Far below the ocean’s surface, millions of tiny particles fall through the water like a scene from a snow globe. But this isn’t anything like normal snow; this is “marine snow,” debris from tiny dead organisms like plankton and algae that floats down to the deep sea. Because carbon is one of the main chemical elements in living things, the ocean floor becomes coated in an ever-growing carbon-rich layer (sometimes peeking its head above water, like the White Cliffs of Dover.)
This deep sea layer is the largest carbon store on Earth. As increasing atmospheric carbon leads to rising temperatures, land-dwellers are beginning to wonder what role underwater buffers can play. A team of researchers at the University of Sydney studied core samples extracted from the ocean floor over the last 50 years. They built a computer model that simulates the formation and erosion of marine snow to recreate the growth of the deep sea carbon layers over the last 120 million years. They found that marine snow has actually increased over the last 50 million years, absorbing carbon and cooling the Earth’s climate enough to cause the formation of glaciers.
So, can marine snow continue to keep our planet on ice? Maybe. Planetary conditions 50 million years ago created an environment that supported the formation of deep-sea carbon stores, but present-day conditions might work against it. In a press release, study co-author Dietmar Muller, professor of geophysics at the University of Sydney, notes that as the oceans get more acidic, they lose their ability to store carbon effectively. Marine snow may end up being one part of a larger plan to keep our planet cool.
Managing Correspondent: Aparna Nathan
Original article: Sequestration and subduction of deep-sea carbonate in the global ocean since the Early Cretaceous – Geology
Media coverage: Marine Snow Has Cooled the Planet With Dead Plankton for Millions of Years – Atlas Obscura
What is Marine Snow? – University of Sydney
Image credit: NOAA Okeanos Explorer Program, MCR Expedition 2011