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Title: Protozoan grazing on bacteria at the sediment-water interface of an acidified lake

Abstract

Protozoan grazing on bacteria has been hypothesized to link the detrital and grazer food chains in aquatic ecosystems. The current study of protozoan bacterivory, evaluated methods, quantified bacterivory, and evaluated the role of protozoa at the sediment-water interface of an acidified lake ecosystem, Lake Anna, Virginia. Three limnetic methods for determining protozoan bacterivory were tested for applicability at the sediment-water interface. The eucaryote inhibitor, cycloheximide, was found unsatisfactory because it did not uniformly inhibit growth of target eucaryotes, and because it inhibited non-target anaerobic procaryotes. The filtration method was found to have limited application in sediment systems due to filtrational loss of particle-associated bacteria. The dilution method was tested for violations of its critical assumptions: bacterial growth is exponential; grazing mortality is proportional to the dilution factor; and bacterial growth rates are unaltered under experimental conditions. These assumptions were found not to be violated, and this method was used in subsequent grazing experiments. Carbon loading to the acidified arm of Lake Anna was 41 {times} 10{sup 6} g C {times} y{sup {minus}1}. This appears to be adequate carbon loading to support bacterial production and, in turn, protozoan bacterivory and production. Though there is no direct evidence that zooplankton graze onmore » protozoa in this system, however, there is sufficient protozoan production to support an additional trophic level.« less

Authors:
Publication Date:
Research Org.:
Virginia Univ., Charlottesville, VA (USA)
OSTI Identifier:
7152833
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph.D)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; AQUATIC ECOSYSTEMS; ECOLOGY; ACIDIFICATION; BACTERIA; EXPERIMENTAL DATA; FOOD CHAINS; LAKES; PRODUCTIVITY; PROTOZOA; SEDIMENT-WATER INTERFACES; ANIMALS; DATA; ECOSYSTEMS; INFORMATION; INTERFACES; INVERTEBRATES; MICROORGANISMS; NUMERICAL DATA; SURFACE WATERS; 540310* - Environment, Aquatic- Basic Studies- (1990-); 540320 - Environment, Aquatic- Chemicals Monitoring & Transport- (1990-)

Citation Formats

Tremaine, S C. Protozoan grazing on bacteria at the sediment-water interface of an acidified lake. United States: N. p., 1988. Web.
Tremaine, S C. Protozoan grazing on bacteria at the sediment-water interface of an acidified lake. United States.
Tremaine, S C. 1988. "Protozoan grazing on bacteria at the sediment-water interface of an acidified lake". United States.
@article{osti_7152833,
title = {Protozoan grazing on bacteria at the sediment-water interface of an acidified lake},
author = {Tremaine, S C},
abstractNote = {Protozoan grazing on bacteria has been hypothesized to link the detrital and grazer food chains in aquatic ecosystems. The current study of protozoan bacterivory, evaluated methods, quantified bacterivory, and evaluated the role of protozoa at the sediment-water interface of an acidified lake ecosystem, Lake Anna, Virginia. Three limnetic methods for determining protozoan bacterivory were tested for applicability at the sediment-water interface. The eucaryote inhibitor, cycloheximide, was found unsatisfactory because it did not uniformly inhibit growth of target eucaryotes, and because it inhibited non-target anaerobic procaryotes. The filtration method was found to have limited application in sediment systems due to filtrational loss of particle-associated bacteria. The dilution method was tested for violations of its critical assumptions: bacterial growth is exponential; grazing mortality is proportional to the dilution factor; and bacterial growth rates are unaltered under experimental conditions. These assumptions were found not to be violated, and this method was used in subsequent grazing experiments. Carbon loading to the acidified arm of Lake Anna was 41 {times} 10{sup 6} g C {times} y{sup {minus}1}. This appears to be adequate carbon loading to support bacterial production and, in turn, protozoan bacterivory and production. Though there is no direct evidence that zooplankton graze on protozoa in this system, however, there is sufficient protozoan production to support an additional trophic level.},
doi = {},
url = {https://www.osti.gov/biblio/7152833}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 1988},
month = {Fri Jan 01 00:00:00 EST 1988}
}

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