Hidden comet tails of marine snow impede ocean-based carbon sequestration

• 成果类型: Article
• 署名作者: Chajwa, Rahul; Flaum, Eliott; Bidle, Kay D.; Van Mooy, Benjamin; Prakash, Manu
• 署名单位: Stanford University; Stanford University; Stanford University; Stanford University; Stanford University; Rutgers University System; Rutgers University New Brunswick; Woods Hole Oceanographic Institution
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-10156
• DOI: 10.1126/science.adl5767
• 发表日期: 2024-10-01
• 关键词: sinking particles; settling velocities; organic particles; twilight zone; flux; DYNAMICS; rates; size; BEHAVIOR; export

摘要

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.