Year: 2025
Type: article
Abstract: One of Earth’s largest carbon fluxes is driven by particles made from photosynthetically fixed matter, which aggregate and sink into the deep ocean. While biodegradation is known to reduce this vertical flux, the biophysical processes that control particle sinking speed are not well understood. Here, we use a vertical millifluidic column to video-track single particles and find that biogels scavenged by particles during sinking significantly reduce the particles’ sinking speed, slowing them by up to 45% within one day. Combining observations with a mathematical model, we determine that the mechanism for this slowdown is a combination of increased drag due to the formation of biogel tendrils and increased buoyancy due to the biogel’s low density. Because biogels are pervasive in the ocean, we propose that by slowing the sinking of organic particles they attenuate the vertical carbon flux in the ocean. Sinking organic particles transport vast amounts of carbon to the deep ocean. This study shows that biogels scavenged during their descent can slow their sinking by up to 45% in one day, regulating a key process in the oceanic carbon cycle.
Source: Nature Communications
Institutions: Hebrew University of Jerusalem, ETH Zurich, Institute of Environmental Engineering, Ulsan National Institute of Science and Technology, Centre National de la Recherche Scientifique, Institut de Physique de Rennes, Université de Rennes, Institute for Molecular Systems Biology, University of Luxembourg
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $6,990
Funders: National Science Foundation, Simons Foundation, Gordon and Betty Moore Foundation, European Molecular Biology Organization, European Commission, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Fonds National de la Recherche Luxembourg, Council for Higher Education
Awards: Microscale investigation of key bacterial phenotypes enhancing collection by rising bubbles and aerial dispersal, BioEncounters – where physics encounters microbial ecology, G4157327457, G4206024285, G434337789, The role of ambient flow and physico-chemical microenvironment in determining the microstructure of the biofilm matrix, G8580053744, Roman Stocker Symbiosis in Aquatic Systems Initiative Investigator Award
OpenAlex ID: W4409208916