Sensitivity to Copper and Development of Culturing and Toxicity Test Procedures for the Antarctic Terrestrial Nematode Plectus murrayi

Abstract

Environmental quality guideline values and remediation targets, specific to Antarctic ecosystems, are required for the risk assessment and remediation of contaminated sites in Antarctica. Ecotoxicological testing with Antarctic soil organisms is fundamental in determining reliable contaminant effect threshold concentrations. The present study describes the development of optimal culturing techniques and aqueous toxicity test procedures for an endemic Antarctic soil nematode, Plectus murrayi, which lives within interstitial waters between soil particles. Toxicity tests were of extended duration to account for the species' physiology and life-history characteristics. Plectus murrayi was sensitive to aqueous copper with a 50% effective concentration for egg-hatching success of 139 µg/L. Hatched juveniles that were first exposed to copper as eggs appeared to be less sensitive than those first exposed at the hatched J2 stage, indicating a potential protective effect of the egg. Sensitivity of juveniles to copper increased with exposure duration, with 50% lethal concentrations of 478 and 117 µg/L at 21 and 28 d, respectively. The present study describes new methods for the application of an environmentally relevant test species to the risk assessment of contaminants in Antarctic soil and provides the first estimates of sensitivity to a toxicant for an Antarctic terrestrial microinvertebrate. Environ Toxicol Chem 2020;39:482-491. © 2019 SETAC

High Sensitivity of the Antarctic Rotifer Adineta editae to Metals and Ecological Relevance in Contaminated Site Risk Assessments

“…Bdelloid rotifers are an important component of these communities, being both the most abundant and the most biodiverse microinvertebrates found in limnoterrestrial ecosystems (Smykla et al, 2018; Velasco‐Castrillón, Page, et al, 2014; Wada et al, 2022). The present study provides evidence that bdelloid rotifers may represent a sensitive component of Antarctic terrestrial communities to metal contaminants (Brown et al, 2020; Dang et al, 2021; Koppel, Bishop, et al, 2021; McCarthy et al, 2022; Tomova et al, 2014). While the sensitivity estimates for A. editae from the present study add significantly to our understanding of the response of Antarctic terrestrial biota to metals, further work is required on a wider range of species for inclusion in risk assessments at contaminated sites and for the development of Antarctic site‐specific environmental guidelines and remediation targets.…”

“…The only other assessment of metal sensitivity to Antarctic terrestrial invertebrates is for the Antarctic nematode Plectus murrayi . This species was found to have a 21‐day EC50 for copper for egg hatching success of 139 (37–241) and a 21‐day LC50 for J2‐stage juveniles of 478 (358–598) µg Cu/L (Brown et al, 2020).…”

“…Potential invertebrate toxicity test species are limited to microinvertebrates such as nematodes, rotifers, tardigrades, springtails, and mites because macroinvertebrates are not found in Antarctic soils (Holdgate & Smith, 1967). Few Antarctic terrestrial invertebrate species have been used in toxicity testing, and to date there are only two published studies reporting sensitivity estimates to metals, both reporting the toxicity of copper: for the nematode Plectus murrayi (Brown et al, 2020) and the bdelloid rotifer Philodina sp. (McCarthy et al, 2022).…”

Signal Decoding for Glutamate Modulating Egg Laying Oppositely in Caenorhabditis elegans under Varied Environmental Conditions

“…The long-term exposure of excessive Cu decreases successful hatching and suppresses the development of eggs in pulmonate snail, Physa acuta ( Gao et al., 2017 ), and reduces C. elegans brood size and lead to internal hatching of offspring inside their mothers (bagging) ( Calafato et al., 2008 ). High level of Cu deteriorates hatching success and hatched juvenile survival in antarctic terrestrial nematode Plectus murrayi ( Brown et al., 2020 ). Here, we find that short-term Cu exposure augments egg laying in C. elegans .…”

Population growth of two limno-terrestrial Antarctic microinvertebrates in different aqueous soil media

“…A number of studies on the culturing of endemic Antarctic microinvertebrates have been published, including on nematodes (Adhikari et al 2010 ; De Tomasel et al 2013 ; Brown et al 2020 ), rotifers (Dougherty 1964a ; Dartnall 1992 ), tardigrades (Dougherty 1964b ; Altiero et al 2015 ) and springtails (McGaughran et al 2010 ). However, with the exception of artificial pore water utilised by Brown et al ( 2020 ), none of these studies have trialled analogues of the interstitial water in soil.…”