Today, the Azolla filiculoides fern— with leaves the size of gnats — is found scattered throughout the world’s warm temperate and tropical regions. Some 50 million years ago, however, the planet was a much hotter place and Azolla grew as far north as the Arctic Ocean. Fossil records show that, fueled by abundant nitrogen and carbon dioxide, the fern formed thick mats across the entire ocean and crept onto the surrounding continents. Over the course of 1 million years, the plant pulled an estimated tens of trillions of tons of CO2 from the atmosphere, which scientists believe helped cool the planet to a climate more similar to what Earth has today.
For years, scientists have been studying whether Azolla filiculoids could help counteract rising greenhouse gas emissions and global temperatures. Researchers say sequencing the species’ genome, done by more than 40 scientists from around the world and supported partly by a crowdfunding campaign, will provide the first real clues as to how effective the plant would be combatting climate change. The research is published in the journal, Nature Plants.
Scientists are also interested in the plant’s ability to fix nitrogen for crops, and its resistance to insects. Azolla has a symbiotic relationship with the cyanobacteria Nostoc azollae, which live in special cavities inside Azolla’s leaves. The cyanobacteria captures nitrogen from the air and converts it into something the ferns — and surrounding plants — can use, eliminating the need for added nitrogen fertilizers.