Division of Aquaculture and Seafood Upgrading. Portuguese Institute for the Sea and Atmosphere, I.P. (IPMA), Rua Alfredo Magalhães Ramalho, 6, 1495-006 Lisboa, Portugal; Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal; MARE - Marine and Environmental Sciences Centre, Laboratório Marítimo da Guia, Faculdade de Ciências da Universidade de Lisboa, Av. Nossa Senhora do Cabo, 939, 2750-374 Cascais, Portugal.
Division of Aquaculture and Seafood Upgrading. Portuguese Institute for the Sea and Atmosphere, I.P. (IPMA), Rua Alfredo Magalhães Ramalho, 6, 1495-006 Lisboa, Portugal.
Sci Total Environ. 2017 May 15;586:551-558. doi: 10.1016/j.scitotenv.2017.02.016. Epub 2017 Feb 16.
The ecotoxicological effects of methylmercury (MeHg) exposure have been intensively described in literature. Yet, it is still unclear how marine biota will respond to the presence of MeHg under climate change, namely ocean warming. The present study aimed to investigate, for the first time, fish condition [Fulton's K index (K), hepatosomatic index (HIS) and brain-to-body mass ratio (BB-ratio)] and several stress-related responses in an ecologically and commercially important fish species (Dicentrachus labrax) exposed for 28days to dietary MeHg (8.0mg kg-1 dw) and temperature increase (+4°C). Results showed significant impairments on fish condition, i.e. up to 34% decrease on K, >100% increase on HIS and 44% decrease on BB-ratio, compared to control conditions. Significant changes on tissue biochemical responses were observed in fish exposed to both stressors, acting alone or combined, evidencing the relevance of assessing possible interactions between different environmental stressors in ecotoxicological studies. For instance, muscle showed to be the least affected tissue, only revealing significant alterations in GST activity of MeHg-enriched fish. On the other hand, liver exhibited a significant induction of GST (>100%) and CAT (up to 74%) in MeHg-enriched fish, regardless of temperature exposure, as well as decreased SOD activity (19%) and increased HSP70/HSC70 content (87%) in fish exposed to warming alone. Brain showed to be affected by temperature (69% of GST inhibition and >100% of increased CAT activity), MeHg (>100% of increased CAT activity, 47% of SOD inhibition and 55% of AChE inhibition), as well as by the combination of both (GST, SOD and AChE inhibition, 17%, 48% and 53%, respectively). Hence, our data provides evidences that the toxicological aspects of MeHg ca be potentiated by warmer temperatures, thus, evidencing the need for further research combining contaminants exposure and climate change effects, to better forecast ecological impacts in the ocean of tomorrow.
甲基汞（MeHg）暴露的生态毒理学效应在文献中已有详细描述。然而，海洋生物在气候变化（即海洋变暖）下对 MeHg 的存在将如何做出反应仍不清楚。本研究首次旨在调查（即，鱼类状况[富尔顿的 K 指数（K）、肝体比（HIS）和脑体比（BB-比）]和几种与应激相关的反应），在暴露于饮食甲基汞（8.0mg kg-1 dw）和温度升高（+4°C）的 28 天后，在一种生态和商业上都很重要的鱼类（条纹鲈）中。结果表明，与对照条件相比，鱼类的状况有显著受损，K 下降高达 34%，HIS 增加超过 100%，BB-比下降 44%。单独或联合暴露于两种应激源的鱼类组织生化反应发生显著变化，这表明在生态毒理学研究中评估不同环境应激源之间可能相互作用的相关性非常重要。例如，肌肉是受影响最小的组织，仅在富含 MeHg 的鱼类中发现 GST 活性有显著改变。另一方面，肝脏在富含 MeHg 的鱼类中表现出 GST（增加超过 100%）和 CAT（高达 74%）的显著诱导，无论是否暴露于温度，以及 SOD 活性降低（19%）和 HSP70/HSC70 含量增加（87%），仅在单独暴露于升温的鱼类中。大脑受到温度（GST 抑制 69%，CAT 活性增加超过 100%）、MeHg（CAT 活性增加超过 100%，SOD 抑制 47%，AChE 抑制 55%）以及两者的组合（GST、SOD 和 AChE 抑制，分别为 17%、48%和 53%）的影响。因此，我们的数据提供了证据表明，MeHg 的毒理学方面可能会因变暖而加剧，从而表明需要进一步研究结合污染物暴露和气候变化影响，以更好地预测未来海洋的生态影响。
