Blewett Tamzin A, Simon Robyn A, Turko Andy J, Wright Patricia A
Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario, N2L 3C5, Canada.
Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada.
Aquat Toxicol. 2017 Aug;189:25-30. doi: 10.1016/j.aquatox.2017.05.007. Epub 2017 May 23.
Elevated levels of metals have been reported in mangrove ecosystems worldwide. Mangrove fishes also routinely experience severe environmental stressors, such as hypoxia. In the amphibious fish Kryptolebias marmoratus (mangrove rivulus), a key behavioural response to avoid aquatic stress is to leave water (emersion). We hypothesized that copper (Cu) exposure would increase the sensitivity of this behavioural hypoxia avoidance response due to histopathological effects of Cu on gill structure and function. K. marmoratus were exposed to either control (no added Cu) or Cu (300μg/L) for 96h. Following this period, fish were exposed to an acute hypoxic challenge (decline in dissolved oxygen to ∼0% over 15min), and the emersion response was recorded. Gills were examined for histological changes. Fish exposed to Cu emersed at a higher dissolved oxygen level (7.5±0.6%), relative to the control treatment group (5.8±0.4%). Histological analysis showed that the gill surface area increased and the interlamellar cell mass (ILCM) was reduced following Cu exposure, contrary to our prediction. Overall, these data indicate that Cu induces hypoxia-like changes to gill morphology and increases the sensitivity of the hypoxia emersion response.
据报道，全球红树林生态系统中的金属含量有所升高。红树林鱼类也经常面临严重的环境压力源，如缺氧。在两栖鱼类红树鳉（Kryptolebias marmoratus）中，避免水生应激的一个关键行为反应是离开水体（上岸）。我们假设，由于铜对鳃结构和功能的组织病理学影响，接触铜（Cu）会增加这种行为性缺氧回避反应的敏感性。将红树鳉暴露于对照（不添加铜）或铜（300μg/L）环境中96小时。在此之后，让鱼接受急性缺氧挑战（在15分钟内将溶解氧降至约0%），并记录上岸反应。检查鳃的组织学变化。与对照处理组（5.8±0.4%）相比，接触铜的鱼在更高的溶解氧水平（7.5±0.6%）时上岸。组织学分析表明，与我们的预测相反，接触铜后鳃表面积增加，板间细胞团（ILCM）减少。总体而言，这些数据表明，铜会导致鳃形态发生类似缺氧的变化，并增加缺氧上岸反应的敏感性。
