Size distribution of planktonic autotrophy and microheterotrophy in DeGray Reservoir, Arkansas
Naturally occurring assemblages of phytoplankton and bacterioplankton were radiolabelled with sodium /sup 14/C-bicarbonate and sodium /sup 3/H-acetate and size fractionated to determine the size structure of planktonic autotrophy and microheterotrophy in DeGray Reservoir, an oligotrophic impoundment of the Caddo River in south-central Arkansas. Size distributions of autotrophy and microheterotrophy were remarkably uniform seasonally, vertically within the water column, and along the longitudinal axis of the reservoir despite significant changes in environmental conditions. Planktonic autotrophy was dominated by small algal cells with usually >50% of the photosynthetic carbon uptake accounted for by organisms <8.0 ..mu..m. Microheterotrophic activity in the 0.2- to 1.0-..mu..m size fraction, presumably associated with free-living bacterioplankton not attached to suspended particles, usually accounted for >75% of the planktonic microheterotrophy. Longitudinal patterns in autotrophic and microheterotrophic activities associated with >3-..mu..m and >1-..mu..m size fractions, respectively, suggest an uplake to downlake shift from riverine to lacustrine environmental influences within the reservoir. 83 references, 7 figures.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6501739
- Report Number(s):
- CONF-8310318-1; ON: DE85000923
- Resource Relation:
- Conference: DeGray lake research symposium, Arkadelphia, AR, USA, 4 Oct 1983; Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
Similar Records
Size distribution of autotrophy and microheterotrophy in reservoirs: implications for foodweb structure
Modest net autotrophy in the oligotrophic ocean
Related Subjects
BACTERIA
METABOLISM
PHYTOPLANKTON
AUTOTROPHS
CARBON 14
EXPERIMENTAL DATA
SEASONAL VARIATIONS
SIZE
TRACER TECHNIQUES
TRITIUM
WATER RESERVOIRS
AQUATIC ORGANISMS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON ISOTOPES
DATA
EVEN-EVEN NUCLEI
HYDROGEN ISOTOPES
INFORMATION
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MICROORGANISMS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
PLANKTON
RADIOISOTOPES
SURFACE WATERS
VARIATIONS
YEARS LIVING RADIOISOTOPES
520100* - Environment
Aquatic- Basic Studies- (-1989)