Photoelectric Light-Scattering Photometer for Determining High Molecular Weights*

Brice, B. A.; Halwer, Murray; Speiser, R.

doi:10.1364/josa.40.000768

Cited by 372 publications

(64 citation statements)

References 16 publications

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“…Volume scattering is defined by Kirk (1994, p. 16) as "the radiant intensity in a given direction from a volume clement, dV, illuminated by a parallel beam of light, per unit of irradiance on the cross-section of the the volume, and per unit volume." Measurements of volume scattering were made with a Brice Phoenix model 2000 light-scattering photometer (Brice et al 1950). Spilhaus (1965) and Pak (1970) have discussed the accuracy and precision of the Brice Phoenix light-scattering photometer when used with seawater samples.…”

Section: Methodsmentioning

confidence: 99%

The 1991 coccolithophore bloom in the central North Atlantic. 1. Optical properties and factors affecting their distribution

Balch

Kilpatrick

Trees

1996

Limnology & Oceanography

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Optical scattering and absorption were measured in the central North Atlantic Ocean during a mesoscale bloom of the coccolithophorid Emiliania huxleyi. The chlorophyll-specific absorption was similar to previously measured levels for this species in laboratory cultures,. Suspended coccoliths were responsible for -80% of the total backscattering in the center of the bloom, and the greatest calcite-dependent backscattering was observed just below the base of the mixed layer. Areal maps of calcite-dependent backscattering and reflectance were similar because of the dominance of backscattering over absorption. Calculated reflectance at 440 and 550 nm reached -24%, which is slightly less than what has been observed previously in Gulf of Maine blooms. Total _scattering (b) was also calculated as the difference between beam attenuation and absorption. The ratio b, (backscattering divided by total scattering) was -0.01-0.02 at 440 and 550 nm at the most turbid parts of the coccolithophore bloom (b = l-3 m-l). As total scattering decreased below 1 m-l, bb increased. The behavior of b, was compared for coccolith-dominated vs. chlorophyll-dominated waters. Vertical profiles of calcite-dependent scattering, combined with satellite remote sensing data, were used to assess the factors responsible for vertical transport of calcite. The subsurface peak in calcite-dependent scattering did not result from detached coccoliths sinking but resulted either from plated coccolithophores sinking and then detaching their plates or from deep coccolithophores producing and detaching their plates in situ.

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Section: Methodsmentioning

confidence: 99%

The 1991 coccolithophore bloom in the central North Atlantic. 1. Optical properties and factors affecting their distribution

Balch

Kilpatrick

Trees

1996

Limnology & Oceanography

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“…aBrice Phoenix model 2000 light scattering photometer [Brice et al 1950] was used. Volume-scattering measurements were made as described by Balch et al [1996a].…”

Section: Soeciesmentioning

confidence: 99%

Optical backscattering by calcifying algae: Separating the contribution of particulate inorganic and organic carbon fractions

Balch¹,

Drapeau²,

Cucci³

et al. 1999

J. Geophys. Res.

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Abstract. Light scattering properties of biogenic CaCO 3 particles [particulate inorganic carbon (PIC)]were determined on cultured calcifying algae and field-derived CaCO3 particles. The particles were separated from particulate organic carbon (POC) with a flow cytometer, volume-scattering functions were measured with a laser light-scattering photometer, and particle composition was measured using atomic absorption spectrometry. Small calcite coccoliths were best sorted by gating on the ratio of horizontally polarized forward light scattering and vertically polarized forward light scattering; plated coccolithophores could be sorted by gating on side scattering and forward angle light scattering. Normalized volume-scattering functions for the culture-derived calcite particles varied by a factor of 2 for the different species. Backscattering cross sections (m 2 particle -•) for calcite particles varied by -35 times and were generally a function of size. Backscattering efficiencies were -2-4 times higher for cells with CaCO3 than without it. CaCO3-specific backscattering showed much less variability across various species; the calcite-specific backscattering coefficient varied by only -38% for both cultured coccolithophores and field-derived CaCO• particles. Organic carbon-specific backscattering of "naked" coccolithophores was highly consistent within all coccolithophores used in our experiments, as well as with values in the literature. Our results suggest that both POC and PIC can be optically estimated, the former by measuring backscattering of alecalcified phytoplankton as well as their size distribution, and the latter is proportional to acid-labile backscattering. These results show the feasibility of a rapid optical technique for measuring two biogeochemically important carbon fractions in the sea.

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“…(9), using the cylindrical cell furnished with the instrument. The symmetry of the envelope of the cell was checked with a fluorescein solution and the cell was calibrated with a Ludox solution (10,11).…”

Section: Materials a N D Methodsmentioning

confidence: 99%

Potato X Virus: Part Iii. Light Scattering Studies

Reichmann¹

1959

Can. J. Chem.

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Light scattering studies were made on a non-aggregated potato X virus preparation. The data are consistent with a cylindrical model 5400 A long having a molecular weight of 35x106. The weight average length of 4700 A was determined from the high angle measurements. The low value of the weight average length, as cornpared with the length of the most frequent particle from electron microscopy, is interpreted in terms of a slight tendency to aggregate side-by-side. T h e insignificant extent of this aggregation is demonstrated by a direct evaluation of the weight average diameter. The value of 109 A obtained is only 9%higher than the number average diameter reported in the literature.

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Photoelectric Light-Scattering Photometer for Determining High Molecular Weights*

Cited by 372 publications

References 16 publications

The 1991 coccolithophore bloom in the central North Atlantic. 1. Optical properties and factors affecting their distribution

The 1991 coccolithophore bloom in the central North Atlantic. 1. Optical properties and factors affecting their distribution

Optical backscattering by calcifying algae: Separating the contribution of particulate inorganic and organic carbon fractions

Potato X Virus: Part Iii. Light Scattering Studies

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