In 2006, when I first heard about ocean acidification, I started running expeditions near underwater volcanoes in the Mediterranean where CO2 bubbles up through the sea floor, acidifying large areas for centuries. We have found similar ecosystem shifts at all the seeps, so I am now convinced that ocean acidification will bring change. In a recent article I attempt to put this topic into context, focusing on two major causes of change – the corrosive effects of CO2, and the way the extra carbon is used as a resource.
Here’s what we’ve noticed about the sea life around those natural CO2 seeps in the Mediterranean: algae seems to thrive, whereas animals with calcium carbonate shells—like plankton—dissolve away. We see a lot of brown seaweeds on the seafloor, and they often overwhelm slower-growing competitors like corals. Although life is abundant at CO2 seeps, there is far less diversity than we see elsewhere.
This post is a collaboration between Sarah Cooley, Ph.D. (Ocean Conservancy), Ryan Kelly, Ph.D., J.D. (U. Washington) and C. Mark Eakin, Ph.D. (NOAA)
Readers of this blog know that ocean acidification is here, today. They also know that states on both coastsand the federal government are working to halt its progress and manage its impacts. But the ocean is heedless of borders. A healthy ocean future will require global action. That is why we have our eyes on December’s Paris climate conference (COP21). Decisions made there will determine whether our children will inherit a changed-but-recognizable ocean that still provides humanity with goods and services, or a damaged ocean lacking many resources we want. There is still time for us to reduce emissions and slow the warming and acidification of our ocean, but we have to act now. That is one of the conclusions we reach in a paper out today in Science.
Donning our snorkel gear, my son and I entered the tranquil bay. We’d been looking forward to spring break in Baja Mexico and had read about this spot in the guide book. But we were soon disappointed; there were few fish to see and most of the coral was damaged or dead. The unsuspecting tourist might not notice but as a trained marine biologist I know what a healthy reef looks like. This wasn’t it.
Coral reefs are under assault. Overfishing and coastal development are partly to blame, but ocean acidification is an emerging threat to corals and a host of other species that rely on calcium carbonate for their shells. As CO2 increases in the atmosphere, it dissolves in the ocean and it is changing the very chemistry of the sea.