Particle size measurement of diatoms with inference of their properties: comparison of three techniques
Diatom-rich sediments are common in several oceanic regions, especially the Southern Ocean. Some of these are strongly affected by bottom currents and are expected to be sorted by the flow. Examination of data on diatoms' response by instruments commonly used for size measurement is presented h...
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ftnerc:oai:nora.nerc.ac.uk:15016 2023-05-15T18:25:52+02:00 Particle size measurement of diatoms with inference of their properties: comparison of three techniques Pugh, Robert McCave, I. Nick 2011 http://nora.nerc.ac.uk/id/eprint/15016/ http://jsedres.geoscienceworld.org/cgi/content/abstract/81/8/600 unknown Society for Sedimentary Geology Pugh, Robert; McCave, I. Nick. 2011 Particle size measurement of diatoms with inference of their properties: comparison of three techniques. Journal of Sedimentary Research, 81 (8). 600-610. https://doi.org/10.2110/jsr.2011.43 <https://doi.org/10.2110/jsr.2011.43> Marine Sciences Biology and Microbiology Publication - Article PeerReviewed 2011 ftnerc https://doi.org/10.2110/jsr.2011.43 2023-02-04T19:29:35Z Diatom-rich sediments are common in several oceanic regions, especially the Southern Ocean. Some of these are strongly affected by bottom currents and are expected to be sorted by the flow. Examination of data on diatoms' response by instruments commonly used for size measurement is presented here. Diatoms are silt- to fine sand-size, filigree silica structures of many shapes with high porosity, thus both the bulk density and shape strongly influence the "size" that is calculated from measurements. We document the particle size of diatoms measured by instruments based on settling velocity (Sedigraph), electrical resistance pulse counting (Coulter counter), and laser diffraction (Malvern laser sizer). The Malvern laser consistently measures the largest diameters, followed by the Coulter counter and then settling-based techniques. Relationships between these inferred sizes (all expressed as quartz-equivalent spherical diameters) have implications for the physical properties of diatom tests. Earlier work has demonstrated that laser diffraction responds to the particles' external projected area. The effects of both low effective density and irregular shape of diatoms (compared with terrigenous grains) on their settling velocity causes the Sedigraph to indicate relatively small diameters. Shape effects are less pronounced for quasi-spherical diatom species. The Coulter counter records the diatoms' solid volume and is relatively unaffected by their density or shape. The measurement of different physical parameters by these instruments offers a basis for estimation of diatom porosity (fluid-occupied volume within the test). Measurements of the external diameter and solid volume allow estimates of porosity Phi. For (laser) sizes > 20 mu m this Phi = 75-95%, which can be quite well modeled as a perforated spherical shell of wall thickness similar to 1-1.5 mu m. For paleocurrent interpretations, a settling-based technique makes Sedigraph measurements of particle size the most useful, but the visual size is best given ... Article in Journal/Newspaper Southern Ocean Natural Environment Research Council: NERC Open Research Archive Southern Ocean Coulter ENVELOPE(-58.033,-58.033,-83.283,-83.283) Journal of Sedimentary Research 81 8 600 610 |
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Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Marine Sciences Biology and Microbiology |
spellingShingle |
Marine Sciences Biology and Microbiology Pugh, Robert McCave, I. Nick Particle size measurement of diatoms with inference of their properties: comparison of three techniques |
topic_facet |
Marine Sciences Biology and Microbiology |
description |
Diatom-rich sediments are common in several oceanic regions, especially the Southern Ocean. Some of these are strongly affected by bottom currents and are expected to be sorted by the flow. Examination of data on diatoms' response by instruments commonly used for size measurement is presented here. Diatoms are silt- to fine sand-size, filigree silica structures of many shapes with high porosity, thus both the bulk density and shape strongly influence the "size" that is calculated from measurements. We document the particle size of diatoms measured by instruments based on settling velocity (Sedigraph), electrical resistance pulse counting (Coulter counter), and laser diffraction (Malvern laser sizer). The Malvern laser consistently measures the largest diameters, followed by the Coulter counter and then settling-based techniques. Relationships between these inferred sizes (all expressed as quartz-equivalent spherical diameters) have implications for the physical properties of diatom tests. Earlier work has demonstrated that laser diffraction responds to the particles' external projected area. The effects of both low effective density and irregular shape of diatoms (compared with terrigenous grains) on their settling velocity causes the Sedigraph to indicate relatively small diameters. Shape effects are less pronounced for quasi-spherical diatom species. The Coulter counter records the diatoms' solid volume and is relatively unaffected by their density or shape. The measurement of different physical parameters by these instruments offers a basis for estimation of diatom porosity (fluid-occupied volume within the test). Measurements of the external diameter and solid volume allow estimates of porosity Phi. For (laser) sizes > 20 mu m this Phi = 75-95%, which can be quite well modeled as a perforated spherical shell of wall thickness similar to 1-1.5 mu m. For paleocurrent interpretations, a settling-based technique makes Sedigraph measurements of particle size the most useful, but the visual size is best given ... |
format |
Article in Journal/Newspaper |
author |
Pugh, Robert McCave, I. Nick |
author_facet |
Pugh, Robert McCave, I. Nick |
author_sort |
Pugh, Robert |
title |
Particle size measurement of diatoms with inference of their properties: comparison of three techniques |
title_short |
Particle size measurement of diatoms with inference of their properties: comparison of three techniques |
title_full |
Particle size measurement of diatoms with inference of their properties: comparison of three techniques |
title_fullStr |
Particle size measurement of diatoms with inference of their properties: comparison of three techniques |
title_full_unstemmed |
Particle size measurement of diatoms with inference of their properties: comparison of three techniques |
title_sort |
particle size measurement of diatoms with inference of their properties: comparison of three techniques |
publisher |
Society for Sedimentary Geology |
publishDate |
2011 |
url |
http://nora.nerc.ac.uk/id/eprint/15016/ http://jsedres.geoscienceworld.org/cgi/content/abstract/81/8/600 |
long_lat |
ENVELOPE(-58.033,-58.033,-83.283,-83.283) |
geographic |
Southern Ocean Coulter |
geographic_facet |
Southern Ocean Coulter |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
Pugh, Robert; McCave, I. Nick. 2011 Particle size measurement of diatoms with inference of their properties: comparison of three techniques. Journal of Sedimentary Research, 81 (8). 600-610. https://doi.org/10.2110/jsr.2011.43 <https://doi.org/10.2110/jsr.2011.43> |
op_doi |
https://doi.org/10.2110/jsr.2011.43 |
container_title |
Journal of Sedimentary Research |
container_volume |
81 |
container_issue |
8 |
container_start_page |
600 |
op_container_end_page |
610 |
_version_ |
1766207561460088832 |