Is Ocean Acidification Reversible?

Posted on by Team Writer

Is Ocean Acidification Reversible?

Ocean acidification occurs when the pH level of seawater decreases. This is most frequently caused by the ocean absorbing excess CO2 from the atmosphere, which increases as humans contribute more carbon to the atmosphere.

Ocean acidification has severe impacts on marine ecosystems, marine wildlife, and humans. While some researchers argue that ocean acidification can still be reversed to avoid these negative consequences, others disagree.

This article will examine the varying perspectives of experts and researchers on whether ocean acidification is reversible. We will also discuss proposed methods of reversal and the consequences we might face if we fail to reverse ocean acidification.

Background information: Ocean Acidification Infographic

Table of Contents

Ocean Acidification: Is It Really Reversible?

A Pessimistic Stance

An Optimistic Stance

Different Scientific Methodologies On How to Potentially Reverse Ocean Acidification

Future Impact of Ocean Acidification if Not Reversed

Future Impact on People and the Economy

Future Impact on Marine Life and Ecosystems

Key Takeaways

Is Ocean Acidification Reversible? The Debate

Ocean acidification began in the Industrial Revolution of the 19th century, and has been damaging marine life and ecosystems for centuries now.  Today, ocean acidification continues to worsen. Experts in the field are working to identify whether it’s possible to return the ocean’s pH level, or acidity level, to its former condition in the pre-industrial period. In other words, scientists want to know: is ocean acidification reversible?

A Pessimistic Stance

The Secretariat of Convention of Biological Diversity (CBD) introduced a study in 2009 that focused on the impacts and trajectory of ocean acidification. The study collected 300 scientific reports related to ocean acidification and predicted that ocean acidity may increase by 150% by 2050. This increased acidity will likely cause irreversible damage to marine life and ecosystems. According to a 2009 press release, CBD Executive Secretary Ahmed Djoghlaf stated that “Ocean acidification is irreversible on timescales of at least tens of thousands of years.” This suggests that even with significant interventions, fully reversing ocean acidification will be impossible for our generation and beyond. 

This difficulty in reversing acidification is due to the unprecedented speed with which ocean acidification has occurred; post-Industrial Revolution acidification happened 100 times faster than any previous change in acidity over the past 20 million years. Marine organisms and ecosystems are unable to adapt to increased acidity quickly enough, making it difficult to address or reverse.

Post-Industrial Revolution ocean acidification happened 100 times faster than any previous change in acidity over the past 20 million years.
Source: IUCN

Another study was released in 2015, conducted by Germany’s Potsdam Institute for Climate Impact Research. The research focuses on Carbon Dioxide Removal (CDR) methodologies, which utilize technologies to boost the removal of atmospheric CO2, with the goal of reversing ocean acidification to pre-industrial levels. However, the researchers concluded that even if we achieve a 25 gigatons annual CO2 reduction through CDR, ocean acidification will be impossible to reverse to its pre-industrial condition until the year 2700. 

Essentially, even after several centuries of carbon removal, oceans will still show the effects of current acidification.

An Optimistic Stance

In 2013, scientists from Lawrence Livermore National Laboratory conducted an experiment where they designed a sequestration method that works to absorb atmospheric CO2, create clean hydrogen fuels and release carbonate and bicarbonate, which improves alkalinity. The goal of this method is to increase alkalinization, or the chemical process of neutralizing acids to stabilize ocean acidity, in order to reverse acidification.

Another similar study released in 2016 focused on how to reduce ocean acidity through the introduction of an alkaline solution. Rebecca Albright of Stanford University and her team conducted an ocean alkalinization experiment in a series of isolated lagoons surrounded by One Tree Reef, a portion of the southern Great Barrier Reef. The team developed a chemical solution made with a mixture of seawater, dye, and sodium hydroxide, which served as the alkaline (acid-neutralizing) solution that was deposited over the reef of the isolated lagoons. The experiment shows that changes in water chemistry through alkalinization successfully lower ocean acidity, and improve coral development. 

However, the study suggests that ocean alkalinization alone is insufficient to reverse ocean acidification, and that in order to reverse ocean acidification fully, it is necessary to address excessive carbon emissions as well. While reversing ocean acidification may be part of a solution, reducing carbon emissions would address the root of the problem. This is why some argue that ocean acidification is reversible only if it is included in political initiatives that promote a wide reduction of carbon emissions.

Another study was released in 2021 that focuses on enhancing ocean alkalization by introducing experiments on a much larger scale: this time, to the whole Great Barrier Reef. In the experiment, 90,000 tons of alkaline solution were deposited into the Great Barrier Reef every three days for one year. The results reveal that the concentration of carbonate ions increased along the reef, a key indicator of ocean acidity levels. In fact, the experiment successfully reversed acidity levels to the conditions that existed four years ago, indicating that ocean acidification can be reversed on small scales or in small amounts, even if conditions cannot be returned to the pre-industrial conditions of 100 or more years ago. This is promising, as even if we cannot return the ocean to its original state, we may be able to stop the worst of ocean acidification’s effects from taking place.

Scientific Strategies to Reverse Ocean Acidification

Scientists and experts around the world have been studying ocean acidification and how to counter it for decades now. Several scientific methodologies that aim to reverse ocean acidification, including those mentioned above, have already been introduced. Here’s an overview of the methodologies and research that are being considered to reverse ocean acidification.

Enhanced Chemical Manipulation 

One of the main methods scientists are researching to reduce ocean acidification is chemical manipulation. This includes ocean alkalization, or introducing a chemical source of alkaline to the seawater in order to stabilize the acidity levels. This method is believed to reduce ocean acidification at the local scale. 

Ocean alkalization process
Source: Ocean Nets

Carbon Emission Reduction

Because the cause of ocean acidification is the ocean’s absorption of excess CO2 from the atmosphere, one of the main strategies to alter increasing ocean acidification is to reduce carbon emissions globally. This could come through different climate-friendly initiatives and government policies, including but not limited to: 

  • Switching to renewable energy sources
  • Implementation of carbon taxes
  • Driving low carbon vehicles, or using electric vehicles
  • Using bicycles and low-carbon forms of transport more often
  • Using energy-efficient appliances
  • Planting more trees

Surface Acidity Pumping

Several recent studies have suggested addressing ocean acidification with surface acidity pumping, the use of electrochemical pumping to relocate surface seawater acidity to the depths of the ocean. This method decreases the acidity level of the surface seawater by bringing up alkaline water from the bottom of the ocean, and then relocating surface acidity to the bottom. This strategy not only controls ocean acidification and benefits coral reefs’ health, but also allows the ocean to capture more atmospheric CO2, which may help to mitigate global warming.

pumping process - is ocean acidification reversible
Electrochemical pumping process
Source: Energy & Environmental Science Tyka et al. 2022

Read more about this strategy: Researchers propose controlling ocean acidity to lower atmospheric carbon dioxide

Future Impacts of Ocean Acidification if Not Reversed

If the current rate of ocean acidification is not reversed, it will have a detrimental effect not just on the environment, but also on the global community. Here are some examples of how ocean acidification will affect humans, the economy, marine species, and ecosystems in the future.

Impact on People and the Economy

Impact on the Aquaculture Industry 

Ocean acidification affects the development and survival of shell-forming marine animals, including oysters, clams, mussels, and many more. This variety of marine animals is widely produced, farmed, and consumed on the global seafood market. With these animals at risk, the shellfish and seafood market might collapse, which may cause job loss and economic fallout, especially in countries and regions that rely on shellfish farming. 

Other fish may also be hard to find on the market as an indirect result of ocean acidification. Salmon and tuna, for example, are two of the most popular seafoods on the market. These fish rely on other smaller fish for food, such as sardines and anchovies. These smaller fish feed mostly on phytoplankton, which is one of the organisms most severely affected by ocean acidification. The imbalances ocean acidification creates in the ocean food chain have an impact on the survival of these popularly-marketed fish. If ocean acidification continues to worsen, much of the seafood that we not only enjoy, but also that generates income and employment and contributes to the economy may not be available decades or centuries from now.

Impact on the Tourism Industry 

The tourism industry is one of the largest contributors to the world economy, but it is also threatened by ocean acidification’s impacts. For example, coral reefs attract tourists, which generates $36 billion for the global economy annually. Many regions rely on coral reefs to generate employment and business. Unfortunately, ocean acidification is already causing massive coral deaths in different parts of the world. If ocean acidification is not reversed, coral population declines will continue, which may create a negative effect on the tourism sector, resulting in job losses and business closures that will negatively impact the people that rely on them.

Impact on Marine Life and Ecosystems

Experts, researchers, and scientists have shown that ocean acidification is already creating detrimental impacts on different marine life and ecosystems. This includes the following discoveries:

  • Ocean acidification is negatively affecting the population and development of phytoplankton and diatoms.
  • Ocean acidification makes it difficult for coral to build their skeletons, which creates an ecological imbalance, and a non-habitable environment for reef fish species. 
  • Ocean acidification negatively affects the capabilities of shell-forming marine species, such as clams, sea urchins, oysters, and mussels, to grow and develop their shells, making them more vulnerable. 
  • Ocean acidification negatively affects salmon’s sense of smell and ability to detect danger. 

All of the scientific discoveries listed above threaten the affected species, and may even lead to an increase in their mortality rate in the long run. Experts are concerned that if we do not stop or reverse ocean acidification, we may witness a repetition of the historical mass extinction that occurred 66 million years ago, when 75% of marine species became extinct due to an overly acidified ocean. If this happens in the future, the damaging impact of this may not only affect the marine life and ecosystem but all life on earth.

Key Takeaways

The possibility of reversing ocean acidification is uncertain. The main arguments can be summarized into three categories:

  • Some argue that ocean acidification is not reversible (especially not to pre-Industrial Revolution levels).
  • Some argue that we can slow ocean acidification down, but not reverse it completely.
  • Some argue that it is scientifically feasible to reduce acidification at least enough to avoid catastrophic consequences. 

While ocean acidity levels likely cannot be returned to pre-Industrial Revolution levels, ocean acidification can be reduced on local scales to the acidity conditions of a few years ago (which is still a much-needed improvement).

Experts are working to find strategies to make this possible, although many of these strategies have not been tested on a larger scale. But one thing is certain about the question, is ocean acidification reversible: Reducing or reversing ocean acidification requires a global unified effort to reduce carbon emissions. If we succeed in achieving this, then the answer might be yes.

How Are Whales Affected by Ocean Acidification?

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Ocean acidification occurs when the pH level of seawater decreases, which is most frequently caused by the ocean absorbing excess CO2 from the atmosphere. Ocean acidification has negative effects on a variety of ocean ecosystems and life forms, including whales.

This article will explain how whales are affected by ocean acidification and the importance of whales to ecosystems.

Background information: Ocean Acidification Infographic

Table of Contents

How Are Whales Affected by Ocean Acidification?

The Importance of Whales

Historical Whale Population Decline and Recovery

Whale Conservation Efforts

How Are Whales Affected by Ocean Acidification?

Whales are affected by ocean acidification in numerous ways. 

how are whales affected by ocean acidification

First, whales may suffer from starvation and other diseases due to ocean acidification’s effects on their food supply. The increase of ocean acidity decreases the number of carbonate ions. This ion is essential to most shell-forming organisms including krill, which is the primary source of food for baleen whales, including blue whales and humpback whales. Without enough krill to sustain the whales, they can starve or seek alternate food sources, which may not give the appropriate nutrients the whales need, leading to malnutrition and other diseases.

There are also some studies theorizing that ocean acidification may affect the hearing abilities of whales and dolphins. This is important because hearing is crucial for whale communication.  As the oceans become more acidic, the concentration of borate in the water decreases, which could affect the absorption of sound energy that whales rely on for communication. However, this theory was countered in a 2010 study, in which researchers from the Woods Hole Oceanographic Institution argued that acidification will only have a minimal effect on whales’ ability to communicate.

In summary, ocean acidification may contribute to decline in whale populations. This could become a serious problem for ocean ecosystems and climate change, as whales help to maintain balance in the ocean and atmosphere.

The Importance of Whales

Whales play a crucial role in maintaining balance in the ocean ecosystem, which helps marine life and people alike. Ocean acidification threatens the important services that whales provide. Here are some of the important roles of the world’s largest mammals.

Food Chain Guardians

In their place at the top of the food chain, whales play a very important role in maintaining the balance of the marine ecosystem and the supply of food in the ocean. For example, each day, a blue whale or a humpback whale can eat up to 40 million krill. Due to this massive appetite, overpopulation of krill is prevented, which helps preserve the ecological balance of the marine ecosystem.

Natural Nutrient Suppliers

whale deposits - whales ocean acidification
A blue whale leaving a massive amount of nutrient-rich deposits
Source: Ian Weisse / abc news Australia

Whales also act as fertilizer transporters in the ocean. Whales contribute to ocean fertilization through their deposits and urine. According to research, a sample of whale fecal matter contains 10 million times more iron than the amount of iron present in a sample of ocean water of the same weight. These nutrients are essential to the health and reproduction of different marine organisms, including phytoplankton (which help reduce ocean acidification). Because whales are migratory animals, they supply these nutrients to different ocean locations. 

Climate Change Fighters

Phytoplankton usually thrive where whales are found. This is because whale deposits fertilize phytoplankton, which allows plankton to reproduce and thrive. Each year, phytoplankton absorb around 10-20 billion tons of CO2 from the atmosphere, and are considered the world’s largest producer of oxygen, as they help account for 70% of the world’s oxygen supply. Without the nutrients whales provide, phytoplankton might not flourish, which could greatly affect the ocean’s carbon cycle and increase ocean acidification. 

Historical Whale Population Decline and Recovery

The population of whales started to decline in the 11th century as a result of the growing whaling industry. People hunted whales for oil and other products, including meat, baleen, and ambergris. This activity continued for centuries, causing the populations of different whale species to drop drastically, driving them to extinction.

whaling industry - whales ocean acidification
Soviet whalers during the 20th century.
Source: Hakai Magazine/ Popperfoto/Getty Images

In 1986, the International Whaling Commission (IWC) banned commercial whaling. Because of this, whales are finally able to recover and repopulate. Today, most of the whale species that experienced the decline are now showing some population recoveries. Here is the recent population status of some well-known whale species: 

Humpback Whales 

Today, the humpback whale population reaches about 80,000 as a result of global conservation efforts and policies. 

Fin Whales

Fin whales were one of the most hunted whales during the whaling era of the 20th century, but today, their population is considered healthy, reaching about 75,000.

Blue Whales

Today, blue whale populations are still pushing for recovery. Even though their population is increasing, they are still listed as endangered. The current population of blue whales is between 10,000 – 25,000.

Though ocean acidification is not listed as one of the main sources of whale mortality today, several man-made factors are still causing death to different kinds of whales. This includes: 

  • Ship strikes
  • Plastic pollution
  • Fishing nets entanglement (bycatch)
  • Climate change

Whale Conservation Efforts

Globally, different organizations and government agencies are working to conserve and increase the population of whales. Since ocean ecosystem health is declining due to pollution, ocean acidification, and overfishing, whales and their sources of food are at risk. It is important that we work to conserve them, because they provide us with important services, including (indirectly) the air we breathe.

Here’s an overview of some whale conservation organizations:

World Wildlife Organization

  • For 50 years, the WWF has been running programs to protect whales. The organization participated in the petition banning commercial whaling in 1984.  
  • The organization’s goal is to protect whales and dolphins using three methods: 
    • Improving whale monitoring and mitigating bycatch (accidental entanglement in fishing traps)
  • Preventing ship strikes and reducing underwater noise pollution
  • Protecting whale habitats

Ocean Alliance 

  • Ocean Alliance focuses on increasing public awareness of the importance of whales. 
  • Through the production of 40 documentaries, the organization serves as the bridge between whales and the global community, allowing people to better understand whales and their purpose.

Whale and Dolphin Conservation

  • Whale and Dolphin Conservation has been working on whale conservation efforts for 30 years. The organization has been successful in its mission in various ways: 
    • Stopping commercial whaling
    • Preventing and fighting against whale captivity
    • Preventing and reducing entanglements (bycatch)
    • Promoting sanctuaries and protected areas for whales and dolphins 

How Are Sea Urchins Affected by Ocean Acidification?

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Ocean acidification occurs when the pH level of seawater decreases, which is most frequently caused by the ocean absorbing excess CO2 from the atmosphere. Ocean acidification has negative effects on a variety of ocean ecosystems and life forms, including sea urchins.

This article will explore how sea urchins are affected by ocean acidification, as well as the importance of sea urchins to ecosystems, global cultures, and the economy.

Background information: Ocean Acidification Infographic

Table of Contents

How Are Sea Urchins Affected by Ocean Acidification?

The Importance of Sea Urchins

The Importance of Sea Urchins to the Ecosystem

The Importance of Sea Urchins to People and the Economy

How Are Sea Urchins Affected by Ocean Acidification?

Sea urchins are vulnerable to ocean acidification because rising acidity in seawater reduces the number of available carbonate ions, which are essential for building sea urchins’ shells, spines, and teeth. Here are some of the negative effects of ocean acidification on sea urchins. 

Lowered Growth Rate of Sea Urchin Larvae

Because larval sea urchins are quite sensitive, ocean acidification affects the development of sea urchins at very early stages. According to a 2022 study, sea urchin larvae’s growth rate is lowered when they’re exposed to acidified water. Sea urchins, when exposed to lower pH seawater, need to use extra energy for other survival functions, including temperature self-regulation, leaving insufficient energy for them to use for their growth.

Increased Metabolism

Sea urchins feed on various types of marine organisms, including algae, planktons, and even kelp. Feeding is crucial to the growth, development, and survival of sea urchins. However, 2013 research discovered that increasing ocean acidity affects the metabolism of sea urchin larvae, forcing them to eat more than normal. A lower pH level reduces the capability of sea urchin larvae’s digestive enzymes, known as “gastric juice.” In order to attempt to make up for less effective digestion, sea urchin larvae exposed to acidification increased their feeding by as much as 33%. If this increased eating was not possible due to a lack of food, the sea urchin would suffer. Additionally, this increased energy devoted to eating reduces energy reserves for other vital functions such as growth and temperature self-regulation.

Increased Developmental Abnormalities and Mortality Rates

Ocean acidification forces sea urchins to reallocate their energy sources in order to adapt. This might sound positive, but experts have found that it is one of the causes of mortalities and abnormalities in sea urchins. In a 2022 experiment, sea urchin larvae were exposed to acidified water with a 7.2 pH level (much lower than the ocean’s current pH of 8.1). This showed a significant effect, causing abnormalities to the sea urchin’s structural development. 

In the same experiment, when larval sea urchins were exposed to acidified water with a pH of 7.2, they were unable to grow into juvenile sea urchins. These abnormalities may threaten their survival rate.

sea urchin study - sea urchin ocean acidification
Comparison of two sea urchins, where the sea urchin on the right is exposed to ocean current conditions, and the sea urchin on the left is exposed to ocean acidification.
Source: Phys.org

The Importance of Sea Urchins

Sea urchins contribute to the ecological balance in the ocean ecosystem and provide products that are used in traditional cuisines. However, ocean acidification threatens sea urchin populations, and thus, the benefits they offer to ecosystems and people. Here are some of the ways sea urchins are important to ecosystems and people.

The Importance of Sea Urchins to the Ecosystem

Reef Gardeners 

Sea urchins are herbivores and they feed on algae and other marine plants in the reef. Their feeding activities are essential to the balance of the reef because as they remove overgrown weeds and algae, they create room for corals to flourish. This provides more habitat for fish while also preventing the negative effects of overgrowing algae on the reef.

This service that sea urchins provide plays an essential role in maintaining a healthy and habitable marine ecosystem. They are great alternatives to the decreasing population of other algae controllers that are commonly overexploited by people, such as parrotfish and rabbitfish. If ocean acidification continues, the service of sea urchins to reef maintenance could be affected. Without sea urchins and other algae controllers, the reefs as we know them might become uninhabitable for many organisms in the future. 

Source of Food for Other Species

sea otter eating urchins - sea urchin ocean acidification
Sea otter eating sea urchins
Source: Katherine johns / listal

Sea urchins are a food source for several other species. Sea urchins’ high protein provides essential nutrients to animals that rely on this diet. Animal species that feed on sea urchins include:

  • Other shellfish, such as crabs and lobsters 
  • Multiple fish species, such as sheephead wrasse and wolf eel
  • Sea otters
  • Seagulls

Some of these animals use sea urchins as their primary source of food, which is why the negative impact of ocean acidification doesn’t only affect sea urchins directly; it can also cause an indirect effect on species that rely on their services. 

The Importance of Sea Urchins to People and the Economy

How Sea Urchins Benefit the Cultural Food Industry and Economy

Like any other commercialized shellfish on the market, sea urchins are also in demand in some countries’ food industry. Here is an overview of some of the countries that use sea urchins as part of their food industry. 

Chile

Chile has a long tradition of eating sea urchins, as sea urchins have been part of Chilean food since the 1500s. Today, sea urchin is still a part of the Chilean diet. In 2002, Chile consumed around 3,000 tons of sea urchins, and in 2013, Chile ranked as the world’s largest supplier of fresh and frozen sea urchins and urchin roe. Sea urchins are not only a part of Chilean tradition and culture, but they also make a significant contribution to Chile’s economy today.

Japan

sea urchin sushi - sea urchin ocean acidification
Sea urchin sushi
Source: Sushi Making Kit

Eating sea urchins in Japan is traditional, with consumption accounting for around 90% of the global supply. Japan is the largest consumer of sea urchins in the world, where it is commonly eaten as sushi and sashimi, two of Japan’s most iconic dishes. The sea urchin also contributes significantly to Japan’s economy since the country is considered a major exporter of sea urchins globally.

The population of sea urchins may decline as a result of the effects of ocean acidification. This could have a damaging effect not only on the economic contribution of sea urchins, but also on culinary cultures that have been passed down for centuries. 

Health Benefits from Sea Urchin in the Diet

Despite their threatening appearance, sea urchins can provide various health benefits and nutrients to people. Here are some examples: 

  • Sea urchins are high in protein, which can help maintain and grow our muscles.
  • Sea urchins are also rich in dietary fibers that are good for digestion.
  • Sea urchins contain vitamin C and Zinc, which are great for the immune system.
  • They also contain vitamin A, which is good for our organs, such as the heart, kidneys, and lungs.
  • Just like other fish, sea urchins are rich in omega 3 fatty acids, which are useful for maintaining a healthy heart.

Sea urchins provide a variety of valuable benefits to the environment, wildlife, and humans. Several studies have already proven how the acidifying ocean affects their development, preventing them from thriving. This could alter the important services they provide that help in maintaining ecological balance. This is why it is essential to assure that sea urchins, like all other species, are protected from the damaging consequences of ocean acidification.

How Are Salmon Affected by Ocean Acidification?

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Ocean acidification occurs when the pH level of seawater decreases, which is most frequently caused by the ocean absorbing excess CO2 from the atmosphere. Ocean acidification has negative effects on a variety of ocean ecosystems and life forms, including salmon.

This article will explain how salmon are affected by ocean acidification, as well as the importance of salmon to ecosystems, people, and the economy

Background information: Ocean Acidification Infographic

Table of Contents

How Are Salmon Affected by Ocean Acidification?

The Importance of Salmon

Ecosystems and Wildlife

People and the Economy

How Are Salmon Affected by Ocean Acidification?

salmon ocean acidification
Source: Timothy Knepp

Salmon and other fish species feel the impact of ocean acidification. As acidity levels rise in the ocean, chemical imbalances are created within their bodies, which are normally balanced with the pH of the surrounding water. This can affect salmon’s behavior and abilities. Here are some of the ways ocean acidification negatively affects salmon.

Ocean Acidification Affects Salmon’s Ability to Sense Danger

Salmon are known for their extreme sense of smell, which is essential for them to search for food and avoid predators. However, when ocean acidification rises, salmon’s ability to smell is altered. According to a 2018 study, salmon that have been exposed to acidified seawater stop showing a response to the scent that tells them there’s danger nearby.

In the study, researchers created three separate salmon tanks, each with a different level of seawater acidity. After two weeks of exposure to the water, salmon in the tank with the lowest acidity levels exhibited normal reactions when the “danger scent” was put into the water. In fact, most of the time, the low-acidity salmon entirely avoided the section of the tank where the scent was coming from. On the other hand, salmon in the tank with the highest acidity levels did not respond to the “danger scent” at all, and made no attempts to avoid it.

The study reveals that ocean acidification can negatively affect salmon’s ability to sense danger. This may result in an increased mortality rate and population decrease in salmon exposed to ocean acidification.

Watch how acidic water affects salmon’s sense of smell in this demonstration from the University of Washington:

Ocean Acidification Affects Salmon’s Ability to Navigate Home

Salmon are anadromous, which means that as they mature, they migrate from the ocean to their natural spawning grounds in rivers to lay eggs. They use their extreme sense of smell to navigate the seas and rivers. This phenomenon is essential for salmon to reproduce and thrive. Unfortunately, the effects of ocean acidification on their sense of smell alter their ability to navigate home. This could prevent them from reproducing and spawning, which could also contribute to declines in their population. 

Ocean Acidification Reduces Salmon’s Food Sources

In the wild, salmon mainly feed on crabs, krill, and shrimps. the negative effects of ocean acidification may impact the populations of shell-forming organisms, including many species that salmon commonly rely on for food. This could lessen the availability of salmon’s food sources, which could lead to starvation, or changing their diet. This might result in a decline in the essential nutrients salmon get from their original diet to sustain their characteristic pink features and health. In the long run, this may raise their mortality rate, reducing their population.

The Importance of Salmon

Salmon play an important role in maintaining healthy ocean and river ecosystems. They also provide benefits for marine wildlife, terrestrial wildlife, and people. However, the increasing threat of ocean acidification puts the important services that salmon provide at risk. Here are some of the ways salmon are important to ecosystems, wildlife, and people.

The Importance of Salmon to Ecosystems and Wildlife

Natural Nutrient Transporter

Since salmon are anadromous, they contribute to the transportation of nutrients from the ocean to rivers and streams. For example, in Alaska, approximately 170 tons of phosphorus are transported from the oceans to Lake Illiamna annually due to the migration of sockeye salmon. Aside from phosphorus, salmon also provide nitrogen to rivers, streams, and lakes. After they lay eggs, salmon die and release nitrogen into the waters. Phosphorus and nitrogen are essential to the growth of microorganisms and vegetation, and provide necessary nutrients to wildlife that inhabit the lake.

Food Source for Wildlife

Salmon serves as food for various types of marine and terrestrial animals. Here are some of the species that rely on salmon as their source of food:

  • Brown bears rely on a salmon diet for the rich calories it provides. Salmon are essential for bears, as bears need to consume around 5,000 to 20,000 calories per day, depending on the season.
  • Sharks, seals, and orcas consume salmon in the ocean. Salmon provides nutrients that are essential for their growth.
  • Bald eagles and other predatory birds that live on riversides feed on salmon when the fish return to their spawning grounds in shallow rivers and streams.
Alaskan brown bear catching salmon in Brooks Falls
Source: Gary Lackie/Flickr

The consequences of ocean acidification may have an impact on the availability of salmon in areas where animals and plants rely on them for nutrients and food. If the ocean continues to acidify, it will not only harm salmon, but will also have a detrimental domino effect on the ecosystem and other species that rely on the fish.

The Importance of Salmon to People and the Economy

How Salmon Benefit the Aquaculture Industry 

Industrialized salmon farming started in the 1980s in Norway and quickly grew into a global industry. Today, salmon aquaculture is one of the fastest growing methods of food production today, and makes up about 70% of the global market. Salmon have a huge impact on the global economy, so the effects of ocean acidification on salmon could be quite disruptive. 

How Salmon Benefit People’s Livelihoods 

In 2018, almost 60 million people relied on the aquaculture industry for their source of income. Because salmon is the most-produced fish in the global aquaculture industry, it provides millions of people with employment and income. 

Health Benefits of Eating Salmon

salmon on plate - salmon ocean acidification

In the 1980s, salmon was considered a fancy dish in some countries, but as the industry grew salmon became more widely available, and the health benefits and nutrients it provides to humans spread to practically every corner of the globe. Here are some examples of the health benefits of salmon:

  • Salmon is a good source of protein, which is essential to building muscle mass and growth. 
  • Salmon is rich in vitamin b12 and iron, which are essential to the formation of red blood cells. This can prevent blood-related conditions like anemia. 
  • Salmon contains potassium, which is essential in maintaining healthy muscle condition and nerve function.
  • Salmon also contains vitamin D, which boosts immune systems. 
  • Salmon contains high omega 3 fatty acids. This is great for maintaining a healthy heart and reducing the chance of getting several diseases such as heart attacks, cancer, dementia, and Alzheimer’s. 

The issues salmon face from ocean acidification are exacerbated by the negative pressures humans have placed on salmon populations. This includes urbanization, pollution, and dam constructions. If worsening ocean acidification is added to these pressures, salmon may not be able to continue to adapt to declining environmental conditions, and their populations will suffer.

Salmon provide a variety of services and health benefits to people, the economy, wildlife, and ecosystems, but they are threatened by ocean acidification. Ocean acidification jeopardizes the benefits we get from salmon and it may also create an ecological imbalance that could lead to other species’ extinction. 

How Are Diatoms Affected by Ocean Acidification?

Posted on by Team Writer

Ocean acidification occurs when the pH level of seawater decreases, which is most frequently caused by the ocean absorbing excess CO2 from the atmosphere. Ocean acidification has negative effects on a variety of ocean ecosystems and life forms, including diatoms, a type of phytoplankton characterized by glass-like cell walls made of silica.

This article will explain how diatoms are affected by ocean acidification, and will discuss the importance of diatoms to ecosystems and people.

Background information: Ocean Acidification Infographic

Table of Contents

What Are Diatoms?

How Are Diatoms Affected by Ocean Acidification?

The Importance of Diatoms

The Importance of Diatoms to the Ecosystem

The Importance of Diatoms to People

What Are Diatoms?

Diatoms are one of the two common types of phytoplankton. They are found in bodies of water such as the ocean, rivers, lakes, and ponds, as well as in mud and moist soils. Diatoms are commonly recognized by their transparent glass-like cell walls made out of silica acids (a type of mineral) that are dissolved in water. Just like corals and other marine plants, diatoms photosynthesize in order to survive, which is why sunlight and carbon are essential to their survival. Diatoms also play a vital role in transferring atmospheric carbon to the deep ocean, which helps to prevent global warming and reduce ocean acidification. 

To give you a better grasp, here is a short video explanation and microscopic footage of diatoms by MicroBiome:

How Are Diatoms Affected by Ocean Acidification?

Despite their small size, diatoms play an important role in ocean ecosystems and studies are revealing the risk ocean acidification poses to their wellbeing. Diatoms rely primarily on CO2 for their photosynthesis, so the ocean’s increased absorption of CO2 that causes ocean acidification has a large impact on the creatures. Here are some of the effects of ocean acidification on diatoms.

Ocean Acidification Could Increase the Growth of Diatoms

According to a 2019 study, high CO2 levels due to ocean acidification could increase the metabolism and growth of diatoms. This is because diatoms rely on CO2 as their source of energy in photosynthesis. However, the study’s results are still being debated and there is no final agreement on how these factors would affect the diatom community, nor how diatoms will continue to adapt to the acidifying ocean.

Ocean Acidification Slows the Development of Silica Cell Walls

ocean acidity ph scale - diatoms ocean acidification

Diatoms build their silica cell walls to protect themselves against predators such as krill. The cell wall is an important factor for their survival. According to a 2019 study published in Nature, exposure of diatoms to ocean acidification could slow their development of silica cell walls. The study reveals that even when the ocean pH level drops to 7.84 (compared to today’s pH of 8.1), the development of diatom’s silica cell walls reduces. Not only can this affect the ability of diatoms to survive, but it can create an imbalance in the ocean’s silica levels. Even small shifts in ocean acidity can have major impacts.

Ocean acidification may also impact the ability of diatoms to dissolve their shells, leading them to sink into the deep ocean. This reduces their population by making it difficult for them to get light from the surface, reducing their ability to photosynthesize to survive.

Read more: New Research Shows Unexpected Negative Impacts of Ocean Acidification on Diatoms

Ocean Acidification Could Alter the Efficiency of Diatoms’ Transport OF CO2 to the Deep Ocean

Diatoms play a big role in carbon sequestration. When they die, diatoms sink to the deep ocean with the help of their silica cell walls that serve as a weight and stabilizer. This process works to transport all the CO2 the diatoms have absorbed to the ocean’s depths, thus sequestering it in the deep ocean and removing it from the atmosphere. However, the same 2019 Nature study discussed above implies that due to the slow development of silica cell walls induced by exposure to ocean acidification, the ability of diatoms to transport CO2 to the ocean’s depths might be negatively affected. Without the carbon sequestration services of diatoms, global warming could accelerate and may cause larger ecological problems, including worsening ocean acidification.  

The Importance of Diatoms

Despite their microscopic size, diatoms play a massive global role in making marine and terrestrial ecosystems habitable for both people and wildlife. However, the threat of ocean acidification may put diatoms under new stressors that might affect the services they provide. Here are some of the ways diatoms are important to ecosystems and people.

The Importance of Diatoms to the Ecosystem

Primary Food Provider

Diatoms are at the bottom of the food chain. They serve as food to larger organisms like zooplankton, krill, algae eater fishes, snails, and more. These larger organisms flourish because of the abundance of diatoms. Even larger marine animals depend on the organisms that rely on diatoms. For example, the whale’s primary diet is krill. Without diatoms, krill would not be able to survive. If there are not enough krill to sustain the whales, it could cause starvation and ultimately decline in whale populations. 

This hypothetical breakdown of the food chain shows the importance of diatoms as the primary food source in the food chain. Any damages to diatoms caused by catastrophic events such as ocean acidification would have a significant impact on all species who rely on their services, from the smallest krill to the largest mammal on the planet.

Read more: How Are Whales Affected by Ocean Acidification?

Natural Carbon Sink 

Diatoms are considered a natural carbon sink, as they absorb up to 20 billion tons of atmospheric carbon annually. Diatoms convert atmospheric carbon into organic carbon as they absorb it through photosynthesis. When they die, they carry the stored carbon down as they sink to the ocean floor. This carbon-absorbing ability has a significant impact on mitigating global warming and climate change.

diatoms carbon cycle - diatoms ocean acidification
Diatoms carbon cycle
Source: Frontiers in Plant Science

The Importance of Diatoms to People

Major Oxygen Supplier 

Since diatoms photosynthesize, they contribute significantly to the world’s supply of oxygen. In fact, according to the most recent data, diatoms are responsible for 25% of the global oxygen supply. Without diatoms, all species that rely on oxygen, including humans, may suffer from negative health complications due to lower oxygen supply.

Supplier of Bio-Products

Diatoms not only supply oxygen but they can also be utilized in creating bio-products, products made from natural, renewable materials. According to a recent study, diatoms can produce sustainably manufactured bio-products that could be used as pharmaceuticals that benefit people. This includes the following products: 

diatoms microscopic image - diatoms ocean acidification
Microscopic view of diatoms
Source: Diatoms.org

Diatoms can help humans in a variety of ways, including those mentioned above, and there may be many more benefits that science has yet to uncover. We already know how diatoms are affected by ocean acidification, which might alter the services they provide. It is critical to guarantee that these microorganisms continue to thrive, as without them, the Earth may become uninhabitable for humans and other species.

How Are Clams Affected by Ocean Acidification?

Posted on by Team Writer

Ocean acidification occurs when the pH level of seawater decreases, which is most frequently caused by the ocean absorbing excess CO2 from the atmosphere. Ocean acidification has negative effects on a variety of ocean ecosystems and life forms, including clams.

This article will explain how clams are affected by ocean acidification, as well as the importance of clams to ecosystems, people, and the economy.

Background information: Ocean Acidification Infographic

Table of Contents

How Are Clams Affected by Ocean Acidification?

The Importance of Clams

The Importance of Clams to the Ecosystem

The Importance of Clams to People and the Economy

How Are Clams Affected by Ocean Acidification?

Clams and other shell-forming marine species are particularly vulnerable to ocean acidification. As rising acidity in seawater reduces the number of carbonate ions, shell-forming organisms like clams don’t have enough carbonate to build their shells. Here are some of the negative effects of ocean acidification on clams.

Thinner Shells 

Hard and healthy clam shells are made from the combination of carbonate ions and calcium ions (both naturally present in seawater). When ocean acidification increases, the amount of available carbonate ions decreases. As a result of ocean acidification, clams have fewer resources to develop or reconstruct their shells, causing them to become thinner over time. According to research, the thickness of clamshells significantly reduces after only 3 months of exposure to acidic seawater.

Smaller Clams

Based on the result of an experiment in 2010, juvenile clams that are exposed to acidic water don’t grow as large. In acidic water, clams have less carbonate to develop their shells, so they adjust to the low availability of their environment by using less carbonate, and thus not growing as large.

clam ocean acidification reduces size
Experiment shows how ocean acidification reduces the size of clams
Source: Global Change

Increase in Mortality Rate

The negative effects of ocean acidification on clams don’t stop at the shell’s durability and growth. According to research, clams that are exposed to ocean acidification show an increase in mortality rate after 6 months. If ocean acidification continues to rise, this will pose a serious threat to the ecological balance of marine ecosystems and the people who rely on shellfish – particularly clams, in the aquaculture industry, which covers 38% of production globally.

The Importance of Clams

Clams play an unexpectedly important role in maintaining a healthy ocean ecosystem and provide products that benefit both marine life and people. However, the increasing threat of ocean acidification puts the important services that clams provide at risk. Here are some of the ways clams are important to ecosystems and people.

The Importance of Clams to the Ecosystem

Seawater Filtration

Considered filter feeders, clams filter seawater through their respiration and feeding process. The water flows into the clam through their cilia, and all the particles that are pulled in are trapped by their gills and transferred to their mouth to feed, while the filtered seawater is released back into the ocean. This filter-feeding activity contributes to maintaining the ocean’s water quality.

Here is an example of an experiment conducted by the University of Florida/IFAS that demonstrates the efficiency of clams in water filtration:

Ocean Nitrogen Remover

Clams accumulate nitrogen by filtering water and feeding on phytoplankton, which are rich in nitrogen. When clams are removed from the ocean, nitrogen is also removed. Through shellfish culturing and farming, clams can be utilized in nutrient bioextraction, the removal of nitrogen from the seas. This can help create the right balance of nutrients in the ecosystem. Clam’s nitrogen uptake can also help bodies of water prevent excessive algae growth that often results from too much nitrogen in the water.

Natural Nutrient Cycling 

Clams cycle nutrients within an ecosystem, which help other plants and animals thrive. After digestion, clams distribute nutrients through their nitrogen-rich urine and fecal deposits that fertilize various types of marine plants such as kelp.  Other marine species such as krill, sea urchins, and crabs rely on these nitrogen-fertilized plants for food.

Carbon Sequestration

Clams are also considered a carbon sink because they utilize carbon to produce calcium carbonate to develop their shells. This contributes to the sequestration of dissolved atmospheric CO2 , which can help take carbon out of the atmosphere. This in turn can help reduce climate change and ocean acidification. 

If the ocean continues to acidify, we might lose a great number of clams and other shellfish populations. Without the services that clams provide, the ocean may face an ecological imbalance that would affect many marine species. 

The Importance of Clams to People and the Economy

How Clams Benefit Aquaculture and the Tourism Industry 

Shellfish farming, including clam farming, is very common in coastal areas. Many people that are living in these areas rely on clams as a main source of income. For example, in 2014, the clam farming sector in Washington County, Maine employed around 640 individuals. Clamming generates many economic advantages, such as clamming-related employment possibilities, the chance to expand tourism through the clam business, and tax revenue to strengthen various programs and services.

clam sanctuary and diver - clams ocean acidification
Giant clam sanctuary promoting ecotourism in the Philippines
Source: Froirivera/Wikimedia

Another example of clams’ benefits to the economy is giant clam ecotourism in Samal Island, Philippines. Today, local communities on the island, as well as resort owners, are collaborating to protect giant clam species, which increases tourism and creates new employment opportunities for seniors and women on the island. Clam tourism also generates revenue to improve community programs and services. 

With higher mortality rates, smaller sizes, and poor clam quality, the clam aquaculture and tourism sector as a whole may suffer due to ocean acidification. These negative consequences of ocean acidification on clams may harm people who rely on clams for a living, as well as the local economy that majorly depends on the clam industry.

Health Benefits from Clams in the Diet

Eating clams provides more than great flavor, as clams also provide seafood eaters with various health benefits and nutrients. Here are some examples: 

  • Clams are rich in vitamin b12, zinc, and iron, nutrients that are important in boosting the immune system.
  • Clams also provide collagen, which is important for our joints, skin, and bones. 
  • Clams contain iodine, which is important to thyroid hormone production in our body. 
  • Just like any other fish, clams are rich in omega 3 fatty acids. This fatty acid is great for maintaining a healthy heart.
  • Clams are a good source of choline. This nutrient is essential for liver protection against diseases such as the fatty liver. A study also suggests that choline could prevent or lower the risk of having Alzheimer’s disease. 
  • Clams are rich in selenium, which can increase male fertility. A study found that consuming shellfish like clams improves sperm motility.

However, research has found that clams’ exposure to ocean acidification significantly increased the amount of cobalt that clams absorb. This could be toxic to people who eat clams and may put their health at risk if the cobalt is highly concentrated. This is an indication that if ocean acidification continues, it could negatively impact not only the shellfish industry, but also human health.

How Several Marine Species Are Coping with Ocean Acidification

Posted on by Team Writer

fish and coral - ocean acidification adaptation

Different types of marine life in Hawaii, such as several reef fish species and corals, are showing resilience to rising ocean acidity. 

  1. Several reef fish species are evolving to adapt to increasing ocean acidification. (more…)
  1. Some coral species in Hawaii are showing resilience to ocean acidification and warming. (more…)

Background Information: Ocean Acidification Infographic

Full Report: Certain Fish Species Are Rapidly Evolving to Adapt With Ocean Acidification; Hawaiian corals show surprising resilience to warming oceans

Several Reef Fish Species Are Adapting to Ocean Acidification

A recent study suggests that some fish species may be able to adapt to ocean acidification by developing more flexible features. Here’s what you need to know about it: 

  • The study focused on six common reef fishes to see how they respond to ocean acidification. They included factors such as the frequency of their activities and their parental care.
  • In Papua New Guinea, six adult coral reef fish species were studied for their cellular reactions to high CO2 levels in their brains after being exposed to various amounts of greenhouse gases.
  • The results of the study revealed that the elevated CO2  levels in the fish’s brains affected their immune systems and circadian rhythms, which play a huge role in the fish’s metabolism and sleep patterns.
  • When exposed to elevated CO2, the circadian genes triggered changes in other genes in the brain, allowing the fish to adapt to increasing ocean acidification.
  • The researchers also revealed that the immune system’s reaction to high CO2 levels was a critical component of reef fish adaptation to ocean acidification. It was remarkable, however, that certain nocturnal species’ immunity genes enhanced when exposed to CO2, whereas other species’ immunity genes were dominated by high CO2 levels.

Several Coral Species in Hawaii Are Showing Resilience Against Ocean Acidification

A new study shows new hope regarding the ability of Hawaiian coral species to cope with ocean acidification and ocean warming. Here’s all you need to know about the study:

  • The coral samples were placed in different tanks that replicated the natural conditions of coral reefs. These tanks allow the scientists to observe the varying temperatures and pH levels during different times of the day.
  • These tanks contained four different conditions, including: 
    • Tank with current ocean condition
    • Tank with an ocean acidification condition
    • Tank with an ocean warming condition
    • Tank with both ocean acidification and warming conditions
  • Researchers discovered that some coral species died after being subjected to conditions that simulated ocean temperatures and acidity levels. However, not all of the coral species studied died, In fact, some of them were still alive and even flourishing after the experiment.
  • Over the duration of the study, the Porites compressa and Porites lobata show more resiliency than Montipora capitata.
  • The results of the study revealed that the Porites species exhibited resilience to acidification and warming. These corals can play a critical role in the redevelopment of coral reefs during climate change since these species are one of the most common around the world.
reef species ocean acidification adaptation
The view of the experimental tank under climate change conditions after 22 months of the experiment.
(Source: © Rowan McLachlan/Ohio State News) 

Sources: 

“Certain Fish Species Are Rapidly Evolving to Adapt With Ocean Acidification” Nature World News, March 04, 2022

https://www.natureworldnews.com/articles/49735/20220304/certain-fish-species-rapidly-evolving-adapt-ocean-acidification.htm

“Hawaiian corals show surprising resilience to warming oceans” Science Daily, March 10, 2022

https://www.sciencedaily.com/releases/2022/03/220310115150.htm

Researchers Propose Controlling Ocean Acidity to Lower Carbon Dioxide in the Atmosphere

Posted on by Team Writer

Recent research published in Energy and Environmental Science suggests a new potential method for relocating surface seawater acidity into the depths of the ocean, which will not only help fight ocean acidification on the surface but will also allow the ocean to capture more CO2 from the atmosphere. This has the potential to help fight climate change, caused by high levels of carbon in the atmosphere. Here are the study’s main takeaways:

  1. The research was authored by Google employees Mike Tyka, Researcher in Computational Biophysics and Biochemistry, John Platt, Director of Applied Science, and Christopher Van Arsdale, Climate and Energy R&D. 
  1. The proposal to pump surface acidity to the deep ocean would stabilize ocean acidification, thus amplifying the ocean’s ability to capture CO2 from the atmosphere without increasing ocean acidification. (more…)
  1. The proposed project’s simulation method demands two primary requirements, seawater and energy. (more…)
  1. The cost for the proposed project is estimated to be cheaper than other existing CO2 removal methods. (more…)

Background Information: Ocean Acidification Infographic: What Is Ocean Acidification?

Full Research Paper: CO2 Capture By Pumping Surface Acidity To The Deep Ocean

Stabilizing Acidification And Increasing The Ocean’s Co2 Capture

The researchers propose a mechanism designed to accelerate the downward movement of acidity from the top of the ocean to its depths. Researchers argue that moving acidity to the depths of the ocean mirrors the natural biological carbon pump, and allows carbon to be stored in the deep ocean. This, in turn, would decrease surface acidity (helping to control ocean acidification) and allow the ocean to absorb an increased amount of carbon dioxide from the atmosphere.,  Here’s how they plan to do it:

  • Through a pumping process, the alkaline discharge or the base would be transported up to the surface water, and the acidic water from the surface would be transported deep down into the ocean floor. This increases the alkaline level on the surface water and regulates the acidity or pH level. 
  • It’s estimated that during a 50-year span of utilizing the proposed method, approximately 3 gigatons of carbon suspended in the atmosphere could be eliminated, and it would only lower the deepwater acidity level by 0.2.
  • With regulated surface water pH levels, coral reefs and other shell-forming marine animals will thrive, as these are the species that are most damaged or affected by ocean acidification.

How Will This Work? Requirements and Process of Acidity Pumping

The proposed project’s method demands two primary requirements for the process to function.

Seawater

⮚   One of the primary requirements of the proposed project is seawater. It is critical since it is the primary focus of the research, and may also be utilized as a source of energy.

Energy

⮚   Another primary requirement is energy, as it is essential for any mechanism to function. The energy needed could be generated through waves that come from the open ocean, wind energy that can be harnessed offshore, or ocean thermal energy conversion, where energy is generated through temperature variations in ocean waters.

Process

⮚   Through electrochemical pumping, the saltwater will be separated into acid and base. After this separation process, the acidic water will be released into the depths of the ocean, and the base which will be released in the surface water, which will stabilize the pH level, allowing the ocean to capture more carbon in the atmosphere. Acidity on the ocean floor will accelerate the breakdown of alkaline sediments on the ocean floor, thereby reducing acidity.

The image below illustrates how the pumping of acidity from surface water would accelerate the natural weathering of sedimentary carbonates on the ocean floor. Through this proposed process, carbon is stored in ocean depths and alkaline carbonate deposits dissolve (both of which reduce acidity), while carbon dioxide uptake is increased at the surface.

ocean acidification infographic - carbon pumping
Source: Tyka et al. 2022

The Cost of Surface Acidity Pumping Is Estimated To Be Cheaper Than Other Methods

The proposed project estimate cost per ton of captured CO2 appears to be less expensive than other existing CO2 removal methods. Below are the following estimates for each method: 

⮚   Pumping surface acidity to the deep ocean is anticipated to cost $93–$297 for each ton of CO2 captured by the proposed project.

⮚   Another method of removing carbon is called CO2 extraction, which is estimated to cost $373–$604 for every ton of CO2 captured.

⮚   Direct air capture of carbon is estimated to cost $89–$506 per ton of CO2captured.

⮚   The terrestrial weathering method is estimated to cost $24–$578 per ton of CO2captured.

Sources: 

“CO2 capture by pumping surface acidity to the deep ocean” Energy & Environmental Science, February 2022

https://pubs.rsc.org/en/content/articlelanding/2022/EE/d1ee01532j#cit13