Figure 3
Marine organic matter cycling corroborated by a proposed model.
Particulate organic matter (POM) in sea water is produced isotope-light by equilibrium fractionation during photosynthesis and is gradually processed by trophic level interactions in the ocean (weeks-to-years time-scale) to the isotope-heavy dissolved organic matter (DOM). Isotopically mixed sea spray organic matter (POA) undergoes kinetic fractionation by photochemistry and cloud-processing in the atmosphere on a weekly time-scale to isotope-heavy OM. Same scheme applies to secondary organic aerosol (SOA) formed directly or condensed on primary particles. Aged, processed and isotope-heavy OM is returned to the ocean contributing to the continuously recycled and replenished DOM pool. Ultimately the two end-member pools emerge – sequestered, isotope-light and recycled, isotope-heavy OM.
