Changes in epilithic communities due to individual and combined treatments of zinc and snail grazing in stream mesocosms
Effects of 0.5 mg/liter zinc (Zn) and snail grazing (400 snails/m2) on density of dominant algal and protozoan taxa, epilithic glucose respiration, and ash-free dry weight (AFDW) were examined using established (12-day colonization) periphyton communities in flow-through stream mesocosms with four treatments (Zn, snails, Zn and snails, control) for 30 days. Grazing and Zn similarly reduced the abundance of 5 of 10 dominant algal taxa and AFDW during the first 10 days of treatment. Abundance of these taxa and AFDW in grazed (ambient Zn) treatments approached control levels after 10 days as the effect due to snails decreased. Decreasing temperatures may have reduced snail activity. Snails, Zn, and the combination of these treatments contributed to higher rates of glucose respiration per unit AFDW. Protozoan species abundance was reduced to less than half by Zn but was unaffected by snails. Although Zn and snails individually altered structural and functional aspects of this microbial community, the effects when both treatments were combined could not always be inferred from the individual effects. Testing individual and combined variables that affect periphyton with a corresponding assessment of population dynamics, biomass, and community functional attributes will enhance understanding of the overall effects of pollutants on periphyton communities.
- Research Organization:
- Virginia Polytechnic Institute, Blacksburg (USA)
- OSTI ID:
- 6599878
- Journal Information:
- Toxicol. Ind. Health; (United States), Vol. 4:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALGAE
SENSITIVITY
PROTOZOA
ZINC
TOXICITY
ECOLOGY
GLUCOSE
POPULATION DYNAMICS
SNAILS
WATER POLLUTION
ALDEHYDES
ANIMALS
AQUATIC ORGANISMS
CARBOHYDRATES
ELEMENTS
HEXOSES
INVERTEBRATES
METALS
MICROORGANISMS
MOLLUSCS
MONOSACCHARIDES
ORGANIC COMPOUNDS
PLANTS
POLLUTION
SACCHARIDES
560300* - Chemicals Metabolism & Toxicology