Decomposition studies in two central Ontario lakes having surficial pHs of 4. 6 and 6. 6
The rates of cellulose breakdown, composition of detrital microflora, and density of bacterial populations were determined in the epilimnetic sediments and water columns of two poorly buffered, oligotrophic, Canadian Shield lakes having mean surficial pHs of 4.6 (Bat Lake) and 6.6 (Harp Lake). The decomposition rate was significantly lower in oxic sediment of the acidified lake than of the circumneutral lake, but water column rates were almost identical in the two lakes. These results are explained in terms of the groups of cellulolytic microorganisms which were observed by phase-contrast microscopy as being active at the different sites: fungi in Bat Lake water and Cytophaga-like bacteria in the water and sediment of Harp Lake. Cytophaga-like bacteria were also the main decomposers in Bat Lake sediment, but their activity was restricted at porewater pHs of <5.0. Acridine orange direct counts of bacteria in the top centimeter of sediment ranged from 3.7 x 10/sup 8/ to 1.0 x 10/sup 9/ per g, and counts in planktonic water samples ranged from 4.9 to 10/sup 5/ to 1.2 x 10/sup 6/ per ml. Bacterial densities at most sites decreased significantly from August to late October, but did not show a consistent pattern of differences related to pH.
- Research Organization:
- Univ. of Toronto, Ontario
- OSTI ID:
- 6937666
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Vol. 52:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACIDIFICATION
ENVIRONMENTAL EFFECTS
BACTERIA
CELLULOLYTIC ACTIVITY
POPULATION DENSITY
FUNGI
LAKES
ACID NEUTRALIZING CAPACITY
CANADA
DETRITUS
EXPERIMENTAL DATA
SEASONAL VARIATIONS
CHEMISTRY
DATA
ENZYME ACTIVITY
INFORMATION
MICROORGANISMS
NORTH AMERICA
NUMERICAL DATA
PLANTS
SURFACE WATERS
VARIATIONS
WATER CHEMISTRY
520200* - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)
560300 - Chemicals Metabolism & Toxicology