Ocean acidification is a major environmental concern. It occurs when salt water PH in the Earth’s ocean drops. The problem has become prevalent due to the increased production of carbon dioxide (CO2) from the burning of fossil fuels, increased agriculture demands, loss of natural oxygen sources, such as forests, and other factors.

Just as these activities raise the levels of CO2 in the atmosphere, they also cause more CO2 to enter the ocean. Seawater will absorb CO2 and carbonic acid is formed.


The result is an acidic environment that cannot support life for different species of marine plants and animals. Ocean acidification’s effects are far-reaching. Increasing acidity interferes with the process of calcium carbonate production.

This means that organisms that naturally grow shells and plates, as well as those that rely on calcified forms for their habitats, are negatively affected. Ocean acidification has been linked to many adverse health effects in marine life, including problems with immunity, metabolic rates, and reproductive behavior. Increased salt water PH is also a major cause of coral bleaching and degradation of coral reef habitats throughout the world’s oceans.

Among many other negative effects on marine organisms, ocean acidification may lead to increased red tide events, which contributes to fish poisoning and can create dangerous circumstances for coastal communities, as well as economic consequences for commercial fishing, tourism, and other industries.

What Happens If Ocean Acidification Continues? 

If the acidity levels continue to increase in the worlds’ oceans, the effects could be disastrous for the biodiversity of marine life, which is likely to lead to the collapse of essential systems. This includes those that are biological as well as societal and economic. A continued rise in acidity levels will mean a loss of livable conditions for many organisms.

This may cause disruptions in food webs, which will likely lead to significant plant and animal population decreases and extinction. This in turn could create scarcity in human food sources, as well as loss of jobs and revenue from coastal recreation and tourism, commercial fishing, and other businesses.

Changes in ocean chemistry will also affect many of the Earth’s natural oxygen sources and capacity to absorb excess CO2. This is what’s known as the ocean’s “buffer capacity”. The loss of buffer capacity will exasperate the build-up of CO2 in the atmosphere, which adversely affects life on land as well as in the ocean.

Credit: NOAA Photo Library

If salt water PH continues to drop at current rates or worsens, ecosystems, industries, and the sustainability of life on the planet will face dire circumstances over the next several decades and into the next century.

What Are Ocean Acidification Solutions?

To stop the increasing acidity of the ocean, several approaches have been suggested. A leading recommendation for reducing ocean acidity levels, is the reduction of greenhouse gas emissions and CO2 generating activities. If global warming is reduced to pre-industrial targets, carbonic acid production in seawater would reduce in turn and ocean acidity levels would drop.

Accomplishing this would require a substantial effort in reaching CO2 reduction targets within the next two decades. Sustainability and emissions reduction goals would also need to occur on a global scale. Geoengineering has also been suggested as an approach to reduce or neutralize ocean acidity. This would involve the use of various chemicals to move PH levels out of the acidic range, but the expense, safety, and effectiveness of this option have been questioned.

Credit: Maike Nicolai

In addition to research gaps on the feasibility of ocean acidification geoengineering, possible risks to marine environments would need to be thoroughly explored. Promotion of phytoplankton photosynthesis through a process known as iron fertilization has also been proposed. Increased oxygen and carbohydrate levels resulting from more photosynthesis could reduce the amount of carbon dioxide that’s absorbed by seawater and turned into carbonic acid.

This could be effective for reducing ocean surface acidification and in more contained environments, such as shellfish farms, but increased production of carbohydrates and oxygen gas could raise acidity levels in deeper ocean waters. Additionally, the cost, timeliness, and ecological safety of iron fertilization has curbed this approach as a large-scale solution to ocean acidification.

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