Ocean Acidification: Causes And Effects

The ongoing decrease in the pH level of the oceans on the earth is termed as ocean acidification. The main cause of the acidification in the oceans is the uptake of atmospheric anthropogenic carbon dioxide by them. Reports say that the surface ocean pH has decreased from 8.179 in 1751 to 8.104 in 1994. Let us see how the uptake of carbon dioxide by the oceans leads to their acidification.

There is a natural equilibrium between the Co2 in the atmosphere and the Co2 dissolved in the oceans. With the increase in the levels of the atmospheric Co2, the levels of Co2 dissolved in the oceans also increases. This is seen especially in the surface waters of the oceans.

The dissolved Co2, then, reacts with the sea water and forms carbonic acid. This is responsible for reducing the pH of the water, thereby increasing its acidification.

The pH level of the oceans has been dropping after the beginning of the Industrial Revolution. Since then (1700s), it has dropped by 0.1 units approximately. Because the oceans continue to absorb anthropogenic Co2, it has been estimated that by the year 2100, the pH level will drop by further 0.3 to 0.5 units.

The impact of these chemical changes on the oceans is severe. These impacts will affect some specific regions and ecosystems more than the others. The southern ocean and the coral reefs are most severely affected by this change.

This process can even kill the corals and make some other species extinct. Other marine animals and ecosystems are observed to have a lesser impact. Acidification may also directly affect the growth and reproduction rates of fish.

The decrease in the pH level in the oceans has negative impact, mainly on the oceanic calcifying organisms. This is so because the concentration of the carbonate ions decreases with the fall in the pH levels. The carbonate thus becomes unsaturated and the species made of calcium carbonate become vulnerable to dissolution.

Ocean acidification is a big problem faced by the world today. The people have to be warned against it. Otherwise, the marine species that you eat may disappear soon.

To reduce the risk of irreversible damage from ocean acidification, it is the need of the hour to take actions that lessen the overall emissions of Co2 into the atmosphere. Ocean acidification can change the ecosystems in the oceans. It is, therefore, essential to reduce the atmospheric Co2. Human activities should be monitored to reach this end.