An Assessment of Sub-Meter Scale Spatial Variability of Arcellinida (Testate Lobose Amoebae) Assemblages in a Temperate Lake: Implications for Limnological Studies

Abstract

Arcellinida (testate lobose amoebae), a group of benthic protists, were examined from 46 sediment-water interface samples collected from oligotrophic Oromocto Lake, New Brunswick, Canada. To assess (1) assemblage homogeneity at a sub-meter spatial scale and (2) the necessity for collecting samples from multiple stations during intra-lake surveys; multiple samples were collected from three stations (quadrats 1, 2, and 3) across the north basin of Oromocto Lake, with quadrat 1 (n = 16) being the furthest to the west, quadrat 2 (n = 15) situated closer to the center of the basin, and quadrat 3 (n = 15) positioned 300 m south of the mouth of Dead Brook, an inlet stream. Results from cluster analysis and non-metric multidimensional scaling (NMDS) analysis identified two major Arcellinida assemblages, A1 and A2, the latter containing two sub-assemblages (A2a and A2b). Redundancy analysis and variance partitioning results indicated that seven statistically significant environmental variables (K, S, Sb, Ti, Zn, Fe, and Mn) explained 41.5% of the total variation in the Arcellinida distribution. Iron, Ti and K, indicators of detrital runoff, had the greatest influence on assemblage variance. The results of this study reveal that closely spaced samples (~ 10 cm) in an open-water setting are comprised of homogenous arcellinidan assemblages, indicating that replicate sampling is not required. The results, however, must be tempered with respect to the various water properties and physical characteristics that comprise individual lakes as collection of several samples may likely be necessary when sampling multiple sites of a lake basin characterized by varying water depths (e.g., littoral zone vs. open water), or lakes impacted by geogenic or anthropogenic stressors (e.g., eutrophication, or industrial contamination).

Testate Amoeba Functional Traits and Their Use in Paleoecology

“…Arcellinida are mostly restricted to benthic habitats, but species with at least a partial planktic habit have been documented (Schönborn, 1962;Medioli et al, 1987;Yu et al, 2014). A large body of research has been produced that has documented the complex community responses of Arcellinida in these subenvironments, and due to the large number of environmental variables typical of lacustrine systems considerable intra-lake and inter-lake assemblage variability has been observed (Patterson, 1996;Roe et al, 2010;Nasser et al, 2016Nasser et al, , 2020aSteele et al, 2018;Cockburn et al, 2020). There has been considerable taxonomic confusion within the Arcellinida due to a historical proliferation of new species as a result of the considerable morphological variability observed within some taxa, and the common practice of describing new species within a regional context with little consideration of research elsewhere, (e.g., Medioli et al, 1990;Wanner and Meisterfeld, 1994;Bobrov et al, 1999;Wanner, 1999;Charman et al, 2000).…”

“…The increase in the number of functional taxonomic units afforded by deployment of the 'strain' concept has permitted lacustrine researchers to more effectively explore the spatiotemporal effects of various sedimentological, geochemical, and organic variables, as well as the influence of lacustrine parameters on community structure and dynamics (Collins et al, 1990;Patterson, 1996;Reinhardt et al, 1998;Kumar and Patterson, 2000;Escobar et al, 2008;Neville et al, 2010;Roe et al, 2010;Nasser et al, 2016;Gavel et al, 2018;Steele et al, 2018;Cockburn et al, 2020). For instance, many studies have confirmed the sensitivity of arcellinidan communities to variability in pH (e.g., Asioli et al, 1996;Kumar and Patterson, 2000;Escobar et al, 2008;Neville et al, 2010;Patterson et al, 2013).…”

Intra-lake response of Arcellinida (testate lobose amoebae) to gold mining-derived arsenic contamination in northern Canada: Implications for environmental monitoring

“…All sub-samples had statistically significant numbers of Arcellinida tests and were thus included in subsequent statistical analyses. Reinhardt et al (1998), Roe, Patterson & Swindles (2010), Patterson et al (2013), Steele et al (2018) and the extensive online Microworld database (Siemensma, 2019). Because lacustrine arcellinidan species can display considerable environmentally-controlled infraspecific morphological variability (e.g., Medioli & Scott, 1983), the accepted practice has been to designate informal infrasubspecific "strain" names for these ecophenotypes (Asioli, Medioli & Patterson, 1996;Reinhardt et al, 1998;Patterson & Kumar, 2002).…”

“…While infrasubspecific level designations have no status under the International Zoological Code of Nomenclature (art. 45.5; 4th edition, 1999; International Commission on Zoological Nomenclature, 1999), they have been extensively used in the literature for defining environmentally significant populations within lacustrine environments (e.g., Reinhardt et al, 1998;Roe, Patterson & Swindles, 2010;Steele et al, 2018). Scanning electron microscope images of common species and strains were obtained using a Tescan Vega-II XMU VP scanning electron microscope (SEM) in the Carleton University Nano Imaging Facility.…”

Understanding the impact of millennial to sub-decadal climate and limnological change on the stability of As in lacustrine sediments

“…Arcellinida (testate lobose amoeba), are a group of protists that agglutinate a test from surrounding minerogenic material or scavenged skeletal material(Patterson and Kumar 2000a). Arcellinida are ubiquitous in freshwater(Patterson and Kumar 2000a;Steele et al 2018) to brackish water environments(Collins et al 2015;Van Hengstum et al 2015;, and have been used previously as indicators of lake trophic stateDrljepan et al 2014;Prentice et al 2018), salinization of lake systems(Roe and Patterson 2014;…”