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
1. What is ocean acidification in simple terms?
Ocean acidification is the ongoing decrease in the pH of the Earth's oceans, caused by the uptake of anthropogenic carbon dioxide (CO₂) from the atmosphere. When CO₂ dissolves in seawater, it forms carbonic acid, which increases the water's acidity. While the ocean is not yet acidic (it remains slightly alkaline), this process is lowering its pH and making it less alkaline than before.
2. What is the chemical process that causes ocean acidification?
The chemistry of ocean acidification involves a series of reactions that occur when CO₂ dissolves in seawater:
- First, carbon dioxide combines with water to form carbonic acid (H₂CO₃): CO₂ + H₂O ⇌ H₂CO₃.
- This carbonic acid then dissociates, releasing hydrogen ions (H⁺) and bicarbonate ions (HCO₃⁻).
- The increase in hydrogen ions (H⁺) makes the water more acidic. These free hydrogen ions then bond with available carbonate ions (CO₃²⁻) to form more bicarbonate.
- This reduces the concentration of carbonate ions, which are essential building blocks for marine organisms to build their shells and skeletons.
3. What are the primary causes of ocean acidification?
The main cause of ocean acidification is the significant increase in atmospheric carbon dioxide (CO₂) released by human activities. The primary sources include:
- The burning of fossil fuels like coal, oil, and gas for energy and transportation.
- Deforestation, which reduces the number of trees available to absorb CO₂.
- Industrial processes such as cement manufacturing, which also release large amounts of CO₂.
The ocean absorbs about a quarter of this excess CO₂, leading to the acidification process.
4. How does ocean acidification affect marine life and ecosystems?
Ocean acidification has widespread effects on marine life, especially organisms that build shells or skeletons from calcium carbonate. Key impacts include:
- Calcifying Organisms: Corals, oysters, clams, sea urchins, and some plankton struggle to build and maintain their shells and skeletons due to the scarcity of carbonate ions. This can lead to weaker structures and slower growth.
- Coral Reefs: It contributes to coral bleaching and slows the growth of coral skeletons, threatening the existence of entire reef ecosystems which support countless other species.
- Fish and Other Organisms: Increased acidity can disrupt the ability of some fish species to detect predators by impairing their sense of smell. It can also affect their reproduction and metabolism.
- Food Webs: The decline of smaller organisms at the base of the food web, like pteropods (sea butterflies), can have cascading effects on larger predators that rely on them for food.
5. If the ocean is still alkaline, why is the process called 'acidification'?
This is an important point of clarification. The term 'acidification' refers to the direction of change in pH, not the final state of the ocean. The ocean's average pH is currently around 8.1, which is alkaline (neutral pH is 7.0). However, since the Industrial Revolution, it has dropped from about 8.2. So, 'acidification' means the ocean is becoming less alkaline and moving towards the acidic end of the pH scale. It does not mean the ocean has become an acid.
6. How are ocean acidification and global warming related?
Ocean acidification and global warming are often called 'the other CO₂ problem' because they are both direct consequences of increased carbon dioxide emissions. Here's how they are related:
- Common Cause: Both are caused by the massive increase of CO₂ in the atmosphere from human activities.
- Different Effects: Global warming is caused by the 'greenhouse effect,' where CO₂ traps heat in the atmosphere, warming the planet. Ocean acidification is a chemical effect caused by the same CO₂ dissolving into the ocean.
They are two distinct but interconnected environmental challenges stemming from the same root cause.
7. Why is the impact of ocean acidification more severe in colder polar regions?
The effects of ocean acidification are more pronounced in colder waters, like the Arctic and Antarctic oceans, for a key chemical reason: gases dissolve better in cold water. Because polar water is colder, it can absorb more atmospheric CO₂ than warmer tropical water. This leads to a higher concentration of carbonic acid and a faster, more significant drop in pH, making these fragile ecosystems particularly vulnerable to the impacts of acidification.
8. What are the potential solutions to slow down or stop ocean acidification?
Since ocean acidification is primarily caused by CO₂ emissions, the most critical solution is to reduce the amount of carbon dioxide in the atmosphere. Key strategies include:
- Transitioning from fossil fuels to renewable energy sources like solar, wind, and hydropower.
- Improving energy efficiency in homes, transportation, and industries.
- Reforestation and afforestation to increase the number of trees that absorb CO₂.
- Supporting international agreements and policies aimed at cutting global carbon emissions.
- Investing in sustainable land-use practices to prevent deforestation.
