Journal ArticleHidden comet tails of marine snow impede ocean-based carbon sequestrationChajwa, Rahul; Flaum, Eliott; Bidle, Kay D; Van_Mooy, Benjamin; Prakash, Manu<p>Gravity-driven sinking of “marine snow” sequesters carbon in the ocean, constituting a key biological pump that regulates Earth’s climate. A mechanistic understanding of this phenomenon is obscured by the biological richness of these aggregates and a lack of direct observation of their sedimentation physics. Utilizing a scale-free vertical tracking microscopy in a field setting, we present microhydrodynamic measurements of freshly collected marine snow aggregates from sediment traps. Our observations reveal hitherto-unknown comet-like morphology arising from fluid-structure interactions of transparent exopolymer halos around sinking aggregates. These invisible comet tails slow down individual particles, greatly increasing their residence time. Based on these findings, we constructed a reduced-order model for the Stokesian sedimentation of these mucus-embedded two-phase particles, paving the way toward a predictive understanding of marine snow.</p>AAAS2024-10-1110556244Science38667180036-8075https://doi.org/10.1126/science.adl57672021032; 2025777; 2020878; 2020980National Science Foundation