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气候变化耦合海洋污染的生态毒理学研究进展
Research progress in ecotoxicology of climate change coupled with marine pollutions
【摘要】 工业化以来,海洋污染已成为全球性环境问题;CO2浓度持续增加下,气候变化也给海洋环境带来了显著改变.目前,大量的研究集中在气候变化或者环境污染各自单独对海洋生物及生态系统的影响,并已取得一些广泛认可的结论.然而,现实环境中,生物实际处在气候变化与海洋污染的双重胁迫下,生物与生态系统受到的影响极有可能更加复杂和严峻.因此,气候变化耦合海洋污染的生态毒理学研究越来越受到关注.本文在概述气候变化与海洋污染的基础上,总结了气候变化下海洋环境的改变,特别是海水升温、酸化、低氧等对典型海洋污染物如重金属和持久性有机污染物(persistent organic pollutants,POPs)等的生物毒性的影响,分析了气候变化与海洋污染的交互作用,提出当前研究所面临的问题并展望未来的研究前景,为准确评估全球气候变化下的海洋生态风险以及促进我国全球气候变化应对提供基础.
【Abstract】 Marine pollution has become a global problem since industrialization. Global climate change has also brought significant changes to the marine environment, especially with the continuously increasing atmospheric CO2 concentration. Lots of studies have solely focused on the influences of climate change or environmental pollutants on marine biota and ecosystem, and made some widely-accepted conclusions. However, in the real environment, marine ecosystem is likely suffering more complex impacts than that exposed to either marine pollution or climate change only. Thus research of climate change coupled with marine pollution is being more and more concerned by the government and scientists, and becomes a hotspot in the field of marine environmental science and global climate change. In the present research, effects of climate change(especially rising sea water temperature, acidification and hypoxia) on the biotoxicity of typical marine pollutants(e.g., heavy metals, POPs), as well as the interactions between climate change and marine pollution were summarized. On the one hand, ocean warming, acidification and hypoxia affect the resistance of marine organisms on pollutants, and further affect their sensitivity to pollutants; on the other hand, ocean warming, acidification and hypoxia affect the physical and chemical properties, environmental behaviors and bioavailability of marine pollutants directly, and thus change pollutants’ toxicity indirectly. Therefore, under the coupled stress of climate change and marine pollution, toxic effects of pollutants may not only be the simple superposition of the two alone, but also more complex synergies. For example, ocean warming changes the distribution of POPs between the water-gas phase significantly, which makes POPs migrate to higher latitudes through the grasshopper effect and increases the exposure risk of polar organisms to POPs. Warming increases the solubility of heavy metals in seawater, but also increases the precipitation of metal oxides and hydroxides(reducing the solubility of metal ions) due to the increased rate of chemical reactions. This paradox is a difficulty in the current quantitative study for effects of ocean warming on metal solubility. Ocean acidification promotes the releasing of Cu2+ in forms of carbonate compound, or makes Cd2+ and Hg2+ dissociate from their compounds in the sea water, while heavy metals in forms of free state are generally more toxic to marine organisms than those in forms of compounds, thus exacerbating the toxicity of heavy metals to marine organisms. Hypoxia promotes the reduction of arsenic from the pentavalent state to the trivalent state. The arsenic in the trivalent state binds to the thiol-containing protein in the marine organism and inactivates the acetylcholine(AChE) enzyme. According to the statistical report of literatures, studies related to climate change coupled with marine pollution had been rarely reported before 2003, and have been receiving more and more attentions since 2003. In terms of content, the studies mainly focus on combined effects of acidification-heavy metals(slightly more), acidification-nanomaterials as well as organic matters(less), hypoxia-heavy metals as well as organic matters(small amounts), and warming-heavy metals(small amounts) on marine organisms; focused on the effects of acidification on the transport of marine pollutants in food chains(small amounts); focused on the ecological risk of POPs and mercury in the polar region under the background of climate change(slightly more). These studies have shown that climate change does affect the environmental behavior and biological toxicity of marine pollutants directly or indirectly. Ocean plays an important role in maintaining the Earth’s system and climate regulation. From the perspective of how to protect the ocean scientifically and utilize marine resources reasonably under coupled stress of climate change and marine pollution, authors proposed that following fields should be considered seriously in future:(1) mechanisms underlying the interaction between climate change and marine pollution;(2) effects of coupled stresses between climate change and environmental pollution on ocean primary productivity and carbonate system;(3) problems related to coastal ecological risks.
【Key words】 climate change; marine pollution; coupled stress; heavy metal; persistent organic pollutants(POPs); biotoxicity;
- 【文献出处】 科学通报 ,Chinese Science Bulletin , 编辑部邮箱 ,2018年Z1期
- 【分类号】X171.5;X55
- 【被引频次】6
- 【下载频次】825