Emission of marine animals

The crust of many animals living in the ocean is thinning over time, as seawater absorbs more and more CO ₂ emissions.

A scallop at the bottom of the sea.Photo: Fossil.

Human fossil fuel burning activities have released CO ₂ emissions. Most of the emissions accumulate in the atmosphere and a small percentage is absorbed by the oceans. When CO2 dissolves in water and forms an acid form. The more this gas is absorbed, the more acidic it is and this means that the amount of calcium carbonate (CaCO ₃ ) decreases.

Meanwhile, CaCO ₃ is a mineral that marine animals such as corals and shellfish need to create hard shells. These animals are important links in the ocean food chain. An increase in oceanic acidity can significantly reduce marine animals' ability to create shells, leading to their destruction.

A sudden decline in the quantity of a species will create a negative impact on the whole ecosystem. However, experts have so far relied only on models and experiments to assess the potential impact of greenhouse gas emissions on marine ecosystems.

Australia's Center for Climate Research and Antarctic Ecosystems is exploring this problem in the ocean. They collected thousands of shellfish living in the Antarctic waters to compare with the shellfish trapped in sediments from the bottom before the Industrial Revolution (late 18th century). They found that the 'armor' volume of shellfish today decreased by 30-35% compared to their ancestors.

If the same situation occurs in other oceans, it will lead to dramatic changes in the marine ecosystem. 'The destructive effects brought about by CO ₂ can disrupt the ocean food chain because many of the links disappear,' the Australian team concluded.