Is the microcosm approach using meiofauna community descriptors a suitable tool for ecotoxicological studies?

Abstract

The usual approaches used in ecological risk assessment have been based on individual and population level standard procedures. Although these have been important tools to assess adverse effects on ecosystems, they are generally simplified and therefore lack ecological realism. Microcosm studies using meiobenthic communities offer a good compromise between the complexity of the ecosystem and the often highly artificial settings of laboratory experiments. An experiment was designed to investigate the potential of the microcosm approach using meiofauna as a tool for ecotoxicological studies. The experiment tested the ecological effects of exposure to sewage-impacted pore water simultaneously at the community level using meiofauna microcosms and at the individual level using laboratory fecundity tests with the copepod Nitokra sp. Specifically, the experiment tested the toxicity of pore water from three sites according to a contamination gradient. Both approaches were efficient in detecting differences in toxicity between the less and more contaminated sites. However, only multivariate data from community analysis detected differences in the gradient of contamination. In addition to information about toxicity, the community level microcosm experiment gave indications about sensitive and tolerant species, indirect ecological effects, as well as raised hypothesis about contamination routes and bioavailability to be tested. Considering the importance of meiofauna for benthic ecosystems, the microcosm approach using natural meiobenthic communities might be a valuable addition as a higher tier approach in ecological risk assessment, providing highly relevant ecological information on the toxicity of contaminated sediments.

The response of cultured meiofaunal and benthic foraminiferal communities to lead exposure: Results from mesocosm experiments

“…In contrast to the general tolerance of Nematoda observed in field studies (Mirto et al 2004;Semprucci et al 2015), Ostracoda's abundances appeared to be directly and negatively affected by Pb concentrations in sediment. This trend is in agreement with the results of other microcosm experiments that documented significant decreases of nematodes in relation to increased trace element concentrations (Gyedu-Ababio and Baird 2006;Hedfi et al 2007;Boufahja et al 2011;Chaaban Santos et al 2018). Recent studies on Caenorhabditis elegans have highlighted the fact that this species avoids feeding locations containing even low concentrations of Pb, which could interfere with its ability to find food (Monteiro et al 2014).…”

Short-term microplastic effects on marine meiofauna abundance, diversity and community composition

“…They (micro) bioturbate sediments ( Cullen, 1973 ) and form trophic links between lower trophic levels and higher ones, thereby influencing the cycling of organic matter and impacting the physical, chemical, and biological properties of the sediment ( Schratzberger & Ingels, 2018 ). Furthermore, meiofauna exhibit a remarkable diversity of animals with distinct phylogenies, functional characteristics and environmental sensitivities ( Giere, 2009 ; Pusceddu et al, 2007 ; Santos et al, 2018 ; Schratzberger & Ingels, 2018 ). In addition, due to characteristics such as a limited mobility and hence escape capacity and a short life cycle, they serve as a very useful tool for comprehending environmental impacts ( Giere, 2009 ; Schratzberger & Ingels, 2018 ).…”