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大马蹄螺(Trochus niloticus)对海水酸化和热应激/ 磺胺甲恶唑复合暴露的生理响应
张天宇
Subtype硕士
2020-05-30
Degree Grantor中国科学院烟台海岸带研究所
Place of Conferral中国科学院烟台海岸带研究所
Degree Name工程硕士
Keyword大马蹄螺,海洋酸化,海洋暖化,磺胺甲恶唑,综合生物标志物
Abstract近年来,化石能源燃烧、森林砍伐等工农业活动向大气中排放了大量的CO2,由此产生的温室效应导致了表层海水温度的持续升高;同时,海洋吸收了约1/3人类活动排放的CO2,也导致了海水pH值的持续降低,这种现象被称为海洋酸化,其被认为是继“温室效应”之后由CO2过量排放而引起的又一全球性环境问题。此外,人类活动还向海洋中排放了大量的污染物,主要包括营养盐类、重金属、石油及石油类产品、抗生素、持久类有机污染物和塑料制品等,导致了近海环境的严重破坏,从而对海洋生物的生存和繁衍以及海洋生态系统的结构和功能构成了严重威胁。 我国南海海域拥有丰富的珊瑚礁资源,具有重要的生态服务价值及经济价值;目前,我国的南海珊瑚礁生态系统正遭受着气候变化和人类活动双重因素的威胁,西沙群岛珊瑚礁生态系统中的活珊瑚比例已不足10%。大马蹄螺(Trochus niloticus)作为南海珊瑚礁生态系统中重要的植食性腹足类动物,其对大型底栖藻类的啃食作用可有效控制珊瑚礁生态系统中藻类的生物量,从而保证珊瑚在与藻类的生态位竞争中处于优势地位。本研究旨在评估南海珊瑚礁生态系统中关键种大马蹄螺在未来气候情景与环境条件下的生理状态,以期为其种群动态评估以及珊瑚礁生态系统的环境风险评价提供基础数据。研究主要包括以下两部分: (1)大马蹄螺对海水酸化和热应激暴露的生理响应:人类活动向大气中排放的大量CO2对海洋环境造成了严重的影响,主要表现为海水酸化和温度升高,二者往往同时发生且对生物的影响存在协同或拮抗作用。本研究以南海珊瑚礁生态系统中的关键种大马蹄螺为实验对象,采用传统生理生态学技术手段,探讨了海水酸化和热应激两种环境胁迫条件单独及复合暴露28天对大马蹄螺免疫防御、氧化应激、神经毒性和能量代谢等相关生物标志物或生理过程的影响。研究结果表明,海水酸化和热应激单独暴露均会诱导大马蹄螺免疫系统和抗氧化系统产生应激反应,此类生理响应导致大马蹄螺消耗更多的能量,从而改变其能量分配策略。根据综合生物标志物分析结果,本研究条件下的海水酸化(pH 7.6)和热应激(温度30 ℃)复合暴露对大马蹄螺造成的胁迫压力高于其他处理组,机体表现出免疫能力降低、氧化应激、神经毒性和代谢紊乱等现象,提示长期暴露可能会导致大马蹄螺种群的衰退。 (2)大马蹄螺对海水酸化和磺胺甲恶唑暴露的生理响应:除由气候变化引起的扰动以外,海洋生物还面临着环境污染等多种压力因素的胁迫;多重胁迫因素间的交互作用通常呈现非线性形态,从而导致其对关键生态类群的影响复杂且难以预测。磺胺甲恶唑是南海海域的典型抗生素污染种类,其在环境中的降解过程受海水pH等环境因素的影响;目前,海水酸化和磺胺甲恶唑复合暴露对海洋关键生态类群生理过程的影响机制尚不明确。本研究以大马蹄螺为实验对象,采用传统生理生态学技术手段,探讨了海水酸化和磺胺甲恶唑单独及复合暴露28天对大马蹄螺免疫防御、氧化应激和能量代谢等相关生物标志物或生理过程的影响。研究结果表明,海水酸化单独暴露(pH 7.6)会诱导大马蹄螺产生氧化应激和免疫应答反应,同时伴随着体内能量分配策略的改变;磺胺甲恶唑暴露(1000 ng/L)能够导致大马蹄螺体内出现氧化应激现象,并伴随着呼吸率的升高,表明大马蹄螺能够通过自身生理状态的调整以适应磺胺甲恶唑的胁迫作用。然而,在海水酸化和磺胺甲恶唑复合暴露下,大马蹄螺机体的免疫机能受损,表现为血淋巴细胞吞噬功能受到抑制;同时,抗氧化酶系统不能及时清除体内产生的自由基,导致机体出现氧化损伤现象;此外,酸化和磺胺甲恶唑复合暴露条件下大马蹄螺体内脂质和糖原的消耗量增加,且电子传递链活性显著升高,表明能量分配模式在该条件下受到显著影响。上述结果提示,在海水酸化和磺胺甲恶唑复合暴露条件下,大马蹄螺的环境适应能力受损;若长期保持此状态,大马蹄螺的生存和繁殖将会受到潜在影响。
Other AbstractIn recent years, industrial and agricultural activities such as the burning of fossil energy and deforestation have emitted a large amount of CO2 into the atmosphere. After the ocean absorbs approximately 1/3 of CO2, the pH value of the seawater continues to decrease, and the temperature of the seawater continues to increase due to the aggravation of the greenhouse effect. In addition, human activities also emit a large amount of pollutants into the ocean, including antibiotics, persistent organic pollutants, heavy metals, petroleum and plastic products, causing serious damage to the marine environment. Consequently, survival and reproduction of marine organisms and structure and function of ecosystem are under grave threat. Coral reef ecosystems have the most complex community structure on the planet and underpin a range of ecosystem goods and services for human societies. At present, coral reefs in the South China Sea are threaten by climate change and human activities, it is estimated that the coverage of coral in the area is less than 10%. Trochus niloticus is an important herbivorous gastropod in the coral reef ecosystem of the South China Sea. It can effectively control the algae biomass as grazers and ensure the domination of coral in coral reef ecosystem. This study aims to assess the physiological status of the key species T. niloticus in the coral reef ecosystem of the South China Sea, and to provide basic data for its population dynamics assessment and coral reef ecosystem environmental risk assessment under future climate and environmental conditions. The research mainly includes the following parts: (1) Physiological responses of Trochus niloticus to seawater acidification combined with thermal stress exposure: The large amount of CO2 released into the atmosphere by human activities has caused serious impacts on the marine environment, mainly including ocean acidification and warming, which often occur simultaneously and have synergistic or antagonistic effects on marine organisms. In order to figure out the physiological responses of the key species in the coral reef ecosystem of the South China Sea, T. niloticus was exposed to ocean acidification and/or thermal stress for 28 days. The results show that both seawater acidification and thermal stress alone can induce immune responses and oxidative stress of T. niloticus, which could consume more energy reserves and result in the adjustment of energy allocation in T. niloticus. According to the results of integrated biomarker response, co-exposure of ocean acidification and thermal stress in this experiment caused the most severe pressure on T. niloticus, leading to reduced immunity, impaired oxidative balance, neurotoxicity and disorder of energy metabolism. (2) Physiological responses of Trochus niloticus to seawater acidification combined with sulfamethoxazole exposure: In addition to the disturbances caused by climate change, marine organisms were also facing numerous stressors such as environmental pollution. The results are complicated and hard to predict when marine organisms facing multiple environmental stress. Sulfamethoxazole is a typical antibiotic found in the South China Sea, and its degradation process in the environment is affected by environmental factors such as seawater pH. In this study, the immune defense, oxidative stress and energy metabolism of T. niloticus were investigated after 28 days of exposure to ocean acidification and/or sulfamethoxazole. It was found seawater acidification exposure induced immune and anti-oxidant responses, as well as change of energy distribution in T. niloticus. Sulfamethoxazole exposure could stimulate antioxidant reactions and oxygen consumption in T. niloticus, indicating that topshells could acclimate to the stress of sulfamethoxazole through adjustment of its physiological state. However, under the co-exposure condition, a series of negative impacts were observed in T. niloticus, including impaired immune system which manifest as reduction of phagocytosis; excessive reactive oxygen species leading to oxidative stress; reduction of lipid and glycogen content and increased activity of electron transport system in digestive glands indicative of impaired cellular energy allocation. It was suggested that T. niloticus cannot cope with the stress caused by co-exposure, and these physiological alterations have potential effects on the survival and reproduction of T. niloticus in the long run.
MOST Discipline Catalogue工学::生物工程
Language中文
Document Type学位论文
Identifierhttp://ir.yic.ac.cn/handle/133337/24233
Collection中科院烟台海岸带研究所知识产出_学位论文
Recommended Citation
GB/T 7714
张天宇. 大马蹄螺(Trochus niloticus)对海水酸化和热应激/ 磺胺甲恶唑复合暴露的生理响应[D]. 中国科学院烟台海岸带研究所. 中国科学院烟台海岸带研究所,2020.
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