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

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 phenomena is obscured by the biological richness of these aggregates and lack of direct observation of their sedimentation physics. Utilizing a scale-free vertical tracking microscopy in field setting, here we present micro-hydrodynamic 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 halo around sinking aggregates. These invisible comet-tails slows down individual particles, dramatically increasing their residence time. Based on these findings, we construct a reduced order model for the Stokesian sedimentation of these mucus-embedded two-phase particles, paving the way towards a predictive understanding of marine snow., Sediment trap Sampling:
Data was collected while on board the R/V Endeavor during the cruise using a gravity machine (GM) [for details on the instrument see Krishnamurthy et al. Nat Methods 17, 1040–1051 (2020). https://doi.org/10.1038/s41592-020-0924-7]. We use sediment traps on RIPPLE1 Cruise (Cruise ID: EN667) with mesh size (50 μm) at 80 m depth in the Gulf of Maine on RV Endeavor [design of the net trap is given in Peterson et al. (2005) Limnol. Oceanogr. Methods, 3, doi:10.4319/lom.2005.3.520.]. The nets were recovered after 24 hrs and the exact times of the deployment and recovery are provided in the supplementary of material of the preprint: R. Chajwa et al. 2023 https://arxiv.org/abs/2310.01982. After the cod-end recovery, we pass the material through a quantitative splitter. We use a splitter that is modified from the on the basic design of Lamborg et al., 2008 https://doi.org/10.1016/j.dsr2.2008.04.011, to accommodate collection of twelve samples instead of eight and to allow..., , # Hidden Comet-Tails of Marine Snow Impede Ocean-based Carbon Sequestration

[https://doi.org/10.5061/dryad.v15dv4253](https://doi.org/10.5061/dryad.v15dv4253)

The Sedimentation and Particle Image Velocimetry (PIV) data of marine snow aggregates were acquired using a vertical tracking microscope, called Gravity Machine (GM) [for details on this instrument see Krishnamurthy et al. *Nat Methods* **17**, 1040–1051 (2020). [https://doi.org/10.1038/s41592-020-0924-7 ](https://doi.org/10.1038/s41592-020-0924-7 )]. The aggregates were collected using sediment trap in the Gulf of Maine [for details of the net trap design see Peterson et al. (2005) *Limnol. Oceanogr. Methods*, 3, doi:10.4319/lom.2005.3.520 ], with subsequent measurement of these aggregates on the GM made immediately upon retrieval of net trap, on board a research vessel R/V Endeavor. The microscope itself was mounted on a mechanical 2-axis gimbal to minimize the low-frequency background noise coming from the rock-and-roll dyna...