title: Influence of global change-related impacts on the mercury toxicity of freshwater algal communities.
abstract: The climatic-change related increase of temperatures, are expected to alter the distribution and survival of freshwater species, ecosystem functions, and also the effects of toxicants to aquatic biota. This study has thus assessed, as a first time, the modulating effect of climate-change drivers on the mercury (Hg) toxicity of freshwater algal photosynthesis. Natural benthic algal communities (periphyton) have been exposed to Hg under present and future temperature scenarios (rise of 5 °C). The modulating effect of other factors (also altered by global change), as the quality and amount of suspended and dissolved materials in the rivers, has been also assessed, exposing algae to Hg in natural river water or a synthetic medium. The EC50 values ranged from the 0.15-0.74 ppm for the most sensitive communities, to the 24-40 ppm for the most tolerant. The higher tolerance shown by communities exposed to higher Hg concentrations, as Jabarrella was in agreement with the Pollution Induced Community Tolerance concept. In other cases, the dominance of the invasive diatom Didymosphenia geminata explained the tolerance or sensitivity of the community to the Hg toxicity. Results shown that while increases in the suspended solids reduced Hg bioavailability, changes in the dissolved materials - such as organic carbon - may increase it and thus its toxic effects on biota. The impacts of the increase of temperatures on the toxicological behaviour of periphyton (combining both changes at species composition and physiological acclimation) would be certainly modulated by other effects at the land level (i.e., alterations in the amount and quality of dissolved and particulate substances arriving to the rivers).
authors.affiliation: Pyrenean Institute of Ecology, CSIC, Av. Montañana 1005, Zaragoza 50059, Spain; Research Institute for Environment and Sustainability of San Jorge University, Villanueva de Gállego, 50830, Zaragoza, Spain; FACOPS Foundation, Calle Pineta 17, 50410 Cuarte de Huerva, Zaragoza, Spain.
authors.forename: Jonatan
authors.initials: J
authors.lastname: Val
authors.affiliation: Pyrenean Institute of Ecology, CSIC, Av. Montañana 1005, Zaragoza 50059, Spain.
authors.forename: Selene
authors.initials: S
authors.lastname: Muñiz
authors.affiliation: Dept. of Ecology, University of Barcelona, Av. Diagonal 645, Barcelona 08026, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Gomà
authors.affiliation: Pyrenean Institute of Ecology, CSIC, Av. Montañana 1005, Zaragoza 50059, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Navarro
mesh_terms: D057231:Climate Change; D017377:Diatoms / Q000187:drug effects*; D017753:Ecosystem; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry*; D008628:Mercury / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Acclimatization; Climatic change; Didymosphenia geminata; Mercury; Microcosms; Periphyton