Depth distribution of bacterial production in a stratified lake with an anoxic hypolimnion
The purpose of this study was to determine the depth distribution of bacterial biomass and production in a stratified lake and to test techniques to measure bacterial production in anaerobic waters. Bacterial abundance and incorporation of both (/sup 3/H)thymidine and (/sup 3/H)leucine into protein were highest in the metalimnion, at the depth at which oxygen first became unmeasurable. In contrast, (/sup 3/H)thymidine incorporation into DNA was highest in the epilimnion. Recovery of added (/sup 3/H)DNA was about 90% in waters in which the portion of (/sup 3/H)thymidine incorporation into DNA was about 40%. At least some obligate anaerobic bacteria were capable of assimilating thymidine since aeration of anaerobic hypolimnion waters substantially inhibited thymidine incorporation. The depth profile of bacterial production estimated from total thymidine and leucine incorporation and the frequency of dividing cells were all similar, with maximal rates in the metalimnion. However, estimates of bacterial production based on frequency of dividing cells and leucine incorporation were usually significantly higher than estimates based on thymidine incorporation (using conversion factors from the literature), especially in anaerobic hypolimnion waters. These data indicate that the thymidine approach must be examined carefully if it is to be applied to aquatic systems with low oxygen concentrations. The results also indicate that the interface between the aerobic epilimnion and anaerobic hypolimnion is the site of intense bacterial mineralization and biomass production which deserves further study.
- Research Organization:
- Univ. of Georgia, Athens
- OSTI ID:
- 6847909
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Vol. 52:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
BACTERIA
POPULATION DYNAMICS
PRODUCTIVITY
LEUCINE
BIOCHEMICAL REACTION KINETICS
THYMIDINE
ANAEROBIC CONDITIONS
DEPTH
DNA
INHIBITION
LAKES
MINERALIZATION
SPATIAL DISTRIBUTION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINO ACIDS
AZINES
CARBOXYLIC ACIDS
DIMENSIONS
DISTRIBUTION
HETEROCYCLIC COMPOUNDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MICROORGANISMS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
REACTION KINETICS
RIBOSIDES
SURFACE WATERS
550701* - Microbiology- Tracer Techniques
520200 - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)