What role does the ocean play in carbon sequestration?

The ocean plays a crucial role in carbon sequestration by absorbing and storing large amounts of atmospheric carbon dioxide.

The ocean, covering about 70% of the Earth's surface, is a significant player in the global carbon cycle. It acts as a massive carbon sink, absorbing approximately 25% of the carbon dioxide (CO2) that humans release into the atmosphere. This process is known as carbon sequestration, and it plays a vital role in mitigating the impacts of climate change.

Carbon sequestration in the ocean occurs through two primary mechanisms: physical and biological. The physical process involves the direct absorption of CO2 from the atmosphere. When CO2 comes into contact with the ocean's surface, it dissolves and reacts with seawater to form carbonic acid, which then dissociates to bicarbonate and carbonate ions. This process is known as oceanic carbon uptake.

The biological process, on the other hand, is driven by marine life, particularly phytoplankton. These microscopic plants use sunlight to photosynthesise, a process that involves the absorption of CO2 to produce organic matter and oxygen. When these organisms die, they sink to the ocean floor, effectively trapping the carbon they've absorbed in deep-sea sediments. This process is known as the biological pump.

However, the ocean's capacity to sequester carbon is not infinite and is affected by various factors. For instance, warmer water holds less CO2, so as global temperatures rise, the ocean's ability to absorb CO2 decreases. Additionally, increased CO2 absorption leads to ocean acidification, which can harm marine life and disrupt the biological pump.

In conclusion, the ocean plays a critical role in carbon sequestration, helping to regulate the Earth's climate by absorbing and storing large amounts of CO2. However, this process is under threat due to human-induced climate change, highlighting the need for urgent action to reduce CO2 emissions.