The news: We’ve known for decades that plants suck up a large portion of the harmful pollutants our cars and factories emit. Fish, as it turns out, play a critical role too. A new study estimates that fish and other aquatic life absorb 1.5 billion metric tons of carbon dioxide from the atmosphere each year by eating phytoplankton, the ocean creatures that suck up carbon emissions, and other fish.
To put that in perspective, all of the world’s carbon dioxide emissions--from fossil fuels, cement and land use--add up to about 32 billion metric tons. Which means fish are sucking up close to 5% of all of the carbon dioxide humans release.
In case that doesn’t do it for you, the researchers put a dollar figure on the fish’s fight against global warming. Thanks to their contribution, humans save between $74 and $222 billion in climate damage. Per year.
The research was commissioned by the Global Ocean Commission and co-authored by the University of British Columbia’s Rashid Sumalia and the University of Oxford’s Alex Rogers.
The details: Most of the work is being done by bottom-feeders, such as benthic fish and flatfish, who swim up to capture prey and deliver it to their low-down lairs. The fish food chain is commanded by phytoplankton, tiny plant-like organisms that absorb huge amounts of carbon dioxide. Here’s the problem: Even when those tiny creatures are eaten by other fish that live close to the water’s surface, the carbon they’ve captured stays close to the surface and is often simply released back into the atmosphere. Thanks to deep-sea fish, however, all that carbon gets pulled down the the depths of the ocean, where it stays for good.
Image Credits: Flickr/ CDN
Why it matters: The ocean works as a massive carbon storage sink, thanks largely to the creatures that live there. Yet overfishing and international mining activities threaten to reduce the diversity of this ecosystem. We need to think carefully about what we are removing from the sea, and how.