Typically, the seafloor is milky white and comprised ofthe mineral calcite (CaCO3), which is formed from the skeletons and shells , according to the study published this week in the journal Proceedings of the National Academy of Sciences in the United States (PNAS).

Today, excessive carbon emissions have turned the milky white seafloor a murky brown in somehotspots, such as the Northern Atlantic and the southernoceans.

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Dissolving calcite helps to neutralizethe acidity of carbon dioxide and prevents ocean water from becoming too acidic. However, levels of carbon dioxide are so high in some areas and the water is so acidic that the calcite cannot meet the demandand is dissolving at a rapid rate.

Researchers with Canada's McGill University say it couldtake decades to see the full impacts of human-caused carbon emissions on the seafloor but the outlook is grim.

“Because it takes decades or even centuries for (carbon dioxide)to drop down to the bottom of the ocean, almost all the (carbon dioxide) created through human activity is still at the surface. But in the future, it will invade the deep-ocean, spread above the ocean floor and cause even more calcite particles ,” lead author Olivier Sulpis of McGill’s Department of Earth and Planetary Sciences said in a press release.

Sulpis noted that the rate at which carbon dioxide is currently being "emitted into the atmosphere is exceptionally high in Earth’s history, faster than at any period since at least the extinction of the dinosaurs."

"And at a much faster rate than the natural mechanisms in the ocean can deal with, so it raises worries about the levels of ocean acidification in future," he added.

The researchers came to their conclusions by simulating the conditions of the deep sea in the lab. They replicated the bottom currents, seawater temperature, chemistryand sediment compositions.

Comparing the dissolution rates from pre-industrial and current times, the researchers determined recent human activity has significantly sped up the process.

"Just as climate change isn’t just about polar bears, ocean acidification isn’t just about coral reefs," noted former postdoctoral fellow David Trossman, now a research associate at the University of Texas at Austin. "Our study shows that the effects of human activities have become evident all the way down to the seafloor in many regions, and the resulting increased acidification in these regions may impact our ability to understand Earth's climate history."