Dr. Sarah Cooley explains how changes in ocean chemistry are having a ripple effect on sea life and our economy:
Sarah: So, ocean acidification and global warming have one of the same root causes, carbon dioxide in the atmosphere. So when we burn fossil fuels and when we change land uses and release carbon dioxide into the atmosphere, some of it stays in the atmosphere and about 25% of it goes in the ocean. And when the carbon dioxide dissolves in the ocean, it creates an acid, and that acid is fundamentally changing the chemistry of our oceans and creating ocean acidification as we know it.
Colleen: So I’m thinking of those little pH strips that, I would use them when working in a dye studio dyeing fabric and the water, we would have to test it and make sure that the pH was right before we could dump that water. So, is that more or less what’s happening with the ocean? You could stick a strip in there and see what’s going on?
Sarah: Yes. And there’s actually been international observing efforts to survey what the ocean’s chemistry is for decades now. And both those shipboard observations and observations based at time-series stations… Locations, where measurements are made repeatedly every month, are showing that there is a progressive decline in ocean pH. So, ocean pH has dropped about 0.1 pH units since the Industrial Revolution. And that doesn’t sound like a lot, but it actually is quite a significant change because most of the animals and ecosystems that are in the ocean today are really accustomed to conditions that they’ve had for thousands of years well before the Industrial Revolution even began.
Colleen: Is it happening in the ocean equally in all areas or are there sort of hotspots?
Sarah: So the whole ocean on average is taking up carbon dioxide from the atmosphere. There are certain areas of the ocean that are more prone to take up carbon dioxide than others. For example, high latitudes near the Arctic Ocean and near Antarctica, there’s cold water there, and so the carbon dioxide dissolves more easily into that water. And so that’s one of the areas where the change is happening faster than other areas. There are other areas in the ocean where a lot of processes converge. So, the coastal zones are especially complicated. Not only are coastal zones taking up carbon dioxide from the atmosphere, but they’re also experiencing a lot of influences from land. Some of those influences change the carbon dioxide content of coastal water, and some of those influences also change the pH of that water through other chemical processes separate from carbon dioxide to solution. So, coastal zones are an especially complicated area. And so we know that coastal zones are experiencing acidification, but right now, it’s a real challenge scientifically to peel apart which processes are most responsible.
Union of Concerned Scientists