Changes in the size and neutral aldose (NAld) composition of phytoplankton photosynthetic products during the early diagenetic process were experimentally examined using 13 C as a tracer. Most (94.7%) of the photosynthetically produced (P−) organic carbon (OC) was found to be particulate organic carbon (POC) after a 12‐h light incubation. An increase in the concentration of P‐dissolved organic carbon (DOC) was found after the...

Natural populations of diatoms were incubated for 4–12 h with H 13 CO 3 −1 . The production of particulate and dissolved fractions of organic carbon and neutral aldoses (NAld) was followed by gas chromatography/mass spectrometry. The extracellular production rate of dissolved organic carbon (DOC) ranged from 4.1% to 6.4% of total (particulate and dissolved) production rate. Glucose was a major component of the excreted dissolv...