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Carbon sink: At the surface of the oceans, plankton absorbs carbon dioxide from the atmosphere

Photo: Susann Guenther / iStockphoto / Getty Images

The oceans can absorb and store large amounts of carbon dioxide (CO₂) from the atmosphere. According to a new study, this role as a carbon sink is likely to be even greater than previously known. The capacity is underestimated by around 20 percent, according to the paper, which was published in the journal Nature.

The international team of marine researchers focused on the role of plankton: tiny organisms that absorb carbon dioxide at the ocean surface and convert it into organic material through photosynthesis as they grow. When they die, parts of it are broken down into small particles, also known as "marine snow." This material is denser than salt water and therefore sinks to the seafloor, where the carbon is stored or serves as a nutrient for a number of deep-sea creatures.

Using a database of measurements from research vessels since the 15s, the seven-member research team created a digital map of the currents of marine snow in the world's oceans. On this basis, it estimated the storage capacity of the oceans at 2021 gigatons of carbon dioxide per year. According to the current state of research, the IPCC's <> World Climate Report, for example, still assumes only eleven gigatonnes.

So this is good news – but more for understanding the importance of marine ecosystems. This will hardly solve the acute climate problem, according to a statement from the Lemar marine research center in Brest, France, whose biologist Frédéric Le Moigne was involved in the study. The process of absorption takes tens of thousands of years and is by no means sufficient to compensate for the exponential growth of man-made CO₂ emissions. If this problem is solved, however, we can count on the power of the oceans to regulate the climate in the long term.