Primary Production in Laboratory Streams 1,2

Abstract

Six laboratory streams are being used to study primary production and community respiration in simple communities under different environmental conditions. A photosynthesisrespiration chamber has been developed to perform expcrimcnts relating primary production to different environmental conditions and to verify primary production measurements made directly in the laboratory streams or in natural streams. Gross primary production in the six streams under 6,000 lux of illumination ranged from 2.4 to 4.7 g of oxygen per m2 per day. Community respiration ranged from 1.6 to 4.2 g of oxygen per m2 per day. The P/R ratios usually varied bctwccn 1.0 and 2.0. The relationship between illumination intensity and primary production was approximately linear between zero and 4,000 lux, and maximum photosynthetic rates were obtained at about 21,000 lux.

Pseudoreplication and the Design of Ecological Field Experiments

“…There is good evidence to show that replicate microcosms do not differ significantly with respect to levels of community metabolism (Abbott 1966 at Oregon State University], at least with respect to rates of community metabolism has been demonstrated (Mcintire et al 1964) . ...…”

“…He makes nodirect comment on whether replication of treatments is made unnecessary by such values, but in his later experimental work (Abbott 1967) he did not replicate his treatments. Mcintire et al ( 1964) likewise made no mention of the need for replication and failed to replicate treatments in a later experiment (Mcintire 1968).…”

Periphyton Production in an Appalachian Mountain Trout Stream

“…Enhancement of primary productivity by current has been demonstrated in a number of studies (e.g., Whitford 1960, Mcintire 1966a, b, Pfiefer and McDiffet 1975, Rodgers and Harvey 1976. Several productivity studies in a wide range of flowing waters have combined various continuous current chambers with gas exchange and pH methods for favorable results (Mcintire et al 1964, Thomas and O'Connell 1966, Bombowna 1972, Cushing and Rose 1970, Hansmann, Lane and Hall 1971, Ertl and Tomajka 1973, Pfeifer and McDiffett 1975, Marker 1976, Rodgers 1977, Bott et al 1978). …”

Stream Aufwuchs accumulation processes: Effects of ecosystem depopulation

“…In the ensuing years glass slides and other artificial substrates have been used to assess water pollution and study aspects of biomass accumulation in natural stream ecosystems (Butcher, 1932 ;Castenholz, 1960;Sladecek & Sladeckova, 1964 ;King & Ball, 1966;Cattaneo et al, 1975) . To further isolate ecological factors influencing Aufwuchs growth, many workers as well as this study have used experimental stream ecosystems in which selected variables including light, current, temperature, and toxicants may be controlled (McIntire et al, 1964 ;Warren & Davis, 1971 ;McIntire,1975 ;Rodgers, 1977) .…”