Abstract:
Small amounts of carbon from glucose and leucine added at natural
concentrations to seawater were biologically transformed to higher
molecular weight (MW) dissolved materials which persisted through six
months of incubation. These materials were resistant to biological
utilization: only 1 to 17% of the higher MW carbon was respired when
re-incubated with seawater microbial populations. Over the same time
span, 40 to 75% of the monomers were respired. In situ transformations
of biologically-available carbon may be important mechanisms for
the production of refractory dissolved organic carbon in the oceans.
