1. Ocean Acidification: Increasing levels of atmospheric CO2 dissolve in ocean water, leading to ocean acidification. This process reduces the pH of seawater and has negative impacts on marine ecosystems, including coral bleaching and reduced growth rates of marine organisms.
2. Calcium Carbonate Precipitation: When lime (calcium oxide) is added to seawater, it reacts with water to form calcium hydroxide, which is highly alkaline. This increases the pH of the seawater.
3. Carbon Capture: The increased pH in the seawater causes a chemical reaction that leads to the precipitation of calcium carbonate (CaCO3) from dissolved bicarbonate (HCO3-) ions in seawater. This process is similar to the formation of seashells and coral reefs.
4. Carbon Sequestration: As calcium carbonate precipitates out of the water, it captures and locks away dissolved carbon dioxide (CO2) into a solid form, effectively removing it from the atmosphere. This process is referred to as carbon sequestration.
5. Reduced Acidity: By increasing the alkalinity of seawater, lime addition can help neutralize some of the excess acidity caused by dissolved CO2, thereby reducing ocean acidity.
However, it's important to note that adding lime to the ocean is a controversial idea, and there is still considerable debate and scientific research needed before it can be widely implemented as a carbon capture method. There could be potential unintended consequences and environmental risks associated with large-scale lime addition, such as impacts on marine life, disruption of marine ecosystems, and alteration of ocean chemistry.
Therefore, carefully evaluating the potential benefits, risks, and ecological impacts is necessary before considering lime addition as a large-scale approach for atmospheric CO2 reduction.
