Spectrophotometric Characteristics of Chlorophylls a and b and Their Phaeophytins in Ethanol

Department of Botany, University of Nijmegen, Nijmegen The Netherlands
Biochimica et Biophysica Acta (BBA) - Biophysics including Photosynthesis 11/1965; 109(2):448-453. DOI: 10.1016/0926-6585(65)90170-6


The absorption spectra of chlorophylls a and b in 96% ethanol, and of pheophytins a and b in 80% ethanol-0.01 N hydrochloric acid have been determined in comparison with known absorption coefficients.

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    • "Due to instrument availability, benthic chl a analysis was conducted using both spectrophotometric and fluorometric techniques. From each site, one of the three replicates was analysed on a spectrophotometer following a 24-hour cold ethanol (EtOH) extraction (Wintermans and De Mots 1965) using methods outlined by Bergmann and Peters (1980) and Webb et al. (1992). The remaining two replicates were analysed using a Turner 10AU fluorometer following a 7 minute digestion in 90% EtOH at 808C. "
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    ABSTRACT: Beavers (Castor spp.) are ecosystem engineers and important modifiers of freshwater ecosystems. They create impoundments that flood the surrounding landscape and modify the flow of materials through streams, thus potentially increasing nutrients, productivity and the availability of toxic methyl mercury (MeHg) to downstream food webs. Here we quantify food web-available MeHg in water, periphyton, and invertebrates collected from 15 streams up- and down-stream from beaver impoundments in the Rocky Mountain foothills of Western Canada. While nutrients, algal biomass, and total invertebrate standing stock were not significantly elevated below ponds, MeHg concentrations (average increase of 1.73) and percent of total Hg that was MeHg (average increase of 1.33) showed a trend of higher values in all compartments downstream and the difference was significant in predatory invertebrates. This suggests that beaver impoundments can increase the availability and subsequent uptake of MeHg by basal food web organisms even if their immediate influence on nutrients and resources is limited. As beaver populations continue to rebound, more research is needed to fully characterise the effects of beavers on nutrient and contaminant cycling under different biogeochemical conditions.
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    • "Chlorophylls a and b were determined on red and green cheek according to ( Wintermans and Mat , 1965 ) as follows : half gram of fresh peel was extracted by about 15 ml of 85% acetone and 0 . 5 g calcium carbonate , the mixture was filtered through a piece of cotton by using a glass funnel and the residue was washed with a small volume of acetone and brought up to 25 ml . "
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    • "Prior to GC-FAME, approximate lipid concentrations and injection volumes were estimated from chlorophyll contents. Chlorophyll content was quantified in ethanol extracts using the optical density at 654 nm and a specific absorbance coefficient of 39.8 L cm -1 g -1 (Wintermans and de Mots 1965). The chlorophyll/lipid mass ratio was taken as one (Janero and Barrnett 1981; Droppa et al. 1990; Kirchhoff et al. 2002; Kóta et al. 2002). "
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