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.
Did you know that the sunscreen you apply doesn’t always stay on your skin? In fact, when we swim (or even shower), the sunscreen you’ve applied throughout the day washes off into waterways and often ends up in the ocean. In fact, around 6000 tons of sunscreen washes off into reef areas every year, according to scientists. That’s equal to the weight of nearly 50 blue whales!
While we depend on sunscreen to protect us from skin damage and disease, many sunscreens actually cause great harm to marine ecosystems. And with 80% of corals in the Caribbean lost in the last 50 years, in part due to pollution, it’s more important now than ever before to ensure we take steps to avoid damaging these important organisms further.
But how exactly does sunscreen damage coral reefs, and what can we do about it? Let’s dive in.
Protection for People, Harm to Marine Life
Researchers estimate that approximately 10%, if not more, of coral reefs around the world are threatened by sunscreen. The areas feeling the brunt of the damage are highly-tourested areas like Hawaii and the Caribbean, where thousands of tourists swim every day, leaving sunscreen behind them.
So, how is sunscreen killing coral reefs? There are two main types of sunscreen: physical and chemical. Unfortunately, both types of sunscreen can cause harm to coral and other types of marine life.
Physical sunscreen is made of minerals that sit on top of your skin and reflect the sun’s rays. The main minerals used for this purpose are titanium dioxide and zinc oxide, which can wash off into the water. In fact, studies estimate that the average tourists on a Mediterranean beach release 4kg of titanium dioxide in a single day. When these minerals are very small (called “nanoparticles”), they can be absorbed by coral and cause severe damage.
A 2018 study found that zinc oxide nanoparticles cause extreme coral bleaching. This is because the zinc interferes with symbiosis between coral and other organisms, which leads to bleaching over time. Zinc oxide and titanium dioxide nanoparticles in the ocean may also cause chemical reactions to occur that result in hydrogen peroxide, which bleaches coral.
Chemical sunscreens contain chemicals that absorb into the skin, and then absorb UV rays before they can hit your skin. The active ingredients include “UV filtering” chemicals avobenzone, octinoxate, and oxybenzone. These are extremely potent and toxic to marine animals including coral.
New Research: How Does Sunscreen Harm Coral Reefs?
While scientists have known that oxybenzone damages coral reefs for a while, they did not know exactly how the chemical was causing harm. In May 2022, researchers at Stanford released a study that explored oxybenzone’s effects on sea anemone, an organism that’s closely related to corals.
The researchers found that when oxybenzone was exposed to light and a sugar found in anemone tissue, not only did it kill the anemone, but the chemical metabolized into another molecule, releasing free radicals that kill coral. Sea anemones exposed to oxybenzone and sunlight died around one-three weeks after exposure.
Finally, preservatives used in sunscreen to help the product last longer can also have toxic effects on both humans and coral. For example, parabens, a class of preservatives, are used in many sunscreens to prevent the growth of bacteria and mold. However, parabens can wash off into the environment, and have been found in a wide variety of organisms all over the world, from fish to marine mammals and birds. Studies show that parabens can disrupt the hormones of a variety of animals, including humans.
Parabens can also cause viral infections in zooxanthellae, symbiotic algae that live in healthy coral tissue and provide it with nutrients. A 2008 study showed that, because of these viral infections, coral bleaching occurred within a few hours to a few days of exposure to even very small amounts of sunscreen.
Does Sunscreen Harm Other Types of Ecosystems?
It’s not just marine life that’s impacted by sunscreen. When we shower, sunscreen is often washed off into wastewater, which makes its way into fresh bodies of water. However, due to the extreme variety of aquatic ecosystems throughout the world, the specific impacts of sunscreen in aquatic environments are still unknown.
Many experts are calling for more research into the impacts of sunscreen on non-marine ecosystems. In August 2022, the National Academies of Sciences, Engineering and Medicine published a report calling on the US EPA to conduct further studies into the risks that UV filters cause to aquatic ecosystems (including freshwater). They explain that while we know UV filters have been found in water, sediment and even animal tissue in a variety of ecosystems, we need more information to understand the extent of the impacts they’re having on a variety of aquatic organisms.
Government attention to the issue of sunscreen killing coral reefs is not limited to scientific data gathering, however. Next, we’ll review how a few governments have taken a stab at protecting coral reefs and other marine organisms from toxic sunscreen ingredients.
Legislation: Bans on Reef-Toxic Sunscreen
In response to concerns about the toxic effects of sunscreen on coral reefs and the intense reduction in living coral reefs, several governments have passed legislation banning sunscreen containing oxybenzone and octinoxate.
Hawaii was the first state to ban harmful sunscreens with the passage of a bill in 2018 that banned oxybenzone and octinoxate sunscreens. In 2021, the Hawaii State Legislature passed another bill that banned two more harmful chemicals in sunscreen, avobenzone and octocrylene.
Other local and federal governments have also banned harmful sunscreens, including:
What You Can Do to Protect the Ocean from Harmful Sunscreen
There are a few things you can do to avoid putting more harmful sunscreen into the ocean.
1. Use other forms of sun protection. While sunscreen is, of course, a necessary product to protect ourselves from harmful ultraviolet rays, it should really be a last resort. Instead, use UV-protective clothing like a sun shirt to reduce the amount of sun your skin is exposed to. You can also try and spend time in the shade to protect your skin.
2. Use reef-safe sunscreen. When you do need to use sunscreen, make sure it’s a reef-safe sunscreen. First, avoid spray-on (aerosol) sunscreen, as the spray disperses into the environment much more easily than a cream, and often contains harmful chemicals. Instead, opt for a mineral sunscreen with zinc oxide and titanium dioxide that aren’t nanoparticles (if the packaging doesn’t explicitly say “micro-sized” or “non-nano,” you can be pretty sure it contains harmful nano-sized particles).
To figure out if a sunscreen is truly reef friendly, look at the label. Make sure to avoid these chemicals:
Finally, while sunscreen in the ocean is clearly harming coral reefs, we must also take into consideration the other threats to coral reefs, including overfishing and climate change’s rising temperatures. Changing to a reef-safe sunscreen may make a small dent, but we must curb climate change in order to truly protect coral reefs and other marine life.
Ocean acidification occurs when the pH level of seawater decreases. This is most frequently caused by the ocean absorbing excess CO2 from the atmosphere. Some legislatures have enacted laws that address ocean acidification either directly (as the subject of legislation) or indirectly (through laws that target carbon emissions).
This article will examine laws related to ocean acidification that have been enacted in countries around the world, as well as how they may help address ocean acidification and its consequences.
There are several laws enacted around the world that work to fix the problem of ocean acidification. While not all of these laws were intended to address ocean acidification specifically, many may still work indirectly to reduce acidification.
United States
The Clean Air Act
The main goal of this federal law is to regulate sources of air pollution. It was created by the Environmental Protection Agency (EPA), which sets requirements for all states to provide a strategic plan in order to reduce carbon emissions in order to protect public health and the environment. The law may not be specifically intended to address ocean acidification, but because ocean acidification is caused by an excessive amount of atmospheric carbon, a nationwide reduction in carbon emissions would have a substantial impact on decreasing ocean acidification.
The Clean Water Act
The Clean Water Act is another U.S. federal law that focuses on the regulation and prevention of water pollution, and the improvement of water quality in the nation. Through this act, the EPA enacted requirements for industries that produce wastewater, created several initiatives to combat water pollution, and implemented standards for surface water contaminants. The Clean Water Act also empowers the EPA to combat ocean acidification since it can be regarded as toxic or chemically imbalanced surface water.
Federal Ocean Acidification Research and Monitoring Act
This federal law mandated the establishment of the Interagency Working Group on Ocean Acidification (IWG-OA). The interagency group is embodied by multiple government organizations led by National Oceanic and Atmospheric Administration (NOAA). The primary goal of the IWG-OA is to conduct research that will provide more information and discoveries regarding the effects of ocean acidification. It also covers the identification of conservation and adaptation plans for marine resources and areas of the country affected by ocean acidification.
State of California
AB 32 and SB 32: Statewide Greenhouse Gas Reduction
Assembly Bill No. 32 (signed into law in 2006) required the state to reduce its greenhouse gas (GHG) emissions in order to meet 1990 GHG levels by 2020, while Senate Bill No. 32 (signed into law in 2016) requires the state to cut its GHG emissions to 40% below 1990 levels by 2030. The reduction of emissions will help to lower the amount of atmospheric carbon in the air for the ocean to absorb, thereby reducing ocean acidification.
SB 1363 (2016): Ocean Protection Council: Ocean Acidification and Hypoxia Reduction Program
Senate Bill No. 1363 (signed into law in 2016) developed the California Ocean Protection Trust Fund. This fund is meant to support any research and projects that are initiated to tackle the ocean acidification problem. For example, 2021 research on the restoration of eelgrass in California to mitigate ocean acidification occurred due to the support of this bill.
AB 2139: Ocean Protection Council: Ocean Acidification and Hypoxia Task Force
Assembly Bill No. 2139 (signed into law in 2016) developed a task force that focuses on research about the effects of ocean acidification in order to provide policy recommendations to mitigate ocean acidification.
State of Oregon
SB 1039 (2017): Ocean Acidification and Hypoxia Action Plan
Senate Bill No. 1039 (2017) was created to address the ocean acidification problem in the state. Oregon is impacted by ocean acidification in many ways, including damage to its oyster aquaculture industry. The Oregon Coordinating Council on Ocean Acidification and Hypoxia (OAH Council) was established under this legislation. The main goal of the council is to provide an action plan on how to address ocean acidification and its impact on aquaculture and the environment.
SB 1554 (2020): Funding for ocean acidification emergency in the state
Senate Bill 1554 (2020) was created to fund the Oregon Ocean Science Trust. This trust works to support initiatives, projects, and research that will help to address the ocean acidification emergency in the state.
State of Maine
LD 1679: An Act to Promote Clean Energy Jobs and to Establish the Maine Climate Council
The bill, passed into law in 2019, established the Maine Climate Council, which conducts studies to identify different factors that cause climate change, warming ocean temperature, and ocean acidification. The council is required to develop guidelines for addressing these environmental problems and adapting to their consequences.
United Kingdom
Climate Change Act of 2008
The Climate Change Act of 2008 was enacted to address climate change. Under this law, the government is required to create a Climate Change Risk Assessment (CCRA) every 5 years. The assessment covers the UK’s risks and opportunities from the effects of climate change. The government is also required to establish the National Adaptation Programme (NAP), which creates different projects for the country’s adaptation to climate change. One of these projects is the UK Ocean Acidification Research Programme.
The Climate Change Act of 2008 also requires the reduction of greenhouse gas emissions, with the goal of becoming “Net Zero” by 2050. This large-scale emission-reduction plan would significantly help to decrease ocean acidification.
New Zealand
The Climate Change Response (Zero-Carbon) Amendment Act 2019
The Climate Change Response (Zero-Carbon) Amendment Act of 2019 mandated the establishment of the Climate Change Commission. The commission’s principal goal is to provide scientifically-grounded recommendations on climate change mitigation and adaptation. This law also aims to achieve “Net Zero” greenhouse gas emissions in the country by 2050. It is the duty of the Climate Change Commission to monitor the country’s progress towards this goal and ensure that the country is on track. The law may not be directly aimed at addressing ocean acidification, but as mentioned above, reducing carbon emissions is the main method to reduce ocean acidification.
European Union
European Climate Law
The European Climate Law was enacted to support the objectives of the European Green Deal, which aims to ensure the EU is climate neutral by 2050. It also provides milestones that must be met on the way to achieving climate neutrality in 2050. For example, the European Union is required by this law to reduce 55% of its greenhouse gas emissions by 2030. The European Climate Law will establish methods to monitor progress toward their objective and to guarantee that the target of climate neutrality by 2050 can be met. Although ocean acidification is not the primary focus of the law, it may be addressed by major emission reductions across the European Union.
Unified International Policy to Address Ocean Acidification
There is still no direct united international policy to tackle ocean acidification, despite the fact that many claim that it is as important as the other global problems that need to be addressed. Some argue that the United Nations may use the United Nations Convention on the Law of the Sea (UNCLOS) to design and develop a unified agreement that specifically addresses ocean acidification.
However, the 2015 Paris Agreement may help reduce carbon emissions, and thus reduce ocean acidification.
The Paris Agreement is a legally binding international treaty designed to address global climate change issues. The treaty’s principal objective is to lower global temperatures by 1.5 to 2 degrees Celsius. The treaty required all participating countries to provide their climate action plans by 2020. In their submitted climate action plans, all of the countries agreed on one thing: they pledged to cut their greenhouse gas emissions in order to accomplish the agreement’s objective.
Beginning in 2024, progress will be tracked through an enhanced transparency framework (ETF), where each of the participating countries will have to submit its progress report for validation.
While the agreement’s primary goal is to combat climate change in general, ocean acidification may be addressed through the combined greenhouse gas emissions reduction efforts of 192 participating countries and the European Union.
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.
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
