Assessment of FlowCam technology as a potential tool for rapid semi-automatic analysis of lacustrine Arcellinida (testate lobose amoebae)

Abstract This study assessed the possibility of replacing conventional microscopic methods of species-level identification and quantification of Arcellinida with a more rapid method utilizing the FlowCam® with VisualSpreadsheet® (FCVS; Fluid Imaging Technologies, Inc.). Arcellinida are an established group of benthic bioindicators of water and sediment quality in lakes. The use of Arcellinida proxy analysis in lakes and peatlands has dramatically increased since the 1980s, but the labor-intensive nature of identifying and quantifying Arcellinida through microscopy limits the number of samples analyzed. A flow cytometer and microscope with machine learning software has been used to enhance the speed of micropaleontological analysis for some groups (e.g., diatoms), but the potential of using the instrument to analyze Arcellinida in lake sediments has not previously been assessed. The FCVS was assessed here as a method of rapidly analyzing Arcellinida by comparing the results obtained by FCVS with results previously obtained through conventional microscopy in a 2016 study, using the same 46 sediment-water interface samples collected from three quadrats (1–3) in Wightman Cove, Oromocto Lake, New Brunswick, Canada. The FCVS was found to be most suitable for categorizing taxa as morpho-groups rather than using conventional taxonomic species. Therefore, results of the 2016 study were reclassified at the morphological level to facilitate comparison. Results of cluster analysis and Bray–Curtis dissimilarity matrix (BCDM) analysis showed that arcellinidan assemblages obtained through conventional microscopy and FCVS were comparable. Analysis using FCVS reduced operator analysis time by approximately 45%. FCVS shows potential as a reliable method for more rapid analysis of lacustrine Arcellinida, particularly for very large sample data sets; however, FCVS technology can only resolve Arcellinida at the morphological level, meaning that conventional microscopy methods are required if finer species-level taxonomic results are required.