Sedgwick-rafter cell counts: a procedural analysis

Woelkerling, William J.; Kowal, Robert R.; Gough, Stephen B.

doi:10.1007/bf00040161

Cited by 55 publications

(31 citation statements)

References 8 publications

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“…Cells were counted in a Sedgwick rafter slide using standard methodology (Woelkerling et al, 1976). Biovolume was calculated by approximating cells to a sphere (Hillebrand et al, 1999).…”

Section: Cell Enumeration Cell Volume Chl a And Nutrient Analysismentioning

confidence: 99%

Impact of phosphorus quota and growth phase on carbon allocation inChlamydomonas reinhardtii: an FTIR microspectroscopy study

Dean

Nicholson

Sigee

2008

European Journal of Phycology

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Batch cultures of Chlamydomonas reinhardtii were used to study carbon allocation in relation to growth phase and phosphorus availability. Cultures were grown at initial phosphorus (PO 4 -P) concentrations of 500 mg l À1 (high-P) and 50 mg l À1 (low-P).Cellular carbon allocation was monitored using Fourier transform infrared (FTIR) microspectroscopy with the ratio of the band intensities at 1736 cm À1 (lipid) and the 1180-950 cm À1 region (carbohydrate) to 1652 cm À1 (amide I) used as an index of changing carbon balance. Cellular phosphorus concentrations (P quota) were measured by energy dispersive X-ray microanalysis (EDXRMA). Both treatments entered stationary phase on day 18. Increased cell counts in the high-P treatment (max. 3.0 Â 10 6 cells ml À1 at stationary phase) led to a rapid decrease in external P availability to <20 mg l À1 during early log phase, with a subsequent decrease in P quota from 0.5% to <0.1% DW. The fall of P quota to <0.1% led to an increase in the lipid/protein ratio (0.13 to 0.23) and carbohydrate/protein ratio (0.37 to 1.57), with ratios increasing further (lipid:protein 1.85; carbohydrate:protein 2.77) in late stationary phase. In the low-P treatment external P concentrations (<20 mg l À1 from day 1) restricted population growth (max. 0.75 Â 10 6 cells ml À1 at stationary phase). P quotas fell to <0.1% in early log phase, with the carbohydrate/protein ratio increasing from 0.15 to 3.7 and remaining high into stationary phase while the lipid/ protein ratio increased from 0.2 to 1.2. In both treatments increasing synthesis of lipid and carbohydrate storage products resulted in an increased cell volume. Transfer of P-deficient cells (late stationary) to fresh media led to a rapid stimulation of growth, a rapid reduction in lipid/protein and carbohydrate/protein ratios, and decreased cell volumes.

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“…Cells were counted in a Sedgwick rafter slide using standard methodology (Woelkerling et al, 1976). Biovolume was calculated by approximating cells to a sphere (Hillebrand et al, 1999).…”

Section: Cell Enumeration Cell Volume Chl a And Nutrient Analysismentioning

confidence: 99%

Impact of phosphorus quota and growth phase on carbon allocation inChlamydomonas reinhardtii: an FTIR microspectroscopy study

Dean

Nicholson

Sigee

2008

European Journal of Phycology

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“…Large filamentous algae were cut with scissors such that well-mixed aliquots of the sample could be obtained. Wet mounts on a ruled microscope slide (NeoSci, Nashua, New Hampshire) with a 16-mm 2 grid divided into eight 2-mm 2 squares were used to determine percent composition as described by Woelkerling et al (1976) and Schoen (1988). Soft algae within a 2-mm 2 square were observed at 100£, 400£, and 1000£ magnification, identified to the lowest taxon possible, and enumerated until at least 300 taxa were counted.…”

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confidence: 99%

Use of algae to assess the trophic state of a stream in Middle Tennessee

Lebkuecher

Tuttle

Johnson

et al. 2014

Journal of Freshwater Ecology

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Knowledge of the effects of nutrient concentration on the composition and structure of photoautotrophic periphyton is essential to understand the impact of eutrophication on shallow lotic systems. Reaches of Sulphur Fork Creek upstream and downstream of effluent from Springfield Wastewater Treatment Plant in Middle Tennessee were sampled to assess the effects of trophic state on characteristics of photoautotrophic periphyton, including composition of diatom and soft-algae assemblages. Pearson's correlation coefficient (r) for log 10 -transformed concentrations of soluble reactive phosphorus (log 10 [SRP]) to percent composition was significant for 4 of 63 soft-algae taxa sampled from cobbles. Five algae trophic indices (ATIs) to assess the effects of trophic state on soft-algae assemblages were developed using different taxon-trophic indicators which included: (1) r values for log 10 [SRP] to percent composition (ATI r ), (2) abundance-weighted averages of [SRP] (ATI A-WA [SRP] ), (3) abundance-weighted averages of log 10 [SRP] (ATI A-WA log [SRP] ), (4) weighted averages of log 10 [SRP] where the taxa occur, and (5) abundance-weighted ranks to phosphorus tolerance listed by the National Water-Quality Assessment Program. Eutrophication-induced impairment of Sulphur Fork Creek downstream of the effluent from the wastewater treatment plant was indicated by: (1) high concentrations of photoautotrophic periphyton, (2) low values for the pollution tolerance index of diatom assemblages, (3) positive values for the ATI r , and (4) high values for both the ATI A-WA [SRP] and ATI A-WA log [SRP] . Of the indices using soft-algae taxa evaluated, the ATI r exhibits the strongest and significant correlations to [SRP], [NO 2 C NO 3 nitrogen], and the pollution tolerance index of diatom assemblages. The ATI r accurately reflects the trophic state of the sites studied and provides a novel additional tool to evaluate the effects of nutrient concentration on the structure of photoautotrophic-periphyton assemblages.Keywords: periphyton; algae; diatoms; trophic state; nutrient enrichment; stream monitoring; indices of biotic integrity Introduction Nutrient enrichment is a primary basis of biological impairment of aquatic habitats worldwide (Irvine & Murphy 2009). Quantification of the impacts of eutrophication is required to monitor the efficacy of best management practices designed to improve integrity of nutrient-impaired waters (Smucker & Vis 2009). Increased concentration of chlorophyll a is a hallmark of eutrophication (Khan & Ansari 2005). Because chlorophyll a concentration is influenced by many abiotic and biotic characters of a stream reach, measurements of chlorophyll a concentration alone may not be adequate to demonstrate impairment by nutrient enrichment (Kurle & Cardinale 2011 Ecology, 2015 Vol. 30, No. 3, 349À376, http://dx.doi.org/10.1080/02705060.2014.951883 Ó 2014 Diatoms are the focus of most studies characterizing impacts of eutrophication on periphyton composition because more autecological informat...

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“…Several statistical studies of phytoplankton enumeration techniques have endorsed the counting of random fields over transects for increasing the accuracy and precision of within-chamber density estimates (Uehlinger, 1964;Woelkerling, Kowal & Gough, 1976). Although these studies were concerned primarily with other types of counting chambers, we strongly endorse the counting of random fields as the standard strategy for use with inverted microscope chambers.…”

Section: Discussionmentioning

confidence: 85%