A recent study published on July 4, 2025, reveals that zooplankton migration plays a significant role in carbon storage in the Southern Ocean, a process that has been largely overlooked in climate models.

Zooplankton, including copepods, krill, and salps, are crucial for carbon storage, migrating deep into the water and trapping significant amounts of carbon each year.

Copepods are identified as the dominant species in this carbon flux, responsible for about 80 percent of the total carbon storage, followed by krill at 14 percent and salps at 6 percent.

These small marine organisms consume phytoplankton in the spring, storing fat before migrating to depths of 500 to 2,000 meters in the Antarctic, where they burn the fat and effectively lock away carbon dioxide.

The Southern Ocean absorbs around 40 percent of human-released CO2 that enters oceans, making the role of these zooplankton critical in combating climate change.

The carbon storage capacity of zooplankton is estimated to be equivalent to the annual emissions of approximately 55 million petrol cars, significantly more than previously recognized by scientists.

The findings indicate that current Earth System Models neglect the impact of zooplankton on carbon dynamics, which may change as warming alters species distributions and food sources.

The study emphasizes the need to update climate models to incorporate this efficient carbon sequestration pathway, highlighting the importance of protecting zooplankton habitats as climate change alters their distribution.

Researchers recommend integrating the findings on zooplankton into climate models to better predict future atmospheric CO2 levels and global warming effects.

However, the future of zooplankton is threatened by climate change, changes in ocean stratification, and commercial krill harvesting, which could diminish their population and the carbon they store.

In 2020, nearly half a million tons of krill were harvested, raising concerns among environmentalists about the impact on marine ecosystems.

This international study involved collaboration among scientists from China, the UK, and Canada, utilizing a century's worth of data on zooplankton.