Gooey Marine Snow Boosts Carbon Transport, New Study Finds

Viscous Marine Snow Shuttles Six Times More Carbon to Deep Ocean

Marine snow particles with higher viscosity resist bacterial breakdown and sink significantly deeper, transporting more than six times as much carbon to the deep ocean compared to less viscous detritus, according to a study published on October 8, 2026, in the journal Science. Researchers at the University of California San Diego’s Scripps Institution of Oceanography and the University of Lincoln uncovered the mechanism governing this carbon sink disparity after developing a specialized visualization technique to observe live bacteria interacting with ocean mucus.

The Tech TL;DR:
• Gooey marine snow particles resist bacterial colonization and degradation far longer than low-viscosity particles.
• High-viscosity marine snow transports more than six times the amount of carbon into the deep ocean.
• New 3D confocal microscopy and fluorescent molecule methods mapped individual bacteria interacting with marine snow surfaces for the first time.

The Four-Year Search for the Mucoscape

Marine snow consists of tiny clumps of organic and inorganic detritus, including mucus, fecal matter, silt, and dead plankton, that continuously sink from the ocean surface to the seafloor. Scientists estimate that these showers transport more than 10 gigatons of carbon away from the surface every year. However, prior estimates indicated that only two gigatons reach depths sufficient for long-term storage spanning hundreds to thousands of years. Scripps Institution of Oceanography reported that the newly identified viscosity factor helps explain this discrepancy.

Observing individual microorganisms operating inside ocean slime presented a persistent technical roadblock. Bryce Inman, a postdoctoral scholar at Scripps when the project started in 2021, sought to visualize what he termed “the mucoscape.” Inman and microbiologist Farooq Azam spent four years attempting to track live bacteria interacting with the physical structure of marine snow without success. By 2025, the research team deployed a combination of 3D confocal microscopy and specialized fluorescent molecules. This setup allowed researchers to map the physical terrain of individual clumps, uncovering complex internal structures featuring bulges and crevasses smaller than a bacterium.

Bacteria Colonize Less Viscous Areas of Marine Snow

No two marine snow particles share identical molecular compositions or viscosity profiles. The Scripps team utilized their imaging breakthrough—detailed concurrently in a companion paper in Nature Communications—to determine how microbial populations navigate these sticky habitats. Bacteria successfully colonize less viscous areas near a particle’s outer surface with relative ease, but find interior, highly viscous regions impenetrable until enzymatic degradation breaks down the surrounding matrix.

Inman compared this dynamic to biological penetration, stating that bacteria latch onto less viscous portions but cannot reach denser zones until breaking them through, much like a worm navigating an apple where the flesh yields readily while the core remains tough. Laboratory experiments confirmed that high-viscosity marine snow particles require considerably more time to degrade and fragment. Coupled with computer simulations, the data demonstrates that these resilient, gooey particles retain their structural integrity longer during descent, allowing them to sink deeper and achieve a carbon sequestration capacity greater than six times that of less viscous counterparts.