title: Biochemical and physiological responses of Carcinus maenas to temperature and the fungicide azoxystrobin.
abstract: Research on the effects of thermal stress is currently pertinent as climate change is expected to cause more severe climate-driven events. Carcinus maenas, a recognised estuarine model organism, was selected to test temperature-dependence of azoxystrobin toxicity, a widely applied fungicide. Crabs' responses were assessed after a 10-d acclimation at different temperatures (5°C, 22°C, and 27°C) of which the last 72h were of exposure to an environmental concentration of azoxystrobin. SOD and GST activities, mitochondrial oxygen consumption rates and protein content, as well as the Coupling Index were determined. The hypothesis proposed that extreme temperatures (5°C and 27°C) and azoxystrobin would affect crabs' responses. Results showed statistically significant different effects of SOD and all oxygen rates measured promoted by temperature, and that neither 30.3μgL(-1) of azoxystrobin nor the combined effect were crab-responsive. Protein content at 5°C was statistically higher when compared with the control temperature (22°C). The Coupling Index revealed both a slight and a drastic decrease of this index promoted by 5°C and 27°C, respectively. Regarding azoxystrobin effects, at 22°C, this index only decreased slightly. However, at extreme temperatures it fell 47% at 5°C and slightly increased at 27°C. Results provided evidence that crabs' responses to cope with low temperatures were more effective than their responses to cope with high temperatures, which are expected in future climate projections. Moreover, crabs are capable of handling environmental concentrations of azoxystrobin. However, the Coupling Index showed that combined stress factors unbalance crabs' natural capability to handle a single stressor.
authors.affiliation: CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal. Electronic address: etrodrig@zoo.uc.pt.
authors.forename: Elsa Teresa
authors.initials: ET
authors.lastname: Rodrigues
authors.affiliation: IMAR - Instituto do Mar, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal. Electronic address: moreno@ci.uc.pt.
authors.forename: António
authors.initials: A
authors.lastname: Moreno
authors.affiliation: CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal. Electronic address: tfmendes@student.uc.pt.
authors.forename: Tito
authors.initials: T
authors.lastname: Mendes
authors.affiliation: CNC - Center for Neuroscience and Cell Biology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal. Electronic address: palmeira@zoo.uc.pt.
authors.forename: Carlos
authors.initials: C
authors.lastname: Palmeira
authors.affiliation: CFE - Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal. Electronic address: mpardal@zoo.uc.pt.
authors.forename: Miguel Ângelo
authors.initials: MÂ
authors.lastname: Pardal
mesh_terms: D000064:Acclimatization / Q000187:drug effects; D000818:Animals; D003386:Brachyura / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D057231:Climate Change; D054750:Ecotoxicology; D005659:Fungicides, Industrial / Q000633:toxicity*; D008689:Methacrylates / Q000633:toxicity*; D011743:Pyrimidines / Q000633:toxicity*; D012621:Seasons; D000073739:Strobilurins; D013696:Temperature
chemical_list: D005659:Fungicides, Industrial; D008689:Methacrylates; D011743:Pyrimidines; D000073739:Strobilurins; C087670:azoxystrobin
keywords: Azoxystrobin; Carcinus maenas; Enzymatic activity; Mitochondrial performance; Multi-stressors; Temperature