The Silent Crisis: Understanding New Threat of Ocean Acidification

• December 17, 2024

Ocean acidification, often referred to as the “evil twin” of global warming, is a growing environmental crisis that poses a significant threat to marine ecosystems and, by extension, to human food security and livelihoods. This phenomenon, caused by the absorption of excess carbon dioxide (CO2) from the atmosphere, is rapidly altering the chemistry of our oceans with far-reaching consequences.

The Science Behind Ocean Acidification

Ocean acidification occurs when the ocean absorbs CO2 from the atmosphere, leading to a decrease in pH levels. Since the Industrial Revolution, the ocean has absorbed approximately 25% of human-caused CO2 emissions, resulting in a 30% increase in acidity

This change is happening at an unprecedented rate, faster than any known change in ocean chemistry in the last 50 million years

The process can be summarized as follows:

1. CO2 dissolves in seawater
2. This dissolution leads to the formation of carbonic acid
3. Carbonic acid releases hydrogen ions, increasing the acidity of the water
4. The increased hydrogen ions bond with carbonate ions, reducing their availability

Impact on Marine Life

The effects of ocean acidification on marine organisms are diverse and potentially devastating:

Calcifying Organisms

Creatures that build shells or skeletons using calcium carbonate, such as corals, mollusks, and some plankton, are particularly vulnerable. The reduced availability of carbonate ions makes it difficult for these organisms to form and maintain their structures

In severe cases, existing shells and skeletons may begin to dissolve.

Fish and Other Marine Animals

Ocean acidification can affect the physiology and behavior of various marine species. For instance:

• Pacific salmon and clownfish have shown impaired ability to differentiate between prey and predators or locate suitable habitats
• Fish larvae may lose their ability to smell and avoid predators
• The overall health of many species can be compromised as they expend more energy maintaining their internal chemistry in more acidic waters

Coral Reefs

Coral reefs are especially at risk. The lower pH results in coral skeletons losing structural integrity, potentially leading to the collapse of entire reef systems

This has profound implications for the numerous species that depend on coral reefs for habitat and the human communities that rely on them for coastal protection, tourism, and other economic benefits.

Ecosystem-Wide Effects

The impacts of ocean acidification ripple through the entire marine food web. As the base of the food chain is affected, such as plankton and small shellfish, the effects cascade upwards to larger predators and ultimately to human fisheries

This disruption can lead to significant changes in marine ecosystems and potentially alter the ocean’s ability to provide food and other resources for humans.

Global and Regional Variations

While ocean acidification is a global phenomenon, its effects are not uniform across all regions:

• Polar oceans, including the Southern Ocean, are particularly vulnerable due to their naturally low levels of calcium carbonate and higher CO2 absorption rates in cold water
• Tropical areas may see less severe pH changes but face compounded threats from ocean warming and deoxygenation
• Coastal areas can experience more rapid acidification due to additional factors such as nutrient runoff and pollution

Economic and Food Security Implications

The potential economic impact of ocean acidification is substantial, particularly for communities dependent on marine resources:

• Global fisheries catch potential could decline by as much as 12% by 2100, with 3.4% attributed to ocean acidification alone
• In Southeast Asia, where more than 60% of the population lives within 60 kilometers of the coast, ocean acidification threatens both food security and livelihoods
• The loss of coral reefs could result in significant economic losses, with one study estimating that reefs in Southeast Asia provide approximately $10.6 billion in economic benefits

PHAROS Project: Mitigating Ocean Acidification Through Ecosystem Restoration

The PHAROS project, while primarily focused on biodiversity restoration, plays a crucial role in indirectly combating ocean acidification through its innovative nature-based solutions. By revitalizing marine ecosystems, PHAROS contributes significantly to balancing ocean chemistry, which is essential for mitigating acidification and protecting marine life.

Integrated Multi-Trophic Aquaculture (IMTA) and Ecosystem Balance

PHAROS’s implementation of IMTA systems in Gran Canaria and Ireland demonstrates how sustainable aquaculture practices can help mitigate ocean acidification:

• CO2 Sequestration: The cultivation of macroalgae in these systems actively absorbs CO2 from the water, helping to reduce local acidity levels.
• Nutrient Management: By absorbing excess nutrients from fish farming, macroalgae prevent eutrophication, which can exacerbate acidification in coastal areas.
• Habitat Creation: The artificial reefs and macroalgae systems provide habitats for diverse marine life, enhancing biodiversity and ecosystem resilience against acidification.

Biodiversity Enhancement and Ocean Chemistry

The project’s focus on biodiversity restoration indirectly supports the ocean’s natural buffering capacity against acidification:

• Ecosystem Resilience: By restoring and protecting diverse marine ecosystems, PHAROS enhances their ability to withstand and adapt to changing ocean chemistry.
• Natural pH Regulation: Healthy, biodiverse ecosystems are better equipped to maintain local pH levels through biological processes and interactions.

Technological Integration for Adaptive Management

PHAROS’s use of advanced monitoring technologies, such as the Digital Twin Ocean (DTO) system, enables real-time tracking of ecosystem health and ocean chemistry:

• Early Detection: Continuous monitoring allows for early detection of acidification trends, enabling prompt intervention.
• Data-Driven Solutions: The DTO system facilitates adaptive management strategies to address acidification challenges as they arise.

Community Engagement and Long-term Impact

By involving local communities through open-schooling projects, PHAROS fosters a collective commitment to ocean conservation:

• Awareness and Education: Engaging stakeholders in ecosystem restoration efforts raises awareness about ocean acidification and its impacts.
• Sustainable Practices: Community involvement promotes the adoption of sustainable practices that can help mitigate local acidification effects.

The PHAROS project’s holistic approach to marine ecosystem restoration and sustainable ocean use demonstrates the potential for nature-based solutions to address complex environmental challenges like ocean acidification. By enhancing biodiversity, promoting sustainable aquaculture, and engaging communities, PHAROS is contributing to a more resilient ocean ecosystem capable of withstanding the threats posed by acidification. As these initiatives continue to evolve and expand, they offer valuable insights into how integrated, ecosystem-based approaches can play a crucial role in maintaining ocean health and mitigating the impacts of climate change.

The Path Forward

Addressing ocean acidification requires a multi-faceted approach:

1. Reduce CO2 Emissions: The most crucial step is to dramatically reduce greenhouse gas emissions to slow the rate of acidification

2. Enhance Monitoring: Improve data collection and monitoring of ocean chemistry, especially in vulnerable regions like Southeast Asia

3. Protect and Restore Ecosystems: Invest in the restoration of coastal blue carbon ecosystems such as mangroves and seagrass meadows, which can help mitigate acidification locally

4. Develop Sustainable Aquaculture: Expand investment in resilient and sustainable aquaculture to support food security

5. Support Research: Continue studying the impacts of acidification on various species and ecosystems to inform targeted conservation efforts.

Ocean acidification is a silent crisis that demands immediate attention and action. As we work to reduce carbon emissions and mitigate climate change, we must also focus on understanding and addressing the specific threats posed by acidifying oceans. The health of our marine ecosystems, global food security, and the livelihoods of millions depend on our ability to confront this challenge head-on.

References

1. ASOC. (n.d.). Ocean Acidification. Retrieved from https://www.asoc.org/learn/ocean-acidification/

2. Orr, J.C., et al. (2021). Ocean Acidification and Its Impacts on Marine Ecosystems. Frontiers in Marine Science, 8, 596644. Retrieved from https://www.frontiersin.org/articles/10.3389/fmars.2021.596644/full

3. U.S. Environmental Protection Agency (EPA). (n.d.). Effects of Ocean and Coastal Acidification on Marine Life. Retrieved from https://www.epa.gov/ocean-acidification/effects-ocean-and-coastal-acidification-marine-life

4. Fulcrum. (2022). Eating Away Our Food: Ocean Acidification Impacting Fisheries in Southeast Asia. Retrieved from https://fulcrum.sg/eating-away-our-food-ocean-acidification-impacting-fisheries-in-southeast-asia/

5. NOAA Fisheries. (n.d.). Understanding Ocean Acidification. Retrieved from https://www.fisheries.noaa.gov/insight/understanding-ocean-acidification

6. European Environment Agency (EEA). (n.d.). Ocean Acidification Indicator. Retrieved from https://www.eea.europa.eu/en/analysis/indicators/ocean-acidification

7. Smithsonian Ocean. (n.d.). Ocean Acidification and Marine Life. Retrieved from https://ocean.si.edu/ocean-life/invertebrates/ocean-acidification

8. Fulcrum. (2022). Eating Away Our Food: Ocean Acidification Impacting Fisheries in Southeast Asia. (Duplicate Reference). Retrieved from https://fulcrum.sg/eating-away-our-food-ocean-acidification-impacting-fisheries-in-southeast-asia