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Release of extracellular organic carbon during a diatom bloom in Lake Mossö: molecular weight fractionation
Author(s) -
SöNDERGAARD MORTEN,
SCHIERUP HANSHENRIK
Publication year - 1982
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1982.tb00625.x
Subject(s) - fractionation , diatom , carbon fixation , gel permeation chromatography , carbon fibers , chemistry , extracellular , chromatography , molecular mass , dissolved organic carbon , environmental chemistry , botany , biochemistry , biology , photosynthesis , organic chemistry , materials science , enzyme , composite number , composite material , polymer
SUMMARY. Carbon fixation and release of extracellular organic carbon (EOC) during a diatom bloom were measured by the 14 C—technique. Release in light was always a small fraction (1.5‐6.0%) of total carbon fixation. Maximum values were found during the stationary phase of growth. A larger (15–50%) fraction of the inorganic carbon assimilated in the dark was released, although the absolute values were lower than in the light. Gel permeation chromatography showed that low molecular weight products (<700 daltons) dominated EOC released in the light. A shift toward more complex molecules (> 10,000 daltons) was found in the stationary phase. EOC released in the dark had almost equal amounts of low (< 700 daltons), intermediate (˜5,000 daltons) and high (< 10,000 daltons) molecular weight products. It is shown that with time the molecular weight composition of EOC shifted towards a predominance of larger molecules.