Just read about an interesting new paper on a study designed to estimate the amount of dissolved organic carbon (DOC) in the surface oceans.
UM [Univ. of Miami] researchers study vast carbon residue of ocean life
They compared measurements of DOC with a model of DOC production:
"The researchers discovered that the production of dissolved organic carbon at the ocean's surface could be accurately predicted by measuring the amount of nutrients arriving into the euphotic, or sunlit, zone.Here's an image of the results. Chlorophyll concentration on the left, DOC on the right.
The nutrients arrive there mostly by winter mixing and upwelling, and in turn support the growth of ocean plant life. From the arrival of nutrients to the surface ocean, they estimated the resulting plant growth and the production of residue, the DOC, from that growth. From those estimates, they built a map of DOC at the surface of the entire Atlantic Ocean."