European institutions launch campaign for International Coccolithophore Day
Five European research institutions have announced an initiative to establish October 10 as International Coccolithophore Day, highlighting the crucial role of these microscopic plankton in regulating Earth's climate. Coccolithophores, tiny algae smaller than dust grains, capture carbon dioxide, produce oxygen, and form geological records of climate history. The campaign aims to raise awareness of their impact on ocean ecosystems amid climate change threats.
Coccolithophores are single-celled algae coated with calcium carbonate plates called coccoliths, floating in the sunlit ocean layers. These organisms remove carbon from seawater, release oxygen, and generate more than 1.5 billion tonnes of calcium carbonate annually, capturing CO2 from the atmosphere and storing it in deep-sea sediments. Their plates contribute to chalk and limestone formations that chronicle Earth's climate past.
The announcement involves the Ruđer Bošković Institute in Zagreb, Croatia; the Lyell Centre at Heriot-Watt University in Edinburgh, UK; NORCE Norwegian Research Centre in Bergen, Norway; Marine and Environmental Sciences Centre (MARE) at the University of Lisbon in Portugal; and the International Nannoplankton Association (INA).
"Unlike other groups, they build intricate calcium carbonate plates that not only help draw down carbon dioxide from the atmosphere, but also transport it into deep ocean sediments, where it can be locked away for millennia," says Professor Alex Poulton of the Lyell Centre. "This biomineralization leaves behind an exceptional geological record, allowing us to study how they've responded to past climate shifts and better predict their future role. In short, their dual role as carbon pumps and climate archives makes them irreplaceable in understanding and tackling climate change."
At the Lyell Centre, the OceanCANDY team led by Poulton examines how coccolithophores sequester CO2 and responds to warmer, more acidic oceans. In Norway, Dr. Kyle Mayers' NORCE team studies their growth, predators, viruses, and ancient DNA from seafloor mud. "Coccolithophore interactions with viruses and grazers matter," Mayers says. "These links shape food webs and how the ocean stores carbon."
Croatia's Ruđer Bošković Institute, under Dr. Jelena Godrijan, explores bacterial interactions affecting carbon cycles. "In understanding coccolithophores, we're really uncovering the living engine of the ocean's carbon balance," Godrijan states. At MARE, Dr. Catarina V. Guerreiro investigates aerosol influences on their distribution from the Atlantic to the Southern Ocean. "We're connecting tiny chalky organisms to planetary carbon flows," she says. The INA links modern coccolithophores to fossils for climate reconstruction.
Climate change, by altering ocean temperature, chemistry, and nutrients, threatens these plankton and dependent ecosystems. "Coccolithophores are a vital part of the planet's climate system," notes Dr. Sarah Cryer from the CHALKY project. "They remind us that the smallest organisms can have the biggest impact." The initiative seeks to boost ocean literacy and policy focus on these invisible architects.