Ocean Acidification. Referred to by international scientists as an “Evil Twin” to climate change [-Climate Change’s ‘Evil Twin’: Ocean Acidification by Carol Smith].  Just like climate change, many people doubt its existence, even if they know it is scientifically proven. It has been researched by scientists for decades, but only being more widespread to the public in the early 2000’s. 

Puget Sound is a little trickle of seawater that goes around halfway through Washington State, which is part of the USA. It is commonly known for its seafood, starbucks, giant tech companies, often gloomy weather, and a large city by the name of Seattle. One thing that is not known by much of the general public is that it is a place that is often researched on for this Ocean Acidification, which is causing it a lot of problems.

Above: a picture of puget sound. [See picture citation 1]


First of all; what is ocean acidification, and how does it happen?

Ocean Acidification is caused mostly by the ocean absorbing around 30% of atmospheric CO2 (much of these are from carbon emissions). The water and carbon dioxide combine with carbonate ions that are taken from organisms such as shelled creatures and coral. A chemical reaction occurs, changing the H20, CO2, excess hydrogen and carbonate ion into 2 bicarbonate ions, which causes acidity to the water. 

A diagram of ocean acidification [See picture citation 2]


Some other factors that may cause the ocean to have acidity include when waters from the higher areas of the ocean and deeper areas of the ocean mix less, causing the chemistry to be less evenly spread, for example; less fresh water at the bottom, and less salt water at the top. 

Due to coastal upwelling, deeper water tends to be more acidic because of organisms and other organic substances decomposing closer to the ocean floor. Although this occurs naturally, we do have some control over the ocean’s acidity. According to the Acidic Waters of Puget Sound article by Hannah Hickey, published in the School of Oceanography website, around 13-22% of the ocean’s acidity comes from CO2 emissions; which is a lot more than it seems! We can also dispose of our waste much more responsibly to prevent unneeded organic matter from decomposing in the ocean, and more! [See the And how can we solve them? section for more]


“And how is this a problem?” You may ask.

First of all, having an acidic ocean would never be a good sign. Bodies of water fill up a massive portion of our earth, and hold the overwhelming majority of life on our world, and acidity is nearly never a good sign, and most obviously would encounter at least some kind of threats. 

This is also not a good sign because the carbonate ions that are needed to create this acidity are part of the bodily structure of many marine organisms; such as corals, clams, crabs, starfish, and other calcifying creatures. These organisms require the carbonate ions so that they can grow and develop to a healthy potential; if they do not have these, they will be weaker. It is essential to their wellbeing to have these carbonate ions as part of their shell/skeletal structure, and if they do not have it, they will slowly drop in numbers and become endangered. Although not all marine organisms need these carbonate ions directly, much of the food that they need, or the food that eats them, require these carbonate ions. This damages the entire oceanic ecosystem, making the numbers of particular animals surge too high or too low; in order for life to flourish, there must be a certain level of balance between the living things. 

An example of some calcifying organisms. [See picture citation 3]


Sometimes, it directly affects other creatures as well. According to the NOAA’s page called What is Ocean Acidification?, some types of fish find it harder to detect threats to their survival, such as predators or other potential disasters that could permanently terminate their existence. This is another way that Ocean Acidification can mess up the food web and the ecosystem; the overwhelmingly low amounts of fish could result in high amounts of whatever it is that they tend to consume, and scarcer food for whatever it is that usually eats them, causing a chain affect on the ecosystem. 

The lower amounts of these particular types of fish, calcifying creatures, and pretty much every other organism that is eaten by us humans in the ocean also negatively affect the seafood industry, which is a huge industry that many people live off of, and many need to continue having a stable food supply. 

Ocean Acidification is also a recipe for unhealthily low levels of pH in the water. The lower levels of pH translate to acidity because lower pH often results in higher amounts of hydrogen ions, increasing the acidity of the ocean. As said in First of all; what is ocean acidification? And how does it happen?, excess hydrogen is part of the chemical reaction into 2 bicarbonate ions. The CO2 results in lower pH which results in more hydrogen ions, which overall causes the acidity. These lower levels of pH are caused by higher levels of CO2 in the water. 

An example of how pH needs to be regulated. [See picture citation 4]


Hypoxia is another prominent problem caused by acidification. One of the definitions of Hypoxia is an “oxygen deficiency in a biotic environment” [-oxford languages, off google search]. Due to the higher amounts of CO2 being absorbed in the ocean, there are lower amounts of oxygen. This makes breathing harder for many marine mammals, especially the ones that reside in the deep sea, causing them to use more oxygen while they exhale even more carbon dioxide, which results in very low levels of oxygen, or in other words, hypoxia. Many marine animals require oxygen for their respiratory systems, and would suffer and die without it. As mentioned before, this would wreak havoc on the ecosystem, causing too many sea animals to become endangered or extinct, and allow their plant counterparts to grow in tremendously dangerous abundance. 


What are the particular problems for puget sound, then?

As said above, in the “And how is this a problem?” You may ask section, some of the major problems surrounding ocean acidification include hypoxia, lower levels in pH, the food web, ecosystem, seafood industry, marine organisms wellbeing [specifically calcifying creatures], the acidity itself, and more. 

Puget sound is one of the many places where there has been a lot of research on Ocean Acidification. It has been a place for marine research by researchers from NOAA, UW, the WA department of ecology, and more. 

The pacific-specific coastal winds result in the specialized coastal upwelling [see above in And how is this a problem? You may ask]. According to James Murray, who is a professor in the UW school of oceanography; most water from Puget Sound is from where we call the “California Undercurrent”, which is around the coast of Mexico. This brings water that is high in many nutrients; especially CO2. The wind goes north, bringing the water to the Puget Sound area [evidence from Acidic Waters of Puget Sound article by Hannah Hickey]. These nutrients help make Puget Sound even more acidic than it would be initially.

Friday Harbor’s research lab, which is right next to the Salish Sea (just north of Puget Sound) [See picture citation 5]


As stated earlier, the seafood industry is a huge industry that many people live off of, with a source of money and/or food. This industry is even bigger in coastal areas, especially the puget sound area and the Washington State coast. Due to the food web and ecosystem being ruined by the Acidification, there is less supply of the marine creatures that we humans consume, harming the industry and the amount of food that we have. 


And how can we solve them?

As mentioned earlier in the article: “ Although this occurs naturally, we do have some control over the ocean’s acidity. According to the Acidic Waters of Puget Sound article by Hannah Hickey, published in the School of Oceanography website, around 13-22% of the ocean’s acidity comes from CO2 emissions; which is a lot more than it seems! We can also dispose of our waste much more responsibly to prevent unneeded organic matter from decomposing in the ocean, and more!” 


A few little actions that would help Puget Sound (in specifics) a lot include educating yourself even more on Ocean Acidification, especially in the area (check out some of the citations and other websites where you can learn more!). You can also volunteer to help the local environment (which is easiest if you live in the area), and maybe get into oceanography, marine biology, or another field where you can help decrease ocean acidification. 

Some other things that we can do to help Puget Sound (and the world) is reduce our waste (and sort trash correctly), rideshare, eat cautiously [understand how it connects with the world], think about how you might affect the environment, voice your opinions/needs, reduce CO2 emissions (your carbon footprint), try not to pollute as best you can, and make more sustainable choices! 




Climate Change’s ‘Evil Twin’: Ocean Acidification by Carol Smith, 

NOAA (US):,sea%20shells%20and%20coral%20skeletons.

UW:  (Acidic Waters of Puget Sound article by Hannah Hickey)

Hypoxia: “oxygen deficiency in a biotic environment.” [Definitions from Oxford Languages] 


  1. G. Brewer, E. T. Peltzer. Limits to marine life. Science. 2009. Vol 324, Issue 5925. April 16, 2009

Picture citations:



3] “Examples of marine calcifiers from Kleypas et al. 2006: (a) coralline algae (photo by Nancy Sefton; courtesy NOAA/CORIS); (b) Halimeda (photo by James Watt; courtesy NOAA/NMFS); (c) benthic foraminifera (courtesy P. Hallock); (d) reef-building coral (Dendrogyra cylindrus; Cmdr William Harrigan, NOAA Corps; courtesy Florida Keys National Marine Sanctuary); (e) deep-water coral (Lophelia pertusa; from 413 m depth off North Carolina. Large red crab is Eumunida picta; urchin below it is Echinus tylodes; courtesy S.W. Ross, K. Sulak, and M. Nizinski); (f ) bryozoan (courtesy NOAA/Ocean Explorer); (g) mollusk (oyster reef; courtesy South Carolina Department of Natural Resources); (h) echinoderm (brittle star; Larry Zetwoch; Florida Keys National Marine Sanctuary); (i) crustacean (lobster; Dr. James P. McVey, NOAA Sea Grant Program)”




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