How Ocean Acidification Impacts Marine Ecosystems

A lot of us have probably heard it at this point: The oceans are dying. Ocean Acidification is killing our reefs. But what does it mean?

It means that for something this well evolved and this beautiful, it makes sense the biggest threat would be invisible and hard to understand. The world's oceans are facing a growing threat that is altering their chemistry and impacting the balance of marine life. Ocean acidification is a process where seawater becomes more acidic due to increased carbon dioxide (CO2) absorption from the atmosphere. Think: the ocean water turning a little more like vinegar.

This change in ocean chemistry has dark consequences for marine ecosystems, affecting everything from tiny plankton to large coral reefs.

Christine Ren posing underwater for a concept shoots explaining Ocean Acidification

The Effects of Ocean Acidification on Marine Life

Ocean acidification happens when CO2 dissolves in seawater, forming carbonic acid. This lowers the pH of the water, making it more acidic. The shift in pH affects marine organisms, especially those hard shells and skeletons, such as corals, mollusks, and some plankton species.

Key impacts include:

• Weakened Shells and Skeletons: Acidic waters reduce the availability of carbonate ions, essential for shell formation. This makes shells thinner and more fragile, increasing vulnerability to predators and environmental stress.

• Coral Reef Degradation: Corals struggle to maintain their calcium carbonate structures, leading to slower growth and increased erosion. This threatens the biodiversity that coral reefs support.

• Disrupted Food Chains: Many marine species depend on calcifying organisms for food. When these populations decline, it affects the entire food web, including fish we rely on for foo.

  
  

These changes can lead to reduced biodiversity and altered ecosystem functions, impacting fisheries and coastal communities that rely on healthy oceans.

Coral Reef progression from healthy, to struggling, to mostly dead

How Ocean Acidification Affects Different Marine Ecosystems

Different marine ecosystems respond differently to ocean acidification, depending on their species composition and environmental conditions.

Coral Reefs

Coral reefs are some of the most vulnerable ecosystems. If you are here you have probably heard of coral bleaching, there coral heads will turn white as their last resort before dying. In this case the role of acidification slows coral growth and weakens their skeletons, making reefs more susceptible to storms and erosion. This loss of habitat affects many species that depend on reefs for shelter and food.

Shellfish Beds

Shellfish such as oysters, clams, and mussels face challenges in shell formation. Acidic waters can cause shell dissolution and reduce larval survival rates, threatening shellfish populations and the industries that harvest them.

Open Ocean and Plankton

Plankton, including coccolithophores and pteropods, play a critical role in carbon cycling and as a food source for many marine animals. Acidification can impair their ability to form shells, disrupting oceanic food webs and carbon sequestration processes.

Seagrass Meadows and Mangroves

Interestingly, some ecosystems like seagrass meadows and mangroves may benefit from increased CO2, as it can enhance photosynthesis. However, these benefits may not offset the broader negative impacts on surrounding marine life.

Kelp forest and electric ray shedding its mucus layer due to poor water conditions

What are Three Interesting Facts or Impacts of Ocean Acidification?

Ocean Acidification is Happening Faster

The current rate of acidification is unprecedented in geological history, largely due to human activities increasing atmospheric CO2 levels.

Pteropods, Also Known as Sea Butterflies, Are Indicator Species

These tiny marine snails have delicate shells that dissolve quickly in acidic conditions. Their decline signals broader ecosystem stress.

Economic Impact on Fisheries and Aquaculture

Ocean acidification threatens global seafood supplies, potentially costing billions in lost revenue and affecting food security for millions of people.

These facts highlight the urgency of addressing ocean acidification to preserve marine biodiversity and human lives.

Bleached and dead coral head in Hawaii

Practical Steps to Help and Adapt to Ocean Acidification

While ocean acidification is a global issue, there are actions that individuals, communities, and governments can take to mitigate its effects and adapt to changes.

Reduce Carbon Emissions

The number one cause of ocean acidification is CO2 emissions. Reducing fossil fuel use, increasing energy efficiency, and investing in renewable energy sources are critical steps. I know going full green is almost impossible nowadays but anything helps!

Protect and Restore Marine Habitats

Healthy ecosystems like mangroves, seagrasses, and salt marshes can absorb CO2 and help buffer acidification effects. Conservation and restoration efforts support resilience.

Support Sustainable Fisheries and Aquaculture

Cutting fish out of your diet completely is not possible or reasonable for everyone but purchasing from sustainable practices helps both the ocean and you. Shopping local and making sure your fish is caught by local fishermen reduces stress on marine ecosystems already impacted by acidification and helps your community instead of some mega oversea industry.

Promote Research and Monitoring

I know. Science somehow has gotten less and less popular these days, but ongoing scientific research is essential to understand acidification trends and develop effective responses. Supporting monitoring programs, coral restoration efforts, and coral gardens helps track changes and inform policy.

Raise Awareness and Advocate for Policy Change

Educating the public your community and policymakers about ocean acidification is where we shine! As an underwater photographer my way is art. I use my photography to show existing beauty, the raw reality, or to explain a complicated issue like Ocean Acidification. Your way might be environmental law, or teaching your kids to minimize the use of single use items. We can all make a difference! Big or small it always matters.

Looking Ahead: The Future of Our Oceans

The effects of ocean acidification are complex and far-reaching, but understanding them is the first step toward meaningful action. By addressing the root causes and supporting marine ecosystem resilience, we can help safeguard the oceans for future generations.

For more information on how ocean acidification impacts marine life and what you can do to help, visit NOAA.

Together, we can work toward healthier oceans and a more sustainable planet.