Acute and sub-chronic effects of sub-lethal cadmium exposure on energy metabolism in the freshwater shrimp, Paratya curvirostris.
Cadmium (Cd) is a toxic trace element enriched in waters through activities such as mining and agriculture. The freshwater shrimp Paratya curvirostris inhabits near-coastal, lowland streams potentially impacted by Cd, but nothing is known regarding its sensitivity to this metal. An acute (96h) median lethal concentration (LC50) of 405µgL-1was derived for P. curvirostris, placing it among the most tolerant of freshwater shrimp species. Acute (4 d; 0, 50 and 100µgL-1) and sub-chronic (10 d; 0, 25 and 50µgL-1) exposures then investigated effects of Cd on energy metabolism (respiration rate, excretion rate, O:N ratio). In contrast to effects in previously studied species, Cd induced an increased respiration rate, which when coupled with an unchanged excretion rate, resulted in an increased O:N ratio. These data were explained by an increased reliance on carbohydrate and/or lipid as a metabolic substrate stimulated by increased metabolic costs of toxicant exposure. Similar effects were seen across all time-points, although the lowest effective Cd concentration decreased with increased exposure time. Overall, results suggest that Cd is unlikely to be a significant environmental stressor to P. curvirostris, except in highly contaminated freshwaters, and/or where Cd co-occurs with hypoxia.
School of Biological Sciences, University of Canterbury, New Zealand.
Rathishri
R
Chandurvelan
School of Biological Sciences, University of Canterbury, New Zealand.
Islay D
ID
Marsden
Department of Chemistry, University of Canterbury, New Zealand.
Sally
S
Gaw
School of Biological Sciences, University of Canterbury, New Zealand; Athabasca River Basin Research Institute and Faculty of Science and Technology, Athabasca University, Alberta, Canada; Department of Biological Sciences, University of Alberta, Canada. Electronic address: cglover@athabascau.ca.
Chris N
CN
Glover
D000818:Animals; D002104:Cadmium / Q000633:toxicity*; D033364:Decapoda / Q000187:drug effects* / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects*; D004784:Environmental Monitoring; D005260:Female; D005618:Fresh Water / Q000737:chemistry*; D009520:New Zealand; D023382:Toxicity Tests, Acute; D059550:Toxicity Tests, Subchronic; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D014874:Water Pollutants, Chemical; D002104:Cadmium
Bioenergetics; Cadmium; Crustacean; Nitrogen excretion; Oxygen consumption; Toxicity