The research paper “Severe 21st-century ocean acidification in Antarctic Marine Protected Areas” by Cara Nissen et al., focuses on the future of ocean acidification (OA) in Antarctic Marine Protected Areas (MPAs) under different emission scenarios using a high-resolution ocean-sea ice-biogeochemistry model. The study highlights severe potential declines in pH and the consequences for marine biodiversity.
Map of Marine Protected Areas and Impacted Species
About This Map
This map of Antarctica featured in the study illustrates the locations of established and proposed Marine Protected Areas (MPAs) around the continent. It also highlights key marine species that may be negatively impacted by ocean acidification, with their positions around the map representing their typical habitats within these MPAs.
Key Takeaways:
Antarctic Vulnerability: Antarctic coastal waters, including several MPAs, are under threat from ocean acidification due to increased anthropogenic carbon uptake. These waters support exceptional biodiversity, making them critical to preserve.
Emission Scenarios and OA Projections: The study examines four emission scenarios, projecting significant pH declines by 2100, with the highest reductions under high-emission scenarios. This results in widespread aragonite undersaturation, affecting marine organisms that rely on calcium carbonate structures.
Biogeochemical Changes: Antarctic waters are highly sensitive to OA due to cold temperatures and upwelling of carbon-rich deep waters. The study highlights the enhanced vertical mixing of anthropogenic carbon on continental shelves, exacerbating local OA.
Impact on Marine Life: Various marine organisms, including primary producers and shell-forming species, are expected to face severe impacts from OA. The study notes potential declines in populations and shifts in community structures due to altered physiological processes and ecosystem dynamics.
Conservation Implications: The research supports the expansion of MPAs as a strategy to mitigate OA impacts and preserve marine biodiversity. It calls for strong emission-reduction efforts and enhanced management strategies to alleviate pressures on these ecosystems.
Modeling Approach: Utilizes a sophisticated modeling approach that integrates realistic ice-shelf geometry and high-resolution data, providing detailed projections that highlight the urgent need for climate action to protect Antarctic marine environments.
The Great Barrier Reef, located off the Australian coast, is the largest coral reef ecosystem on the planet and one of the most outstanding world heritage sites. It serves as a vast sanctuary for thousands of marine species, protects surrounding islands from storms, provides food, and generates revenue through ecotourism. But the Great Barrier Reef is now in great danger as it experiences its sixth massive coral bleaching event.
A new report from UNESCO scientists explains that the Great Barrier Reef is suffering from accelerating damages from human-caused climate change. They argue that the area must be listed in the record of world heritage sites as “in danger” because the deterioration is accelerating at an alarming phase, pushing the reef’s health beyond its tipping point.
In this article, we’ll review the main points of the new UNESCO report on the Great Barrier Reef and explore the global response to the report.
Since 2015, the Great Barrier Reef has been experiencing massive coral bleaching events due to increasing ocean temperatures and ocean acidification. In fact, in 2021, scientists discovered that the global population of living corals has declined by 50% since the 1950s. This is due in large part to the ongoing usage of fossil fuels such as coal, oil, and gas around the world.
Recent UNESCO scientists’ assessments of the Great Barrier Reef found that it is experiencing its sixth massive coral bleaching event, pushing the reef’s damage to an irreversible tipping point.
During their monitoring, scientists discovered around 750 out of 3,000 reefs within the Great Barrier Reef are suffering from widespread bleaching. That is about 25% of the Great Barrier Reef.
James Cook University marine biology professor Jodie Rummer explains that even the healthiest coral may take a decade to recover from bleaching, and with consecutive mass coral bleaching events, we may not see adaptation and recovery as an option for them.
Scientists predicted that up to 90% of coral reefs around the world may disappear in the next 20 years due to ocean acidification. The Great Barrier Reef is one of the reef areas most affected by acidification.
UNESCO scientists’ report argues that the Great Barrier Reef should be added to the list of world heritage sites that are “in danger.” This UN-backed recommendation comes after the World Heritage Committee’s initial recommendation of an “in danger” listing in 2021.
The report argues that in order to give the Great Barrier Reef a chance to combat the effects of ocean acidification, we must reduce greenhouse gas emissions, reassess carbon credit schemes and increase financial investment in protecting the reef.
What Was the Response to the UNESCO Report?
UNESCO’s push to list the Great Barrier Reef as “in danger” was received with a mixed response.
UNESCO advised the Australian government to boost its carbon-reduction policies and invest more in water-quality improvement programs. However, the Australian government’s policies continue to fall short of UNESCO’s critical recommendations.
The Australian government argues that it is unnecessary to list the Great Barrier Reef as “in danger” because they are doing enough to protect the Great Barrier Reef. For example, they cite their recent commitment to invest $1 billion in reef protection programs from 2022 to 2030.
While UNESCO acknowledges that listing the Great Barrier Reef as “in danger” could affect its tourism, it may also establish Australia’s name as a world leader in terms of the conservation and protection of a world heritage site.
UNESCO also emphasized that categorizing the Great Barrier Reef as “in danger” on the world heritage list is essential, as it could encourage other countries to join in conservation efforts to protect it. The World Heritage Committee’s decision whether to label the Great Barrier Reef as “in danger” or not will be based on UNESCO’s assessment. UNESCO is still waiting for Australia to ensure compliance with their provided recommendations. However, the Australian government continues to deny that these recommendations are necessary.
“Report on the Joint World Heritage Centre/IUCN reactive monitoring mission to the Great Barrier Reef (Australia from 21 to 30 March 2022)” UNESCO, Nov 2022.
Increases in ocean acidity are damaging the first link in the food chain, a microorganism called coccolithophores. This is causing major impacts to marine species that rely on coccolithophores as their primary source of food.
Recent research from the Universitat Autonoma de Barcelona’s Institute of Environmental Science and Technology illustrates how ocean acidification is affecting coccolithophores, and thus, how ocean acidification is affecting the food chain as a whole.
Coccolithophores, part of the phytoplankton family, are single-celled plant-like marine microorganisms that are commonly found close to the surface of the ocean. Despite their microscopic size, coccolithophores play an important role in the marine food chain by serving as its foundation. Many small marine animals rely on coccolithophores as their primary source of food and energy. Even small fish and other organisms that do eat other things, like worms or small crustaceans, feed on coccolithophores when other sources of food are scarce. Marine animals obtain nutrition and energy from coccolithophores’ fat content, known as lipids.
Coccolithophores build protective scale-like platings around themselves known as coccoliths (the oval platings shown in the image to the right). These coccoliths are made of limestone (calcite). However, ocean acidification makes it much more difficult for organisms to build calcite shells.
A 2022 study conducted by researchers from the Universitat Autonoma de Barcelona’s Institute of Environmental Science and Technology, in collaboration with the Roscoff Marine Station of France, discovered that ocean acidification has significantly reduced coccolithophores’ ability to build shells, and decreased the nutrient content in their bodies. This has massive cascading effects throughout the food chain. Here’s what you need to know about it.
The researchers created a simulation of future climate conditions, causing ocean warming and triggering ocean acidification.
At first, the coccolithophores showed resilience to the increase of ocean temperatures and acidity. The researchers even observed an increase in their population.
As the experimental ocean acidity spiked, the researchers found that coccolithophore population growth halted as the organisms began to struggle to build their shells. The acidic conditions caused the coccolithophores’ protective platings (coccoliths) to collapse. While this may seem beneficial to organisms that eat coccolithophores (because this makes them easier to eat and digest), this breakdown of their shells comes with other negative consequences.
Researchers also discovered that when coccolithophores were exposed to acidified ocean conditions, the nutritional content in their bodies significantly decreased. As acidification worsens, this reduced nutrient content may have a detrimental impact on the food chain. Marine species that rely on coccolithophores for food, such as smaller fishes and zooplanktons, would be forced to feed on nutritionally deficient food.
Researchers concluded that as ocean acidification affects coccolithophores’ energy and nutrients, coccolithophores may also seek lower-acidity areas to try and slow ocean acidifications’ effects on their survival. This movement will pose an extra threat to marine species that rely on coccolithophores for food, as some may be unable to “follow” coccolithophores to lower-acidity conditions..
The images below show the comparison of healthy coccolithophores (a) and collapsed coccolithophores due to ocean acidification (b).
As climate change-driven ocean acidification and higher ocean temperatures continue to threaten various marine animals, some species are beginning to evolve in order to adapt to warmer, more acidic conditions. But does this evolution come at a price? A recent experiment from the University of Vermont, in collaboration with the University of Connecticut, the GEOMAR Helmholtz Center for Ocean Research in Germany, and the University of Colorado, Boulder, focuses on this question.
This March 2022 study analyzed how one copepod (a small crustacean species), Acartia tonsa, will likely evolve in order to adapt to warmer ocean temperatures and higher levels of carbon dioxide. However, these copepods’ resilience to climate change comes hand in hand with increased vulnerability to other stresses such as limited food sources.
Scientists from the University of Vermont conducted a laboratory experiment to understand the effects of ocean acidification on copepods, a group of small crustacean species that serve as a food source for many marine species. Copepods also act as an important biological control agent against mosquitos carrying human diseases.
Researchers artificially evolved 23 generations of Acartia tonsa, a copepod species, in order to study the effects of ocean acidification on copepod reproductive success. The results reveal that copepods can adapt fairly quickly to a warmer, acidified ocean ecosystem, but that this rapid evolution decreases the species’ genetic flexibility, which leads to increased vulnerability to other stresses.
Finding One:Copepods have the ability to quickly adapt to ocean acidification due to high genetic flexibility.
Copepods have the ability to become sexually mature and reproduce in just four to six weeks, making them a helpful organism to help scientists study evolution over shorter periods of time. This study utilizes copepods’ ability to reproduce and create new generations in a short period of time to analyze the effect of ocean acidification and warming on the health and reproductive success of twenty-three generations of copepods.
Scientists created an ecosystem that simulates future ocean conditions under climate change. They exposed thousands of copepods in multiple generations to the acidic environment and tracked their health and reproductive ability.
The study found that copepods showed resistance to ocean acidification and continued to thrive throughout twenty-three generations. This is due to copepods’ plasticity (genetic flexibility), or the ability to manipulate their genes, allowing them to adapt to environmental changes. This includes but is not limited to:
Ability to adapt to increasing temperatures in their environment
Ability to grow skeletons in an acidified environment
Ability to generate additional energy in order to adapt to the stress caused by ocean acidification.
Although the results provide optimism for the future of copepod populations, the next experiment demonstrates the cost of this generational adaptability to copepods’ health and reproduction.
Finding Two: Rapid evolution in order to evolve to ocean acidification decreases copepods’ ability to adapt to other environmental stressors in the future.
After twenty-three generations of copepods living in an acidified environment, scientists reintroduced some of the copepods in the less acidic environment – the current acidity level of the ocean today. The new generations of copepods that were reintroduced to this less acidic environment did re-adapt to these new conditions – but with lowered ability to respond to other kinds of stressors like a limited food supply.
The researchers explained that, in an effort to adapt quickly to acidified conditions, the copepods lost genetic flexibility (known as “phenotypic plasticity”), their ability to genetically adapt to different environmental conditions.
The copepods genetically adapted to high acidity conditions, which left them all with similar genetic makeup. This left them less able to adapt to new stressors, such as a lowered food supply. Copepods in the lower-acidity environment their ancestors had come from had smaller populations and were generally less healthy.
The scientists concluded that, while there is hope for copepods and other ocean animals to adapt to increased ocean acidity and warming ocean, there may be hidden costs for those species as a result of rapid evolution.
Brennan et al. “Loss of transcriptional plasticity but sustained adaptive capacity after adaptation to global change conditions in a marine copepod.” Nature, March 3, 2022, DOI: 10.1038/s41467-022-28742-6.
Rising ocean acidity is threatening the population of the most common type of plankton, known as diatoms, one of the main oxygen producers on the planet and the primary food source for all marine life. Despite previous beliefs that diatoms actually benefit from ocean acidification, new research from the Helmholtz Centre for Ocean Research (GEOMAR) shows that diatom populations are extremely vulnerable to the effects of ocean acidification. Continue reading for a summary of the paper’s findings.
How Ocean Acidification Reduces Diatom Populations
In past years, scientists believed that diatoms are less affected than other marine organisms by the effects of ocean acidification. This was because diatoms rely on silica minerals to build their shells, rather than calcium carbonate, a substance that many other marine organisms rely on to build their shells and that is reduced by ocean acidification. In fact, some scientists previously argued that ocean acidification aids diatoms by increasing their ability to photosynthesize, and thus increasing diatom populations’ growth.
But, in a recent analysis, scientists explain how ocean acidification may reduce the population of diatoms at an alarming rate. Here’s what you need to know about it.
The study researched the effects of ocean acidification on the dissolution of the silicon shell of diatoms. The results show that acidified seawater significantly slowed the ability of diatoms to dissolve their silicon shells, ultimately leading to a lowered ability to gain nutrients through photosynthesis.
The most common negative impact of ocean acidification on shell-forming marine species using calcium carbonates, such as oysters, clams, mussels, and corals, is a reduction in their capacity to form shells due to a lack of carbonate ions in more acidified seawater. While this chemical imbalance was not believed to affect diatoms due to their silicon-based shells, ocean acidification actually threatens diatoms in another way.
GEOMAR Helmholtz Centre for Ocean Research Kiel researchers used data from huge test tubes known as Mesocosms. These tubes were placed in different ocean biomes all around the world. Mesocosms can contain a large volume of ocean water inside, allowing researchers to manipulate the water parameters, such as increasing or decreasing the acidity level without harming the ocean ecosystem outside.
Using an Earth system model, the researchers utilized the collected data to simulate the negative effects of ocean acidification on diatoms in the future, on a worldwide scale.
Researchers discovered that acidified seawater slows the ability of diatoms to dissolve their silicon shells, which forces them to sink into the deeper parts of the ocean. Because of this, the abundance of diatoms on the ocean surface is lowered.
Researchers concluded that since diatoms needed to be at the surface water to get light to renew their shells, forcing them to sink may significantly decrease their population around the world at an alarming rate.
Rising ocean acidity is affecting the development of different types of marine species, such as sea urchins and brightly-colored reef fish.
A recent study shows how sea urchin development is affected by ocean acidification. (more…)
The Great Barrier Reef is experiencing massive coral bleaching events due to ocean acidification, which negatively affects the development of brightly-colored fish in the reef. (more…)
Study Shows How Ocean Acidification Affects Sea Urchin Early Stage Development
Ocean acidification has a significant negative impact on marine species and ecosystems. A recent study shows how ocean acidification affects the early development stages of some marine species, such as sea urchins. Here’s what you need to know about it.
The study researched the effects of pH on sea urchin’s development and transition from fertilization to juveniles. The result shows that low pH levels significantly affected the growth and mortality of the urchin’s larval stage. Even small changes in ocean pH (on the scale of .1) can have major impacts.
Larval Stage: Effects of Ocean Acidification
Sea urchin larvae were exposed to a 7.2 pH level (compared to the current ocean’s actual pH of 8.1). The sea urchins exposed to this pH exhibited the following characteristics:
Higher mortality rates.
Higher abnormality rates.
Lower growth rates.
The metabolism of sea urchin larvae exposed to a 7.2 pH level increased as well. The researchers believe that because of this, the urchins may be using additional energy to boost metabolic function, which might limit their growth rates. In other words, the sea urchins adapt to ocean acidification by shifting their energy to boost metabolic function, rather than other important functionalities. Researchers believe that this shift in energy may be what’s causing mortality and abnormalities throughout their development stages.
Settlement Stage
Researchers discovered that prolonged exposure to a 7.7 pH level significantly delayed the settlement of sea urchin larvae, an important process during which larvae settle to the ocean floor where they will eventually begin their adult life stages.
However, when the sea urchin larvae were placed under a suitable algal substrate for the settlement stage, the researchers found that the larvae remained unaffected by 7.7 pH levels. This shows that algae may help reduce the effects of ocean acidification on sea urchin larvae.
Metamorphosis Stage
The study shows that in the metamorphosis stage, all the sea urchins that were grown at a 7.2 pH level failed to metamorphose. The researchers concluded that sea urchins that are exposed to low pH levels throughout their early development stages may find it hard to impossible to achieve metamorphosis.
However, the study also shows that 30% of the sea urchin larvae that were grown at a 7.6 pH level achieved the metamorphosis stage. This shows the large impact of even a pH change of .4, compared to the 7.2 pH group of urchins.
Ocean Acidification Affects Brightly-Colored Fish Development Through Continuous Coral Bleaching
The Great Barrier Reef is experiencing massive coral bleaching events due to ocean acidification, which negatively affects the development of fish’s color in the reef. Here’s all you need to know about the study.
In the span of just three decades, the effects of ocean acidification and global warming have caused the Great Barrier Reef to lose thousands of its coral species. This phenomenon is commonly known as massive coral bleaching events. As a result of this, the number of brightly-colored fish in the Great Barrier Reef is decreasing.
According to the study, the number of different types of brightly-colored fish in the Great Barrier Reef has declined significantly since the massive coral bleaching event of 1998. Scientists believe that the composition of the seafloor (texture, colors, patterns) affects the development of the coloration of fish.
Reef fishes developed coloration to protect themselves from predators by adapting to the different coral structures and compositions. Fish would find it useless to produce vibrant colorations in the absence of coral compositions.
The study concluded that the loss of vibrant composition and structure of the seafloor due to the massive coral bleaching events has a significant relationship to the inability of many fish to develop their vibrant colors.
Ocean acidification occurs when the pH level of seawater decreases. This is most frequently caused by the ocean absorbing excess CO2 from the atmosphere. By evaluating an ocean acidification case study, we can get a sense of how damaging ocean acidification currently is, and what measures can be implemented to prevent further damage.
This article will outline a case study on how ocean acidification affects coral reefs in the Pacific Basin, as well as proposed solutions to prevent further damage.
This study, Lebrec et al. 2019, was originally published in the journal “Regional Studies in Marine Science.” It discusses the effects of ocean acidification on coral reefs in the Pacific Basin, where mass coral bleaching has occurred. The case study highlights five coral reef ecosystems in the Pacific basin, which are found in the following locations:
Ryukyu Archipelago, Japan
Palau
Hawaii
Marshall Islands
American Samoa
Locations of coral reef ecosystems highlighted for the case study Source: Lebrec et al. 2019
The case study evaluates the impact of ocean acidification on the above locations and proposes solutions to prevent ocean acidification and other ocean stressors from causing further damage to coral reefs.
Ocean acidification negatively affects the coral reefs in the Pacific Basin by reducing the amount of calcium carbonate that is essential to coral reef skeletal development and coral survival. This causes coral reef death.
The study highlights the importance of unique coral diversity in each of the five geographic locations, as well as the vital role coral reefs play in local communities and economies.
Hawaiian coral reefs are not just important to the tourism industry, but they also provide direct benefits to the community by sustaining fisheries and pharmaceutical production, which generate income through exportations. Hawaiian coral reefs also provide indirect benefits to the community by protecting coastal areas from storms. The economic value of coral reefs in Hawaii is about $455 million USD.
The Marshall Islands is the world’s most coral reef-dependent country. Most of their needs are met by the reef, including employment, nutrition, exportation, tourism, and protection against natural disasters.
The Ryukyu Archipelago is home to more than 360 species of corals, which makes it the world’s richest endemic coral reef. The archipelago’s coral reef plays an important role in its economy, generating $4.7 billion USD tourism revenue in a single year.
Palau is home to around 425 species of coral reef, which makes the country the most biodiverse coral reef in all of Micronesia. It provides 40% of the country’s employment, as over 90% of tourists that visit the island come for diving and snorkeling.
American Samoa is home to about 200 coral reef species, which is why the government established 6 major protected areas for coral reefs across the archipelago.
The locations in the case study are experiencing coral bleaching events due to the combined effects of different disasters, pollution, and ocean acidification. This affects these countries since all of them rely heavily on the services that coral reefs provide.
Hawaiian coral reefs are bleaching as a result of rising temperatures and ocean acidification, and certain coral reef species are recovering at a slower rate than expected.
Increasing temperatures have bleached over 90% of the coral reefs of Okinawa Island, which is part of the Ryukyu archipelago.
From 1997 to 1998, Palau had a GDP decline of about 3.3% due to intense coral bleaching events.
Coral reef bleaching in Airport reef, Tutuila, American Samoa Source: Coral Reef Watch/NOAA
Proposed Solutions to Fight Ocean Acidification-Related Bleaching
This case study provides 3 proposed solutions to fight ocean acidification and its damage to the coral reefs in the Pacific basin.
Adaptation promotes the resilience of coral reefs by initiating conservation regulations and the reforestation of coral reefs, and increasing coral reef protected areas.
Mitigation covers the reduction of carbon emissions at the global and local scales. This could be in the form of carbon taxation, an emissions trading system, or a cap-and-trade system.
Capacity Building focuses on promoting local research advancements and spreading education and awareness to the community, generating funds to improve coral reef conservation efforts, and creating local collaborative efforts to promote national policies that push for unified international policies.
Conclusions
This case study highlights the importance of coral reefs in the Pacific Basin and how the countries around it majorly depend on the services that the coral reefs provide. Understanding the impacts of ocean acidification on coral reefs in the Pacific basin can help us promote solutions to ensure their benefits to humans and ecosystems remain intact.
This case study is just a part of a much larger global issue of ocean acidification and its negative effects. There are many other countries around the world that are experiencing not only coral reef bleaching but also damage to marine animals and microorganisms that are essential to maintaining the ecological balance of the world. The case study emphasizes the importance of addressing ocean acidification, as if we fail, people all over the world will lose sources of food, income, and culture.
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.
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 anocean 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.
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.
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.
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:
Longer than most of its comparable studies, This research spanned 22 months. It started with the collection of samples from three Hawaiian coral species, such as Montipora capitata, Porites compressa, andPorites lobata.
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.
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:
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.
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…)
The proposed project’s simulation method demands two primary requirements, seawater and energy. (more…)
The cost for the proposed project is estimated to be cheaper than other existing CO2 removal methods. (more…)
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.
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
