Hello and welcome to Environmental Minute! This is a segment brought to you by WDIY, in part by the Estate of Don Miles, and I am your host, Maddie Yang, a rising senior in high school at Moravian Academy, in Bethlehem, Pennsylvania. I am super passionate about all things climate change, sustainability, and empowering and educating others to take action against the climate crisis. My goal for this segment is to provide listeners with a glimpse to a whole variety of topics in the vast realm of sustainability from biodiversity to ecotourism, and plant-based diets to sustainable swamps.
Our world’s oceans absorb roughly 30% of carbon dioxide released into the atmosphere. About 90% of these emissions come from the burning of fossil fuels for energy, and the remaining 10% can be attributed to changes in land-use such as deforestation. Aside from causing global warming, extreme weather events, changes in biodiversity, and crop vulnerability, CO2 emissions are also responsible for ocean acidification.
When carbon dioxide is taken in by our oceans, a series of chemical reactions are triggered. The water and carbon dioxide combine to form carbonic acid (H2CO3 if we want to get technical), which is a weak acid. This carbonic acid dissociates into H+ hydrogen ions and HCO3- bicarbonate ions. Overall, this increases the concentration of hydrogen ions, making our oceans more acidic.
Prior to the Industrial Revolution, the ocean’s pH sat around 8.2. However, today its pH is about 8.1.
But how can that be significant you may ask? A literal tenth of a difference cannot do any harm. Well unfortunately, you would be mistaken because the pH scale is logarithmic. So that means every one unit decrease really is a tenfold increase in acidity. Hence our oceans are 25-30% more acidic than they previously were about 200 years ago.
So what does increase in acidity actually mean?
Well for one, our oysters and coral are heavily impacted. Both of these organisms make hard shells through carbonate and calcium, but with more and more of the available carbonate ions bonding with the excess hydrogen, there is less and less carbonate ions available for these animals. And in extreme cases, if the pH gets too low, their shells could start dissolving.
And for non-calcifying organisms such as the clownfish, ocean acidification also poses a threat. Clownfish’s ability to detect predators in waters with lower pHs are shown to decrease, hindering their ability to find suitable habitats. This puts entire food webs at risk.
However, for some organisms, increased ocean acidity is actually a plus. Organisms such as algae and seagrasses benefit from the increased CO2 produced as a result of ocean acidification due to the fact that they require CO2 for photosynthesis.
In terms of the field of ocean acidification, many strides are being made. For instance, the National Oceanic and Atmospheric Administration (or the NOAA) as well as the Global Ocean Acidification Observing Network are responsible for tracking carbon absorption and using technology to predict changes in our ocean’s chemistry.
Furthermore, campaigns led by Oceana, the world’s largest international advocacy organization dedicated to ocean conservation, employ seagrasses, tidal wetlands, and kelp forests to absorb more carbon. And following the Paris Accords, the International Alliance to Combat Ocean Acidification was created to create plans in order to protect our key planetary boundary - the oceans.
Thank you so much for tuning into this episode of Environmental Minute, and I hope this conversation has inspired you to think more deeply about ocean acidification. Until next time, I’m Maddie Yang, and this has been Environmental Minute.
