Enzymic and molecular analysis of microbial communities associated with lotic particulate organic matter

• Published in: Freshwater biology 1992-12, Vol.28 (3), p.393-404
• Main Authors: SINSABAUGH, ROBERT L., WEILAND, TIMOTHY, LINKINS, ARTHUR E.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Microbial ecology; Various environments (extraatmospheric space, air, water)
• ISSN: 0046-5070; 1365-2427
• DOI: 10.1111/j.1365-2427.1992.tb00597.x

SUMMARY 1. Most allochthonous plant detritus moves through stream ecosystems as fine particulate organic matter (FPOM), whose associated microbial communities, unlike those of coarse detritus, have received little scrutiny. 2. Benthic POM was collected from a fourth‐order boreal river and two first‐order tributaries in northern New York during July 1991, sorted it into eight size fractions ranging from 38 to >4000 μm, and assayed each fraction for ergosterol, DNA, and the activity of nine extracellular enzymes: β‐1, 4‐glucosidase, endocellulase, cellobiohydrolase, phenol oxidase, peroxidase, β‐N‐acetylglucosaminidase, acid phosphatase, alkaline phosphatase, and aryl sulphatase. In addition, DNA‐DNA hybridization was used to investigate the structural similarity of the microbial communities associated with the FPOM fractions. 3. Various enzymes showed distinct activity patterns in relation to particle size as well as among sites. Half of the possible pairwise correlations among enzyme variables were statistically significant, but no enzyme activities were correlated with biomass indices (DNA and ergosterol concentration). DNA‐DNA dot‐blot hybridizations suggested extensive structural similarity among the microbial communities associated with FPOM fractions. 4. Cluster analysis was used to compare microbial functional similarity, measured by enzyme assays, and structural similarity, measured by DNA—DNA hybridization. Comparison of cluster coefficients showed a weak correlation between community structural similarity and functional similarity (r= 0.51) with fifteen of eighteen fractions grouped within a narrow range of distance. 5. The results suggest a convergence in microbially mediated FPOM processing despite system‐level differences in litter and water quality.