Courses for Kids
Free study material
Offline Centres

Ocean Acidification

Last updated date: 01st Mar 2024
Total views: 312k
Views today: 8.12k
hightlight icon
highlight icon
highlight icon
share icon
copy icon

What is Ocean Acidification?

Ocean acidification means a significant reduction in the pH level of the ocean over an extended course of time, caused principally by the uptake of carbon dioxide (CO2) from the atmosphere. The pH refers to the potential or power of hydrogen. 

For over 200 years, or since the industrial revolution, the consolidation of carbon dioxide (CO2) in the atmosphere has risen due to the burning of fossil fuels and change in land usage. The ocean absorbs about 30% of the CO2 which is released in the atmosphere, and as levels of atmospheric CO2 rises, so do the levels in the ocean.

Ocean Acidification Causes

Carbon is the criminal. The main culprit behind the acidification in the ocean is the extra amount of carbon dioxide that humans have given rise to in the atmosphere by cutting down forests, burning fossil fuels, and other actions.

Impacts of Ocean Acidity on Ocean Life

The pH of the ocean varies within limits as an outcome of natural processes, and ocean organisms are well-adapted to sustain the alterations that they normally undergo. Some marine species could be able to adapt to more extreme changes—however many would suffer, and there will possibly be extinctions. A more acidic ocean won’t dismantle all marine life in the sea, but the increase in seawater acidity content by 30% that we have observed is already affecting some ocean organisms. Let’s check out how it impacts the atmosphere and habitat:

1. Coral Reefs: 

Acidification may constrain the growth of coral by corroding pre-existing coral skeletons while concurrently slowing the growth of new ones and the weaker reefs that out-turn will be more susceptible to erosion. This erosion will not only emerge from storm waves, but also from animals that pierce into or eat coral.

2. Mussels, Oysters, Urchins, And Starfish: 

Some of the serious effects on these organisms outstrip adult shell-building, but Mussels’ byssal threads, with which they hold on to rocks in the pounding surf, can’t cling well in acidic water. For time being, oyster larvae fail to even start growing their shells. In the initial 48 hours of life, oyster larvae experience a huge growth spurt, building their shells rapidly so they can begin feeding. But the more acidic seawater eats away at their shells before they can develop; this has already induced massive oyster die-offs in the U.S. Pacific Northwest.

3. Zooplankton (Tiny Drifting Animals): 

Oceans consist of the highest amount of actively cycled carbon in the world and are also quite significant in storing carbon. When shelled zooplanktons die and sink down to the seafloor, they carry their calcium carbonate shells along with them, which are accumulated as rock or sediment and stored for the future. This is a crucial way that carbon dioxide is eliminated from the atmosphere, decelerating the rise in temperature induced by the greenhouse effect. 

These little organisms reproduce rapidly so that they may be able to adapt to acidity comparatively better than massive, slow-reproducing animals. However, experiments in the carbon dioxide seeps (where pH scale is naturally low) have discovered that foraminifera are not capable of handling higher acidity very well, as their shells dissolve very quickly. One study even foresees that foraminifera from tropical areas will become extinct by the end of the century.

4. Plants and Algae: 

Plants and various algae may blossom under acidic conditions. These organisms form their energy by combining sunlight and carbon dioxide—thus extra carbon dioxide in the water doesn't harm them, but helps.

How Carbon Dioxide Kills Ocean Life?

Acidification meaning must be clear to you by now. The oceans have always both absorbed and discharged carbon dioxide, commuting the carbon back and forth from the atmosphere to water. But the exchange happened gradually, usually over thousands or tens of thousands of years.

Humans have interrupted that slow exchange. In the middle of the 18th century, humans, since the start of the Industrial Revolution, humans have added some 400 billion tons of carbon to the environment. That’s a byproduct of the massive amounts of fossil fuels we burned for energy, the trees that have been cut down, the cement we’ve generated, and more.

The majority of carbon, in the gas, creates carbon dioxide (CO2), which remains in the atmosphere, where it traps heat and bestows planetary warming. But every year, the ocean sucks up about 25% of all the extra CO2.

FAQs on Ocean Acidification

Q1. What is the Process of Ocean Acidification?

Answer: When CO2 is considerably absorbed by the seawater, a series of chemical reactions takes place leading to an increased concentration of hydrogen ions. This increase induces the seawater to become more acidic and further influence carbonate ions to be comparatively less copious.

Carbonate ions ‘buffer’ this expansion of the number of hydrogen ions by creating more bicarbonate ions. Carbonate ions make way through the oceans by processes such as the weathering of limestone (CaCO3). This buffering reduces the amount of hydrogen and carbonate ions in the oceans. Organisms that develop their shells or skeletons from carbonate will be affected since there are lesser carbonate ions in the oceans.

The levels of ocean acidity may also reach a ‘corrosive’ level where these shells or skeletons begin to dissolve to ‘buffer’ the ocean pH.

Q2. What is the Chemistry Behind Ocean Acidification?

Answer: Carbonate ions are an essential building block of structures such as coral skeletons and seashells. A decrease in carbonate ions can cause buildings and sustaining shells and other calcium carbonate structures very difficult for calcifying organisms like clams, deep-sea corals, oysters, sea urchins, shallow water corals, and calcareous plankton.

These alterations in ocean chemistry could affect the behaviour of non-calcifying organisms as well. Certain fish's competency to detect predators is dwindled down in more acidic waters. When these organisms are at risk, the whole food web may also be threatened.

This is the chemistry behind ocean acidification and ocean acidity is affecting the whole world’s oceans, including waterways and coastal estuaries. Many economies are dependent on fish and shellfish and many people around the globe rely on food from the ocean as their principal source of protein.