Biology Department & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
Chemistry Department & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal; CIIMAR, Interdisciplinary Centre of Marine and Environmental Research , Rua dos Bragas 289, 4050-123 Porto, Portugal.
Sci Total Environ. 2017 Dec 1;601-602:1129-1138. doi: 10.1016/j.scitotenv.2017.05.201. Epub 2017 Jun 9.
The interest in the consequences of climate change on the physiological and biochemical functioning of marine organisms is increasing, but the indirect and interactive effects resulting from warming on bioconcentration and responsiveness to pollutants are still poorly explored, particularly in terms of cellular responses. The present study investigated the impacts of Hg in Mytilus galloprovincialis under control (17°C) and warming (21°C) conditions, assessing mussels Hg bioconcentration capacity, metabolic and oxidative status after 14 and 28days of exposure. Results obtained showed greater impacts in mussels exposed for 28days in comparison to 14days of exposure. Furthermore, our findings revealed that the increase in temperature from 17 to 21°C reduced the bioconcentration of Hg by M. galloprovincialis, which may explain higher mortality rates at 17°C in comparison to 21°C. Lower Hg concentration at 21°C in mussels tissue may result from valves closure for longer periods, identified by reduced energy reserves consumption at higher temperature, which in turn might also contributed to higher oxidative stress in organisms exposed to this condition. The highest LPO levels observed in mussels exposed to higher temperatures alone indicate that warming conditions will greatly affect M. galloprovincialis. Furthermore, the present study showed that the impacts induced by the combination of Hg and warming were similar to the ones caused by increased temperature acting alone, mainly due to increased antioxidant defenses in organisms under combined effects of Hg and warming, suggesting that warming was the factor that mostly contributed to oxidative stress in mussels. Although higher mortality was observed in individuals exposed to 17°C and Hg compared to organisms exposed to Hg at 21°C, the oxidative stress induced at higher temperature may generate negative consequences on mussels reproductive and feeding capacity, growth and, consequently, on population maintenance and dynamics.
人们对气候变化对海洋生物生理和生化功能影响的兴趣日益增加，但对于变暖对污染物生物浓缩和响应的间接和交互影响，特别是在细胞反应方面，仍研究甚少。本研究调查了 Hg 在贻贝中的影响在对照（17°C）和升温（21°C）条件下，评估了贻贝对 Hg 的生物浓缩能力、代谢和氧化状态在暴露 14 和 28 天后的情况。结果表明，与暴露 14 天相比，暴露 28 天对贻贝的影响更大。此外，我们的研究结果表明，温度从 17°C 升高到 21°C 降低了贻贝对 Hg 的生物浓缩能力，这可能解释了与 21°C 相比，17°C 下更高的死亡率。在贻贝组织中，Hg 浓度较低可能是由于阀门长时间关闭，这是由于在较高温度下消耗的能量储备减少所致，这反过来也可能导致暴露于这种条件下的生物体产生更高的氧化应激。仅在高温下暴露的贻贝中观察到的最高 LPO 水平表明，升温条件将对贻贝产生重大影响。此外，本研究表明，Hg 和升温的联合作用所引起的影响与单独升温引起的影响相似，主要是由于在 Hg 和升温的联合作用下生物体的抗氧化防御能力增强，这表明升温是导致贻贝氧化应激的主要因素。尽管与暴露在 21°C 下的 Hg 的生物体相比，暴露在 17°C 和 Hg 下的个体死亡率更高，但在较高温度下诱导的氧化应激可能对贻贝的繁殖和摄食能力、生长以及随后的种群维持和动态产生负面影响。
