As an expert in the field of environmental science, I have been closely monitoring the intricate relationship between the Earth's atmosphere and the oceans. The ocean plays a crucial role in the global carbon cycle, acting as a significant sink for atmospheric carbon dioxide (CO2). The absorption of CO2 by the oceans is a complex process that involves both physical and chemical mechanisms.

Firstly, let's discuss the physical absorption of CO2. When CO2 enters the ocean, it dissolves in seawater and forms a weak carbonic acid (H2CO3), which then dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). This process is known as dissolution and is driven by the partial pressure of CO2 in the atmosphere and the solubility of CO2 in seawater. The solubility of CO2 is temperature-dependent, with colder waters generally having a higher capacity to absorb CO2.

Secondly, there is the biological absorption of CO2. Marine plants, such as phytoplankton, utilize CO2 during photosynthesis to produce organic matter and oxygen. This process is similar to the photosynthesis that occurs in terrestrial plants, but it occurs on a vast scale in the oceans, which cover about 71% of the Earth's surface.

The chemical absorption of CO2 is also significant. When CO2 reacts with water, it forms carbonic acid, which can further react with various ions in seawater to form other compounds, such as calcium carbonate (CaCO3), which can precipitate out of the water column and become part of the ocean floor.

Now, addressing the specific question of how much CO2 is absorbed by the oceans, recent estimates suggest that approximately 26 percent of the carbon released as CO2 from human activities, such as fossil fuel burning and cement manufacture, is absorbed by the oceans. This is a substantial amount, considering the total emissions. However, it's important to note that this percentage can vary due to several factors, including changes in ocean temperature, circulation patterns, and the health of marine ecosystems.

The absorption of CO2 by the oceans has significant implications for the global climate and marine life. Increased CO2 absorption can lead to ocean acidification, which can have detrimental effects on marine organisms, particularly those with calcium carbonate shells or skeletons. Moreover, the ocean's capacity to absorb CO2 may be reaching its limits, which could exacerbate global warming if more CO2 remains in the atmosphere.

In conclusion, the ocean's role in absorbing CO2 is multifaceted and critical to maintaining the balance of our planet's climate system. Continued research and monitoring are essential to better understand the dynamics of this process and to develop strategies to mitigate the impacts of human-induced climate change.

read more >>

Recent estimates have calculated that 26 percent of all the carbon released as CO2 from fossil fuel burning, cement manufacture, and land-use changes over the decade 2002-C2011 was absorbed by the oceans. (About 28 percent went to plants and roughly 46 percent to the atmosphere.)Dec 13, 2016read more >>