Automated measurement of diatom size

Limnology and Oceanography: Methods
By: , and 

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Abstract

Size analysis of diatom populations has not been widely considered, but it is a potentially powerful tool for understanding diatom life histories, population dynamics, and phylogenetic relationships. However, measuring cell dimensions on a light microscope is a time-consuming process. An alternative technique has been developed using digital flow cytometry on a FlowCAM® (Fluid Imaging Technologies) to capture hundreds, or even thousands, of images of a chosen taxon from a single sample in a matter of minutes. Up to 30 morphological measures may be quantified through post-processing of the high resolution images. We evaluated FlowCAM size measurements, comparing them against measurements from a light microscope. We found good agreement between measurement of apical cell length in species with elongated, straight valves, including small Achnanthidium minutissimum (11-21 µm) and largeDidymosphenia geminata (87–137 µm) forms. However, a taxon with curved cells, Hannaea baicalensis (37–96 µm), showed differences of ~ 4 µm between the two methods. Discrepancies appear to be influenced by the choice of feret or geodesic measurement for asymmetric cells. We describe the operating conditions necessary for analysis of size distributions and present suggestions for optimal instrument conditions for size analysis of diatom samples using the FlowCAM. The increased speed of data acquisition through use of imaging flow cytometers like the FlowCAM is an essential step for advancing studies of diatom populations.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Automated measurement of diatom size
Series title Limnology and Oceanography: Methods
DOI 10.4319/lom.2012.10.882
Volume 10
Year Published 2012
Language English
Publisher Association for the Sciences of Limnology and Oceanography
Contributing office(s) National Water Quality Assessment Program
Description 9 p.
First page 882
Last page 890
Online Only (Y/N) N
Additional Online Files (Y/N) N