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Microbial heterotrophic utilization of dissolved organic matter in a piedmont stream
Author(s) -
KAPLAN LOUISA.,
BOTT THOMAS L.
Publication year - 1983
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.1365-2427.1983.tb00686.x
Subject(s) - dissolved organic carbon , microcosm , heterotroph , environmental chemistry , chemistry , organic matter , biomass (ecology) , environmental science , ecology , biology , bacteria , organic chemistry , genetics
SUMMARY.1 The microbial heterotrophic utilization of dissolved organic matter (DOM) was determined experimentally in microcosms using stream water and stream‐bed sediments from a third order reach of White Clay Creek (Pennsylvania, U.S.A.). 2 Sources of DOM for the experiments included White Clay Creek water at baseflow and stormflow and cold water extracts of jewel weed ( Impatiens capensis L.) and spicebush ( Linderu henzoin (L.) Blume). 3 The heterotrophic activity of the sediments was measured as uptake of the following: dissolved organic carbon (DOC), molecular weight fractions within the DOC pool, carbohydrates, amino acids and peptides, phenolics, and dissolved oxygen (DO), all in the overlying water. 4 Concentrations of adenosine triphosphate (ATP), and direct microscopic counts of bacteria were used to estimate bacterial biomass in the surface sediments. 5 The microcosm experiments showed that specific DOC molecular size classes and DOM functional groups were selectively removed from solution, exposure to one DOM source affected responses to a different DOM source and certain DOM sources were more readily utilized than others. 6 Continued exposure to a DOM source increased microbial heterotrophic activity (a condition which persisted even after removal of the DOM source for several days). 7 Rates of biotic DOC uptake ranged from 3.6 to 242.8 mg Cm ‐2 h ‐1 . 8 Indirect estimates of biosynthesis calculated from DOC and DO data ranged from 1.6 at baseflow and 2.6–61.2 at stormflow to as high as 192.6 mg C m ‐2 h ‐1 when the community was repeatedly exposed to enriched DOM sources. 9 The mean generation times of bacteria in sediments, determined from direct microscopy data, ranged from 12.5 to 46.2 h at 15°C.