A recent study revealed that the **zooplankton of the Southern Ocean**, especially **copepods**, undergoes a seasonal vertical migration that **transports carbon to the deep sea**, significantly contributing to **mitigating global warming**.
This little-known but highly effective natural process is equivalent to **capturing the annual emissions of 55 million diesel vehicles**, according to calculations based on data from the U.S. Environmental Protection Agency.
A biological pump regulating atmospheric CO₂
Every spring, millions of zooplankton feed intensively on **surface phytoplankton**, transforming the carbon captured by photosynthesis into **body fat**. They then descend between **500 meters and 2 kilometers** deep, where they **slowly burn that fat** during the winter.
This behavior, known as the **seasonal vertical migration pump**, allows the **carbon dioxide** released to remain **trapped in the deep ocean** for long periods, preventing it from quickly returning to the atmosphere.
Copepods, krill, and salps: the protagonists of marine carbon sequestration
Although often overshadowed by emblematic species like **whales or penguins**, Antarctic zooplankton plays an essential role in **regulating the planet’s climate**.
**Copepods**, tiny relatives of crustaceans, lead this process, followed by **krill** and **salps**.
Microscopic studies reveal fat deposits in their bodies, which serve as **energy reserves** during hibernation in the depths.
The Southern Ocean: epicenter of global cooling
The oceans have absorbed nearly **90% of the excess heat** produced by the burning of fossil fuels. Of this total, the **Antarctic Ocean** accounts for approximately **40%**, and much of this capacity is due to the **zooplankton migratory cycle**.
This finding necessitates a **reassessment of climate models** and recognizing the value of these organisms in the **global carbon dynamics**.
Science under extreme conditions: nets, microscopes, and red light
During a recent expedition aboard the polar vessel **Sir David Attenborough**, scientists from the **British Antarctic Survey** and the **University of Exeter** captured zooplankton near the **South Orkney Islands** and **South Georgia**.
To avoid altering their behavior, they worked in **dark environments with red light** and temperatures of **3 to 4°C**, observing the microscopic details of their physiology for hours.
Increasing threats: industrial fishing and climate change
**Warming waters**, **ocean layer disruption**, and **commercial krill fishing** pose **serious risks** to the stability of Antarctic zooplankton. In 2020, nearly **500,000 tons of krill** were caught, a legal practice but questioned by environmental organizations and documentaries like **David Attenborough’s** *Oceans*.
According to the **Plymouth Marine Laboratory**, if this **biological pump** were to disappear, atmospheric **CO₂ levels could double**, underscoring the **urgency of protecting these invisible ecosystems**.
A call to incorporate zooplankton into climate models
Recognizing their role is key to projecting more accurate future scenarios.
Researchers insist that **new data on migration and carbon sequestration** must be integrated into **climate prediction models** to more accurately reflect the role of oceans in **absorbing greenhouse gases**.
The study was published in the scientific journal *Limnology and Oceanography*.
