Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms

摘要: Lithogenic particles, such as desert dust, have been postulated to influence particulate organic carbon (POC) export the deep ocean by acting mineral ballasts. However, an accurate understanding and quantification of POC–dust association that occurs within upper is required in order refine "ballast hypothesis". In framework DUNE (a DUst experiment a low-Nutrient, low-chlorophyll Ecosystem) project, two artificial seedings were performed seven days apart large mesocosms. A suite optical biogeochemical measurements used quantify surface POC following simulated dust events low-nutrient, ecosystem. The successive led 2.3–6.7-fold higher flux than observed controlled simple linear regression analysis revealed lithogenic fluxes explained more 85% variance fluxes. On scale dust-deposition event, we estimated 42–50% strictly associated with particles (through aggregation most probably sorption processes). ballasting also likely impacted remaining fraction which resulted from fertilization effect. observations support hypothesis" provide quantitative estimation abiotically triggered deposition. this work, demonstrate strength "lithogenic pump" depends on conditions water column at time Based these observations, suggest pump could represent major component biological oceanic areas subjected intense atmospheric forcing.