ABSTRACT
Marine snow aggregates are fast sinking vehicles of organic and inorganic matter that often form at the decline of a phytoplankton bloom, accelerating the vertical downward flux of biologically fixed atmospheric carbon to the deep ocean. Marine snow also incorporates and transports marine contaminants such as microplastics and spilled oil into the ocean’s interior. During sinking through the water column, aggregates are subject to biological and physical transformation, determining the export efficiency of marine snow-associated matter. I will present results from laboratory incubations on heterotrophic microbial degradation and physical fragmentation of marine snow and marine oil snow, emphasizing the importance of small scale processes in millimeter-sized aggregates on large scale implications for the ocean’s elemental cycling.