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WHOI scientists find ocean’s carbon pump twice as effective.

WHOI scientists shared some positive news on the ocean’s ability to manage rising carbon levels. New research published in Proceedings of the National Academy of Sciences found that the top layer of the ocean may be providing twice the carbon sink than previously thought. The reason is a highly productive area near the ocean’s surface that may be doing more work than accounted for.

Euphotic Zone Is Home to Plankton

The ocean is dark and deep, but sunlight on the surface plays a key role in ocean health. This euphotic zone is home to sun-loving plankton. Plankton are like a vast mixed crop, livestock network of plants and animals that are critical to a healthy marine ecosystem. Plankton serve as the base of the marine food web and are critical to every commercially harvested fish.

They also do an important job moving carbon. Phytoplankton, the plant plankton, use sunlight to convert carbon in the water into food. And all plankton distribute carbon as food or to the seafloor as waste. This is known as the carbon pump, and it transfers about 10 gigatons of carbon from the atmosphere to the deep ocean annually.

Ez Has Deeper, More Productive Areas

Source: PNAS

Previously scientists had measured the depth of the euphotic zone, or Ez, to a fixed point. But this study looks at the Ez in a new way. WHOI scientists showed that the depth of the sunlit area varies across the ocean. Some zones are more shallow and other areas have greater depth and therefore will be more productive in moving carbon.

“The fixed-depth approach underestimates biological carbon pump efficiencies when the Ez is shallow and overestimates it when the Ez is deeper,” the researchers said. Their findings show the carbon pump may be twice as effective.