BIOLOGICAL PRODUCTION OF FORMALDEHYDE IN THE MARINE-ENVIRONMENT

We investigated biological production of low-molecular-weight (LMW) ca rbonyl compounds (e.g. formaldehyde, acetaldehyde, propanal, and glyox al) in axenic unialgal phytoplankton cultures of Skeletonema costatum and Heterocapsa pygmaea and in several natural plankton assemblages co llected at a coastal location in southeastern North Carolina. Of the c ompounds studied, formaldehyde was the only LMW carbonyl produced by t he biota with the exception of a single natural assemblage which also produced propanal. Similar patterns of biological production and utili zation of formaldehyde were observed during these culture experiments. Concentrations in filtrates increased while chlorophyll a concentrati ons remained relatively low, then declined as the organisms began thei r exponential growth phase. These oscillations in formaldehyde concent ration suggest biota are both generating and using formaldehyde concur rently. In situ depth profiles provided additional information regardi ng the turnover of formaldehyde. Concentrations were relatively high a t the surface and decreased to a minimum near the chlorophyll maximum, below which no consistent trends in formaldehyde concentration were o bserved. This study is the first known report of biological production of a LMW aldehyde in the marine environment.