Assessing Changes in Biomass of Riverbed Periphyton

Abstract

Periphytic biomass in a downriver riffle of the Grand River in Southern Ontario, Canada was measured with concrete-block glass slide samplers from May to December 1971. Average rate of accumulation of periphyton on glass slides was 266.2 mg/m2/day ash-free weight, 120.9 mg/m2/day carbon, 20.4 mg/mz/day nitrogen, or 1.11 mg/mZ/day chlorophyll a and on concrete blocks was 590.0 mg/mZ/day ash-free weight, 202.9 mg/mZ/day carbon, 22.8 mg/m2/day nitrogen, or 2.95 mg/ mz/day chlorophyll a. The standing biomass of periphyton on glass slides varied from a maximum of 21.6 g/m2 between May 28 and July 15 to a minimum of 0.7 g/m2 in December with an average of 8.6 g/m2. The biomass on concrete blocks ranged from a high of 132.5 g/m2 in August to a low of 29.9 g/m2 in October with a mean of 66.1 g/rnZ. The well established periphyton on concrete blocks towards the end of the study period was similar to that from native rocks with respect t o biomass, carbon and nitrogen contents, and ratios of biomass t o chlorophyll a. This suggests t h a t concrete blocks are a better substrate than glass slides for measuring riverbed periphyton.By comparing biomass of periphyton on slides and on concrete blocks, the average rate of loss of periphyton from concrete blocks was estimated to be 2.9 g/m'/day, representing 63% of the mean total accumulation rate of the periphyton. The magnitude of the estimated total loss and the high standing biomass of the periphyton on concrete blocks manifest the importance of the periphyton as a source of organic matter in the river. Contents

Periphyton growth and diatom community structure in a cooling water pond

“…The relationship between AFDW and chlorophyll a of periphytic matter was very similar to that found by Liaw & MacCrimmon (1978) . During colonization the chlorophyll a content decreased with increasing periphyton accumulation .…”

“…During colonization the chlorophyll a content decreased with increasing periphyton accumulation . Liaw & MacCrimmon (1978) attributed this finding to changes in physical factors, e .g., light and temperature. In Vasikkalampi pond this relationship between AFDW and chlorophyll a appeared to be related to changes in the proportion of animals associated with the periphytic material .…”

Benthic community metabolism in four temperate stream systems: An inter-biome comparison and evaluation of the river continuum concept

“…These parameters should be measured in studies of community metabolism because of their direct bearing on photosynthesis and respiration. When either the chemical or the geomorphic parameters were used with PAR, temperature, and chlorophyll a; the equations incorporating geomorphic parameters were slightly more precise and accounted for 83-98% of the variance 31 PA Liaw & MacCrimmon 1978Grzenda & Brehmer 1960Hornberger et al 1977Sumner & Fisher 1979Fisher & Carpenter 1976Fisher & Likens 1973Naiman 1983Naiman 1983Naiman 1983Naiman 1983Naiman 1983 This study a Data in parentheses converted from originally reported values using one or more of the following factors as necessary: P.Q. = 1.2, R.Q.…”

Efeitos da irradiância e da composição espectral da luz sobre o estabelecimento e desenvolvimento de comunidades de macroalgas lóticas em substratos artificiais

“…Exemplos de estudos ecológicos envolvendo a análise de comunidades de produtores associadas a substratos artificiais em ambientes lóticos são relativamente comuns na literatura mundial (Biggs, 1988;Liaw & Maccrimmon, 1978;Leland & Carter, 1985;Clifford et al, 1992;Barbee, 2005). Vários estudos semelhantes são encontrados para rios e riachos brasileiros (Lobo & BuselatoToniolli, 1985;Oliveira et al, 2002;Mendes & Barbosa, 2002;Fernandes & Esteves, 2003;Skinner & Coutinho, 2005;Lobo et al, 2004).…”