Assessment of optimum aquatic microcosm design for pollution impact studies

Technical Report · Sat Aug 01 04:00:00 EDT 1981

OSTI ID:6062168

Harte, J; Levy, D; Rees, J; Saegebarth, E

A series of experiments was carried out to evaluate optimum design and operating conditions for pelagic lake microcosms and to explore a possible use of such systems for toxicological testing. Criteria selected for microcosm optimization were realism and replicability of identically initiated microcosms. In the assessment studies, a number of different pelagic microcosm configurations were studied, including the size of the microcosm containers, the method of algal surface-growth prevention, and the degree of water mixing and aeration. In addition, the microcosm-lake comparisons were carried out in various seasons of the years to determine the influence of natural seasonal factors on the chemical and biological differences between the lakes and microcosms. In all but the smallest microcosms, surface-growth prevention removed size dependence. Chemical nutrients tracked well except during periods when nutrient inputs to the lake from the surrounding watershed were high. Good tracking of phytoplankton succession patterns was observed only when the physical conditions of the lake matched well with those in the laboratory system. In the decomposition studies, additions of dead organic matter to the lake microcosms were made, and the subsequent response of mineralization activity was measured. Highly replicable and interesting short-term behavior was seen, implying that protocols can be developed for microcosm testing of effects of toxicants on mineralization rates. On the basis of the microcosm assessment and decomposition studies, it was concluded that appropriate applications of pelagic microcosms are limited, and those applications that are most appropriate are delineated.

• Research Organization: Lawrence Berkeley Lab., CA (USA); Electric Power Research Inst., Palo Alto, CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6062168
• Report Number(s): EPRI-EA-1989; ON: DE81030674
• Country of Publication: United States
• Language: English

Related Subjects

520100 -- Environment
Aquatic-- Basic Studies-- (-1989)
520200* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AERATION
AQUATIC ECOSYSTEMS
AQUATIC ORGANISMS
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
DECOMPOSITION
DESIGN
ECOSYSTEMS
ENVIRONMENTAL IMPACTS
LAKES
LIMNOLOGY
MICROCOSMS
MINERALIZATION
MIXING
NUTRIENTS
OPTIMIZATION
ORGANIC MATTER
PHYTOPLANKTON
PLANKTON
POLLUTION
POPULATION DYNAMICS
PRODUCTIVITY
SEAS
SEASONAL VARIATIONS
SURFACE WATERS
TOXICITY
VARIATIONS
WATER POLLUTION