How fish play a critical role in the oceanic carbon cycle

It wasn't a glitzy or dung-free task by any stretch of the imagination. Wearing gloves, University of Miami marine biologist Martin Grosell and his two colleagues sifted through hundreds of gallons of seawater filled with fish poop, extracting from the feces what would amount to just a few grams of fish carbonate crystals. While the tiny pellets they collected during a weeklong field trip at Panama's Achotines Laboratory may look worthless, their value in helping to offset one of climate change's biggest impacts-ocean acidification-could be priceless. And that is why Grosell and his fellow colleagues at the Rosenstiel School of Marine, Atmospheric, and Earth Science are leading a $1.45 million National Science Foundation study aimed at determining just how big of a role fish play in the global carbon cycle. "The fish component is not incorporated to the extent it should be into current models that assess the carbon cycle in our oceans and how it influences climate,” said Grosell, professor and chair of the Rosenstiel School's Department of Marine Biology and Ecology. "So, we're missing a very big piece of the carbon cycle puzzle in terms of what we understand and what we can predict. And that missing piece is likely going to become more important as our oceans warm and become more acidic.