Home » Environment » Acidification of The Ocean – Causes and Effects

Acidification of The Ocean – Causes and Effects

by Sekar Puspa

ocean acid, ocean environmentThis day we’ve seen tons of the most popular damaging sequences of global warming like increased heat, drought, and health impacts due to heat and flooding. However, only a fraction of human population are aware that global warming has been destroying the ocean, the very foundation of human life which covers 70 percent of the surface of our planet.

Then, this has been negatively affecting a lot of living conditions on earth. Yet, many people still overlook this just because it hasn’t been directly affecting our life.

Acidity Level

Earth oceans have retained a fairly stable acidity level for millions of years. This is the only possible reason why tons of lavish and wide-ranging chain of life living in the oceans up to this day have emerged and blossomed. Unfortunately, some researches show that this ancient stability of acidity level has been disrupted by a latest rapid drop in surface pH. Regrettably, this could lead to some destructive global consequences.

It’s surprisingly been happening since the early 1800s, when the rise of industrial revolution began. The revolutionary blast of human industry and development went ahead with the start of fossil fuel-powered utilization. Unfortunately, the immediate consequence of this has been the emission of greenhouse gases, particularly billions of tons of carbon dioxide (CO2) or what we call as anthropogenic into the Earth’s atmosphere.

Most scientists in fact are aware that almost more than half of this anthropogenic or man-made CO2 has always been absorbed by the oceans. Moreover it has a benefit in slowing down the climate change because had it remained in the air, these emissions would have instigated. However, some new researches discovered that this enormous amounts of CO2 absorption by the oceans is revamping the stability of the chemistry in the water. This then leads to the disruption of the web of life of various sea organisms, especially the ones at the lower end of the food chain.

Unfortunately, this discovery receives mixed opinions among experts and authorized people. Primarily, the current debate about the connection between CO2 emissions and climate change has greatly disregarded another equally major problem which is the increasing acidity of the oceans. On the brighter side, this recent awareness of ocean acidification has motivated scientists to find the more detailed causes and effect of this marine phenomenon in our life.

Further reading:

  • The Causes

There are several causes in Acidification of The Ocean, as follows:

A. Industrial Fossil Fuel

Ocean acidification is caused mainly due to fossil fuel burning since the industrial revolution when CO2 in the atmosphere began to rise from 280 to 400 million parts per million. This release of CO2 into the atmosphere comes from industry, transportation, energy production, deforestation, agriculture and meat production, and cooling or heating our buildings. This civilization that we live in is very carbon intensive. Up to this moment it is estimated we have released around one quadrillion pounds of CO2 into the atmosphere.

Most people think the oceans are too big to be affected by pollution, but that’s not right. When CO2 levels in the air increase, then the CO2 levels in the oceans will also increase. Actually, because the oceans have a high capability in absorbing CO2, there is approximately about 60 times more CO2 in the oceans than in the atmosphere.

Researches also show that oceans are now absorbing CO2 at a rate of 22 million tonnes in a day and the number keeps rising. Because the oceans absorb roughly around one-quarter of all CO2 emissions, it makes the oceans more acidic.

The Circulation

When CO2 enters and dissolves in the oceans, it immediately reacts with water (H2O) to form carbonic acid. Even though carbonic acid, unlike sulfuric acids or hydrochloric, is considered a weak acid, it is still an acid which contributes hydrogen ions to the ocean.

This lowers the water pH, mainly near the ocean’s surface, towards more acidity. This has been proven obstructing the shell growth of marine creatures.

Over the past 300 million years, ocean’s pH has always been rather basic, averaging around 8.2. Ocean’s pH now though is around 8.1, which is a drop of 0.1 pH units. This means there is around 25 percent acidity increase over the past two centuries.

Just to make it clearer, on for pH scale from 0 to 14, solutions with higher numbers are basic whereas those with low numbers are considered acidic.

It is said that CO2 in the atmosphere has increased up to 390 ppm today from 278 ppm during pre-industrial times. This means the amount of CO2 disintegrated in the ocean has climbed up around more than 30 percent.

Then, it might sound a bit comforting that there is some time lapse between the cause and effect of global warming.

However, even if all the carbon emissions stopped today, we would still have to face another further drop of up to 0.1 units.

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B. Hydrogen Ions

As industrial revolution may affect the ocean acidification the most, there are other things that could be responsible in disrupting the ocean’s chemistry stability. Man-made CO2 isn’t the only aspect that could rise carbonic acid. When marine organisms die on the seafloor, their remains pile up and form corals which then consist of carbons.

These corals release calcium into the water. These compounds actually add acidity, thus they have extensive damaging impact on the composition of the water.

Higher concentration of hydrogen ions in the water could also ruin the stability of ocean’s pH. This particularly happens a lot at the seafloor where some chemical reactions may take place. Those chemical reactions usually includes the increase of hydrogen ions which then could lead to ocean acidification when combined with other compounds like nitrogen and other gases. This of course gives negative impacts on the quality of the ocean water.

C. Waste Disposal

Other than the release of CO2 to the atmosphere through the industrial revolution, disposal of wastes is also another action from industrialization which could damage the ocean water’s composition. It has been a challenge to many countries to reduce this action.

Despite the warning, a lot of manufactory, especially those built alongside the sea have been exploiting the oceans as the practical grounds of industrial or even domestic wastes. So in the end, not only dumped with poisonous gases through the atmosphere, the oceans are once again on the receiving end of toxic liquid wastes.

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D. Agricultural Waste and Wrong Method

On top of direct waste disposal, there are certain industrial or domestic wastes which could greatly increase the levels of acidity in the water. For example, those industrial and agricultural wastes that have acidic compounds. Those particular wastes are extremely dangerous as they lower the pH of the ocean water. Unfortunately even up to this day, the oceans are still the main choice of any type of waste disposal.

This might be surprising to hear for most people, but agriculture could also plays a part in ocean acidification. This mostly happens when agriculture methods that are used by the farmers are not suitable for the agriculture plants. Some of those methods are most likely prone to soil erosion and while in the process, those chemicals are washed downstream into the ocean. So the conclusion is if the agriculture in an area was poorly managed, the oceans could be affected by acidifying soil mineral and water pollution.

The Effects

After causes, its natural if effects occurred, especially in Acidification of The Ocean, such as:

A. Loss of Marine Organisms

As the oceans absorb roughly 22 million tons of human-created CO2 emissions per day, by this number it is projected that by the end of this century ocean pH could be reduced by another 0.5 units with this continued emissions. This could seriously affect shell-forming marine creatures including oysters, corals, lobster, shrimp, some fish like whales and shark, and many planktonic organisms.

When the pH level went down, these organisms would be affected. The increasing acidity makes living inefficient and even almost impossible for some sea creatures which then leads to the extinction or death of some organisms in marine life.

A fairly large fraction of ocean plants and animals, be it the tiny phytoplankton which is the base of marine food web or coral reefs, various shellfish, and molluscs, they all form their shells by integrating calcium and carbonate from seawater into calcium carbonate. Because the ocean pH drops, the availability of carbonate ions shrink. Even below certain pH levels, they will completely vanish and it will be impossible for these ocean creatures to fix their shells or skeletons.

The Process

For the more detailed process, when CO2 meets H2O they produce carbonic acid. Carbonic acid then releases hydrogen ions (H+). These hydrogen ions will bind to carbonate ions (CO32-), forming additional HCO3-. This leads to the decrease of carbonate ions’ concentration in the water which then makes it harder for marine creatures to take one carbonate ions to form calcium carbonate that is needed to form their exoskeletons.

There are two main forms of calcium carbonate that are used by sea creatures, they are calcite and aragonite. The decrease of carbonate ions in the oceans makes the living conditions hard for aragonite users like corals, shellfish, pteropoda, pterotracheoidea, and for calcite users like foraminifera, phytoplankton, and coccolithophore algae. Under a lower pH ocean in the future, there will be an increasing number of these calcium carbonate users organisms that could face noticeable losses or even extinction.

Unfortunately, this is already happening in some place in the world. Since gases like CO2 dissolve more easily in water with colder temperature, ocean acidification is already happening rapidly in the Antarctic and Arctic. Some marine life species in the said areas are already facing challenges and difficulties in fixing their shells and skeletons.

This is an extremely concerning situation for marine life. Scientifics’ awareness of ocean acidification is relatively recent, they are also still at the beginning to study about its effects on marine ecosystems. However, all signs already specify that ocean organisms will have an increasing pressure to adapt to their habitat’s changing chemistry if humans can’t control and eventually eliminate our fossil fuel emissions.

See also: Ocean Natural Resources

B. Food Shortage and The Collapse of Food Chains

Ocean acidification leads to the death and extinction of some marine plants and animals. This will affect greatly on marine food chain as key links are subsided or extinguished. It’s because when some organisms become extinct, their dependents are also put at risk because they have nothing to feed on. When food systems collapse, ecosystems collapse.

That is why ocean acidification also has an impact on marine organisms that don’t need calcium carbonate. Though it is still fairly impossible to predict the exact trajectory of complex marine ecosystems during the increase of acidity, it is still undeniable that the ecosystems will be less productive, less resilient, and less diverse.

Especially when plants and animals at the bottom of food chains like plankton die in large numbers, then animals further up the chain will also die. Moreover plankton is very essential in most of marine food chains, thus if we lose plankton because of ocean acidification, all marine life will be threatened.

Animals Threat

One of the marine animals that would greatly be affected by ocean acidification is blue whales. They practically live on zooplankton, krill, and copepods. Blue whales usually eat 3,636 kilograms of krill daily. There are possibilities that this largest animal on Earth will become extinct when a great amount of plankton suffer from ocean acidification.

The sea butterfly, a swimming snail-like creature in the size of a grain of sand, is another marine creature that plays an important role in most marine food chains. They’re the base of the food chain for many commercial fish, whales, and seabirds. Just like plankton, sea butterfly also needs calcium carbonate to build a thin shell.

Thus, the rise of acidity in the oceans, this type of pteropod will have to rise closer to the ocean surface to build their shell and it will limit their habitat space. Some studies of oceans around Antarctica even show that pteropod’s shells are already dissolving because of ocean acidification.

As ocean acidification is already disrupting marine food chains, it also contributes to the problem of food shortage in human’s food chains. We are also in danger of losing creatures that feed the fish we eat. When fish is out of reach, humans who depend on them for food and livelihood will face huge socio-economic problems. Acidic waters also have more devastating effect on agricultural production which results in the increase in the soil acidity. This then leads to starvation and low production.

See also: Marine Protected Areas


Humans will also be affected by ocean acidification since they depend on oceans water for various purposes. With the ocean water acidity rises, the consumers or the users of the water will also be living in unsafe situation since they will be prone to diseases. Diseases like cancers, for example, can easily be transmitted to humans, especially when they consume fish intoxicated with higher sulfur concentrations.

What can We Do?

There are still a lot of negative impacts of ocean acidification on human life, such as how the fact that as the oceans keep on absorbing a huge amount of CO2 then their capacity as a carbon storehouse could decline. It means more CO2 will remain in the atmosphere which then aggravates global climate change.

However, sure enough, important authorities in the world have started to make a move in an attempt to prevent a more severe ocean acidification. Strict regulations need to be made so human actions can be guarded by policies. Essentially, legislation that should be made have to be able to ensure the waste handling among other pollution-risk activities are controlled. That would help to spread the awareness to the fisheries department to ensure that food consumption will be safe assured.

1. Raising Public Awareness

Another step that could be improved is by raising public awareness about the threat of ocean acidification. International organizations or governments could do something to educate the common citizens about the risks posed by ocean acidification and climate change. Education such as that would also help public to learn about theoretical context as well as real context in understanding the policies.

2. Minimize Using the Fossil Fuels

Not just through education, actions also help reduce the ocean acidification. We in fact can control some extent of high concentration of CO2 in the atmosphere that are caused by human activities. We need to minimize the use of fossil fuels which contributes in emitting CO2 to the atmosphere. Diversification of energy source by using wind and solar as the alternative energy sources can make a lot of positive changes.

See also: Effects of Sea Level Rise

3. Geothermal Term

Another possible option that is also reliable is the geothermal. Other than environmentally friendly, geothermal power can also be an initiative since it comes with less emission of CO2 to the atmosphere. This would also reduce ocean waters’ contamination and ocean acidification.

See also: Effects of Ocean Currents

Other than lessening human activities that release CO2 and other gases to the atmosphere, we can also help by using alternative water sources like using boreholes, wells or tapped rain water instead of ocean water domestically. This will surely help minimize possible ocean water pollution.

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