Scientists have predicted that climate change will continue to deplete nutrients in the world’s oceans, which will reduce how much carbon dioxide is absorbed.
Enter the mighty plankton.
Turns out, in relation to the amount of available nutrients, ocean plankton are removing carbon dioxide – a major driver of climate change – at twice the rate than originally thought.
That means a nearly 80-year-old study by Alfred Redfield, used by most scientists today to understand the biochemistry of the oceans, needs an update.
“We’ll have to rewrite some textbooks,” said Adam Martiny, associate professor of Earth System Science and Ecology & Evolutionary Biology at UC Irvine, who led the research team.
WHAT ARE PLANKTON?
Phytoplankton are microscopic organisms that perform the same task as plants and trees, but they do their job in the ocean. They grow with sunlight, carbon dioxide and nutrients (phosphorus and nitrogen).
Zooplankton eat what the phytoplankton produce.
Plankton are highly underrated, Martiny said. “They’re equally important as plants for how the world works,” he said.
The smallest phytoplankton in the ocean, the Prochlorococcus, absorb more carbon dioxide than all of the trees in North America.
The team discovered planktons’ increased capacity to absorb carbon dioxide by collecting and analyzing the world’s ocean water.
REDFIELD OUT, UCI IN
In 1934, Redfield came up with the Redfield Ratio, which says the concentration of carbon dioxide to nitrogen to phosphorus in the ocean is the same ratio seen in ocean plankton.
Redfield’s ratio of carbon to nitrogen to phosphorus was fixed for the world’s oceans at 106:16:1.
“Instead of the fixed ratio, we found variation with latitude,” Martiny said.
“It’s the most important study I’ve ever done in my career.”
UCI researchers concluded that leaner plankton, in waters with fewer nutrients available to them, are more carbon-rich than the fatter plankton with more nutrients available to them.
Low-latitude oceans near the equator have low nutrient (nitrogen and phosphorus) levels, more carbon and leaner plankton.
The ratio of carbon to nitrogen to phosphorus: 195:28:1.
High-latitude oceans near Polar Regions have high nutrient content, low carbon content and fatter plankton. The ratio: 78:13:1.
“Even if the phytoplankton gets less nutrients, they take up more carbon than we thought.”
The research team
Adam Martiny, Chau Pham, Francois Primeau, Jasper Vrugt, J. Keith Moore, Simon Levin and Michael Lomas.
