Size and refractive index of individual marine particulates: a flow cytometric approach

Ackleson, Steven G.; Spinrad, Richard W.

doi:10.1364/ao.27.001270

Cited by 110 publications

(60 citation statements)

References 21 publications

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“…In brief, each data point resulted from sorting (via flow cytometry) a subset of cells in a preserved field sample away from the others and then sizing those cells with use of a Coulter Counter (Model ZM, Beckman-Coulter; see Cavender-Bares 1999). A fit to the data based on the equations of Bohren and Huffman (1983) for Mie theory, which is similar to the modeling done by Ackelson and Spinrad (1988), is shown in Fig. 2, along with dotted lines representing our estimate of 95% confidence intervals on predicting volume from FALS.…”

Section: Measurement Of Chlorophyll and Nutrients-chlorophyll Amentioning

confidence: 87%

“…In Li's (1994) pioneering study, forward-angle light scatter (FALS) was used directly as a proxy for cell volume. Although the two are related in phytoplankton (e.g., Olson et al 1989), the relationship is not constant over all size classes (e.g., Ackelson and Spinrad 1988;Gin 1996). More recent studies have tried to correct for this (Gin 1996;Gin et al 1999), albeit still imperfectly, by calibrating the FALS signal with use of laboratory cultures and field populations that have been filter fractionated.…”

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confidence: 99%

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Microbial size spectra from natural and nutrient enriched ecosystems

Cavender-Bares

Rinaldo

Chisholm

2001

Limnology & Oceanography

106

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Microbial size spectra, including bacteria through nanophytoplankton, were measured by use of flow cytometry across the western north Atlantic Ocean and during two nutrient enrichment studies: bottle enrichments in the Sargasso Sea and an in situ iron enrichment in the equatorial Pacific (IronEx II). Spectral shapes, or the relative conformity to a function described by a power law, ranged from smooth and log linear during the spring bloom in the Sargasso Sea to being distinctly non-log linear in coastal waters. Overall, the individual spectra within large regions characterized by similar ecological conditions showed remarkable consistency, inviting speculation that powerful organizing mechanisms are at work in these communities. Moreover, the ensemble average of all of the spectra along the transect displays clear power-law behavior. Slopes ranged from Ϫ1.0, in which biomass was equally distributed between all size classes, to Ϫ1.4, in which proportionally more biomass was contained in smaller size classes; there was no clear relationship between nutrient concentrations and spectral slopes over the entire data set. Species succession in nutrient-enriched bottles caused spectra to evolve from relatively smooth power laws to distributions showing preferred sizes (i.e., nonlinear on a log-log plot). The IronEx II spectra, however, remained similar over the course of the experiment. It could be that the elimination of bottle effects in this experiment buffered the system in ways that maintained the size structure of the microbial community over the size range we measured. Our results suggest conditions that lead to log-linear size distributions; these should be verified over a broader range of scales and environments.Size spectra, which display the relative abundance of organisms of different sizes, convey a synoptic image of ecological communities that is taxon independent. As such, they have been attractive to ecological theorists and have been the subject of periodic interest in marine ecology for the past 30 yr. Sheldon et al. (1972Sheldon et al. ( , 1977 recognized the predictive powers of size spectra, suggesting that fish stocks could be predicted if the planktonic size spectrum were known. Moreover, a spectral approach offers potential for enhancing ecosystem models (Gin et al. 1998) AcknowledgementsWe thank the captain and crew of the R/V Oceanus, who facilitated the collection of the transect data through challenging weather conditions. We thank M. Durand and R. Greene for help developing the Mie fit to our calibration data. We also thank R. Olson and L. Moore for helpful comments on earlier drafts of this manuscript and J. Rodríguez and an anonymous reviewer for valuable critical comments.

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Section: Measurement Of Chlorophyll and Nutrients-chlorophyll Amentioning

confidence: 87%

mentioning

confidence: 99%

Microbial size spectra from natural and nutrient enriched ecosystems

Cavender-Bares

Rinaldo

Chisholm

2001

Limnology & Oceanography

106

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“…The regression equation was y = 0.094 + 0.013x; r2 = 0.50, y1 = 130, P < 0.005. be used to calculate mixing rates in surface Distribution of mean cell size forward light waters in the same way as proposed for oth-scatter) -Light scattering by particles is not er photoadaptive processes (Harris 1980; simple to interpret; its angular intensity dis- Lewis et al 1984; Welschmeyer and Hoepff-tribution at a given wavelength is deterner 1986; Cullen and Lewis 1988). We have mined by a complex interaction between done simple laboratory experiments de-size, shape, and refractive index (Van de signed to put a time scale on photoaccliHulst 1957; Ackleson and Spinrad 1988). mation in Synechococcus (Fig.…”

Section: Distributionmentioning

confidence: 92%

Pigments, size, and distributions of Synechococcus in the North Atlantic and Pacific Oceans

et al. 1990

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Dual-beam flow cytometry was used to analyze the distribution and optical characteristics of Synechococcus in the North Atlantic and Pacific Oceans. The depth range over which Synechococcus cells were abundant was related to the depth of the nitrite maximum and the chlorophyll maximum, but was not significantly correlated with the depth of the surface isothermal layer. Dual-beam analysis of chromophore pigment types revealed that the majority of the populations were of the high-urobilin type; low-urobilin types, similar to the isolate WH7803, were found only in coastal waters where they almost always co-occurred with high-urobilin strains.Phycoerythrin fluorescence intensity per cell increased dramatically with depth in the lower euphotic zone at all stations; at some open-ocean stations, very deep cells were as much as 100 times brighter than those at the surface. The maximal fluorescence intensity per cell was about the same at the coastal and oceanic stations, and the depth of maximal fluorescence was closely related to the depth of the nitrite maximum. At most stations, fluorescence per cell was constant throughout the mixed layer, but at some open-ocean stations it decreased continuously to the surface. The latter pattern suggests that mixing rates in these areas are slow relative to the abilities of the cells to photoacclimate. A distinct diel pattern in forward-angle light scatter was observed in cells in the mixed layer over vast regions, which we hypothesize to be coupled to growth of the cells during daylight hours.

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“…Microscopes, flow cytometers (Ackleson and Spinrad 1988), Coulter counters (Sheldon and Parsons 1967), and FlowCAMs (Sieracki et al 1998) are all possible instruments for producing such data. Their strengths and weaknesses are discussed below (see "Discussion").…”

Section: Size-dependent Dilution Methodsmentioning

confidence: 99%

Estimating size‐dependent growth and grazing rates and their associated errors using the dilution method

Taniguchi

Franks

Landry

2012

Limnology & Ocean Methods

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Size-dependent properties are pervasive in nature but difficult to measure for natural communities. Here, we develop a technique to estimate size-specific phytoplankton growth and grazing rates based on the two-point dilution method, enhanced by the acquisition of the size spectra of the phytoplankton in the samples. We describe a way to estimate standard deviations associated with the rate estimates, which can be applied either to the size-dependent or total community rates. We tested the accuracy of rates estimated using the size-dependent dilution method by applying it to dilution experiments simulated using a complex size-structured ecosystem model. The strong agreement between model and size-dependent dilution method rates (two-sample Kolmogorov-Smirnov test, P = 1) supports the accuracy of this new technique. Because size-dependent rates vary with the size interval over which they are calculated, we display the size-dependent growth and grazing rates and their standard deviations as a function of the size interval. This technique easily allows the assessment of rates for any size class of interest. Finally, we apply the size-dependent dilution method to data collected in the equatorial Pacific. There is a general agreement between size-based and previously published taxonomic-based rates, with differences reflecting the extent to which size classes are mixtures of taxa. The use of the size-dependent dilution method will provide new insights into the structure and dynamics of planktonic communities. Future applications of this method to other natural communities will help in assessing the size-dependencies of phytoplankton growth and grazing rates in their environments.

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Size and refractive index of individual marine particulates: a flow cytometric approach

Cited by 110 publications

References 21 publications

Microbial size spectra from natural and nutrient enriched ecosystems

Microbial size spectra from natural and nutrient enriched ecosystems

Pigments, size, and distributions of Synechococcus in the North Atlantic and Pacific Oceans

Estimating size‐dependent growth and grazing rates and their associated errors using the dilution method

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