Thorium Exposure Drives Fatty Acid and Metal Transfer from Biofilms to the Grazer Lymnaea sp.

Abstract

Aquatic ecotoxicological risks associated with tetravalent metallic elements such as thorium (Th) are still poorly understood. Periphytic biofilm represents an important food source in aquatic environments; thus, such risks could severely affect nutrient and energy cycling in these ecosystems. The present study investigated the potential for Th to change the fatty acid composition of biofilm communities. Bioaccumulation of Th and fatty acids were measured after 4 wk to 2 exposure conditions: a control (C0) and Th exposure (C10). Some major fatty acids such as C16:1n-7 and docosahexaenoic acid C22:6n-3 differed significantly between control and C10 conditions. To determine if Th can be trophically transferred and to investigate the impacts of nutritional quality changes on primary consumers, common pond snails (Lymnaea sp.) were fed for 4 wk with control and Th-exposed biofilm. Thorium appeared to be trophically transferable to the grazers, although we cannot exclude that part of the Th accumulated by the snails may have been taken from the water through release from the biofilms. The composition of major fatty acids observed in the grazers was also significantly affected, notably by a decrease of total polyunsaturated fatty acids. These results indicate that very low Th concentrations can decrease the nutritional quality of organisms at the base of the food chain.

Meta-metabolomic Responses of River Biofilms to Cobalt Exposure and Use of Dose-response Model Trends as an Indicator of Effects

“…[1][2][3] Effects of metals on biofilms have been shown at all levels of the biological organization, from subcellular 4,5 and cellular [6][7][8][9] levels to communities. 4,5,10 Among these effects, modification of metabolite contents are linked with contaminant concentration and exposure to stressors. 11 Metabolites are small molecular-weight molecules produced during metabolic processes.…”

New sensitive tools to characterize meta-metabolome response to short- and long-term cobalt exposure in dynamic river biofilm communities

“…Biofilms are also well-known to accumulate metals as a function of their respective ambient concentration and speciation (Meylan et al, 2003; Lavoie et al, 2012a; Laderriere et al, 2020). Metals can then induce numerous effects at all levels of biological organization, from subcellular (Barranguet et al, 2003; Bonet et al, 2013), cellular (Morin et al, 2008b; Duong et al, 2010; Lavoie et al, 2012b; Morin et al, 2017) through to community (Barranguet et al, 2003; Bonet et al, 2013; Doose et al, 2021).…”