Saturday, June 6, 2015

Why do we care about CO2 in the ocean?

Well, we humans are emitting a lot of carbon dioxide, and about 40% of what we’ve emitted has been sucked up from the atmosphere by the ocean. The ocean can hold a lot of carbon dioxide because the carbon can hide in all of those various forms (see post below) although the ocean uptake rate might go down in the future.  The ocean soaking up carbon dioxide is both a good and a bad thing.  It’s a good thing because carbon dioxide in the ocean does not trap the heat our Earth is radiating back out into space, and therefore doesn’t contribute to global warming like carbon dioxide in the atmosphere does.  It’s a bad thing because all of this extra carbon means the ocean is becoming more acidic (arguably less basic) due to all of the extra carbonic acid being formed from carbon dioxide.  

Now, you don’t have to be afraid of your swim trunks dissolving in corrosive seawater anytime soon.  Even the most extreme projections of what might happen still have the ocean more basic than perfectly neutral drinking water, and way less acidic than Coke… but it is still a pretty big concern for the organisms that evolved in the basic ocean and, presumably, like it that way.  There are a couple of critters at or near the base of the ocean food chain that form shells out of a mineral formed from carbonate, which is the most basic of carbon dioxide’s many guises.  Computer model simulations suggest that the availability of carbonate could decrease by 50% by the year 2100 if we continue emitting carbon dioxide as we have.  There are other important creatures that make their shells out of the same mineral, including ones we eat (e.g. clams) and ones that create entire habitats that other species rely on (e.g. corals).  There’s a huge amount of ongoing research into what this would do to these critters and the creatures that rely on them, but I’ll sum it up by saying that I’m worried for the little dudes.  I’m just imagining the reverse situation of some sea creature venting gas into the atmosphere that dissolves our bones, and it’s making me unhappy!
By Brendan Carter
Taking CO2 water samples
CO2 lab