At this point in time, everyone has a general understanding climate change. Most of us know it causes extinctions, dangerous natural disasters, and more. We also all know that it’s getting worse.

Climate change is partly responsible for most of the issues mentioned in previous blogs like deforestation. Although in truth, most environmental issues we face today influence other environmental issues. Another big issue caused mainly by climate change is ocean acidification.

One big cause of climate change is the increased amount of carbon dioxide in the atmosphere due to human activities. The ocean absorbs 30% of all the carbon dioxide in the atmosphere, and since there is more carbon dioxide in the atmosphere, more of it is getting absorbed by the ocean. When carbon dioxide comes into contact with seawater, it forms a weak acid called carbonic acid, which breaks into hydrogen ions and bicarbonate ions. The increased amounts of hydrogen ions are what has caused the ocean’s pH, to drop by 0.1 pH units from 200 years ago. Since the pH scale is logarithmic, this means the ocean has become 30% more acidic than it used to be. At our current rate of emissions, the oceans will become 120% more acidic by 2100, a level of acidity not seen in the oceans for over 20 million years. 

(This image shows what will happen to the shell of a pteropod in the ocean by 2100) 

There are many effects that the increase in acidity has on wildlife in the ocean. Many shell-bearing animals like mussels and clams make their shells from calcium carbonate, but this is becoming increasingly difficult because hydrogen ions have a stronger attraction to carbonate than calcium does. So the increase in hydrogen ions results in more and more of the available carbonate being used up. Most shell-bearing organisms cannot use the bicarbonate that results from the union between hydrogen and carbonate ions, to make their shells. The increased acidity of the ocean also corrodes existing carbonate shells.

The same problem that affects shell-bearing animals, affects coral reefs, due to their carbonate skeleton. However some reefs can use bicarbonate, some can temporarily last without a skeleton (and rebuild when conditions become more favorable), and some can even last in more acidic conditions. But a majority of reefs will be negatively affected since they will struggle to grow their skeletons, which are simultaneously being dissolved. As a result, this will make most reefs weaker and more susceptible to erosion. In fact, by 2080, healthy reefs will be eroding faster than they can rebuild. It should be noted that 25% of all marine life relies on reefs at some point in their lives. Coral reefs, also have to deal with another major issue, bleaching, check out my mini-blog to learn more about this issue.

Click Here to Read Coral Bleaching Miini-Blog



Two major species of zooplankton will also be affected due to their calcium-carbonate shells. This is problematic as these animals are the base of the oceanic food web, since most ocean animals either eat them or eat animals that eat them. Zooplankton are also an important part of the carbon cycleMost oceanic plants and algae will do well, as carbon dioxide is a key part of how they make food.  However coralline algae which builds calcium carbonate skeletons and helps reefs, will not do so well(without this type of algae, other types of algae that damage reefs will grow).  Even non-carbonate shelled animals like fish will be negatively affected. In order to be in balance with the seawater, fish will absorb more carbonic acid changing the pH of their blood. This affects their survival as they have to use more energy (which they could be used for other important tasks) to bring their body chemistry back to normal. 

There are also different neurological effects seen in fish.  For example, a more acidic ocean results in clownfish being less reactive to noise, which results in them not fleeing from noisy predators, they also struggle to navigate back to their home in these conditions. It should be noted that some areas in the ocean are naturally more acidic due to CO2 emitted from volcanic vents. Sciteints have noted that are fewer corals and calcium-carbonate shelled animals near these vents, a model for what oceans may look like in the future.  

Ocean wildlife is not the only one affected by this issue, and so are humans. 4.5 billion people get at least 15% of their animal protein intake from fish, this jumps up to over 50% in some countries and many small islands. Ocean acidification will result in a decrease in fish whether due to the decline of zooplankton or coral reefs. This issue can also lead to harmful algal blooms, some of which release toxic aerosols that are harmful to human health. There’s also the loss of livelihoods as over 300 million people get their income from marine fisheries, not to mention the loss from things like eco-tourism, due to the decline of the reefs. 

If we are to solve ocean acidification, we are going to have to stop climate change because the main cause of both lies in the amount of carbon dioxide that humans emit. There is another way as well by using a form of geoengineering that involves fertilizing the oceans in order to cause phytoplankton blooms which would absorb the carbon dioxide from the atmosphere. Then, when they die, they would sink to the deep sea take the carbon with them. However, this method, like all geoengineering could likely be quite problematic

There are several other issues that affect the oceans, to learn more about them check out the following resources: 

  1. Ocean pollution: Here and here  
  2. Overfishing: Here and here  
  3. The oil industry: Here and here 
  4. Climate change: Here and here  
  5. Dredging: Here and here  


Looking for some ways to help?  


  1. Lower your carbon emissions; You can do this by eating less meat, biking short distances instead of driving, using clean energy
  2. Check out this link for more ways to reduce emissions 
  3. Lower your plastic usage 
  4. There are alot of carbon emissions associated with plastics. If you’re looking for some specific ways to help, check out the “looking for some ways to help ?” section of my previous blog “plastic pollution: it’s in everything, now it’s everywhere”  OR check this out(some of these things may be hard to do, but any little bit helps) 
  5. Educate others; Compared to other environmental issues mentioned in the previous blogs, Ocean acidification is not as well known. The more people that know about it, the greater the chance that some action will be used