Quantifying a marine ecosystem's response to a catastrophic oil spill

量化海洋生态系统对灾难性漏油的反应

• 批准号: NE/R016569/1
• 负责人: Boyd McKew
• 金额: $ 6.68万
• 依托单位: University of Essex
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FR016569%2F1
• 关键词: Quantifying; marine; ecosystem; response; catastrophic

Over 1.3 million tonnes of oil enters the sea each year from sources including oil rigs and tanker spills. Europe is particularly vulnerable to oil spills, as over half of the 20 biggest oil-shipping disasters have occurred there, including three in the UK. Recently on the 10th September the Agia Zoni oil tanker sank in the Saronic Gulf (near Athens, Greece) releasing over 2500 tonnes of fuel oil and marine gas into the marine environment. Such oil spills have severe impacts on the local marine life, tourism and fishing industry, as oil contains many different toxic hydrocarbons that can cause mass mortalities of birds, mammals, fish and shellfish. Fortunately there are some types of bacteria that can degrade hydrocarbons to naturally clean up the marine environment. Usually these specialist bacteria grow to very large numbers after an oil spill. However, it takes many different species of bacteria working together to degrade the hundreds of different types of hydrocarbons that are present in oil, and we still know very little about how these microbial consortia develop over time during an oil spill and subsequent clean-up operations. Oil spills can also have an impact on important microbially driven processes, such as the cycling of nitrogen. In marine environments, microorganisms convert nitrogen to different chemical forms (e.g. from ammonia to nitrite and then nitrate in a process known as nitrification), which can then be removed from the ecosystem as dinitrogen gas by denitrification. Too much nitrogen in the form of ammonia or nitrate could cause severe pollution problems, resulting in increased growth of algae, potentially triggering harmful and toxic algal blooms. Microorganisms involved in the N-cycle therefore perform vital ecosystem services, but presently we have very little understanding of how the nitrogen cycle is affected by large oil spills. In this study we will investigate some of these important research areas. Firstly, we will monitor the effects of the oil spill and subsequent clean-up operation over a 10-month period. We will determine which microorganisms (Bacteria, Archaea, Fungi and microalgae) are affected by the oil in either a positive way (e.g. increase in abundance of oil-degrading microbes) or negative way (e.g. direct toxicity of oil or being out-competed by oil-degrading microbes). This will be achieved by extracting DNA from oil-contaminated sediments and water followed by sequencing and quantifying taxonomic marker genes. At the same timepoints, we will measure changes in hydrocarbon composition and concentration. This will allow us to determine changes in the specialist hydrocarbon-degrading microbial communities in relation to hydrocarbon availability, and improve our understanding of the indigenous microbial community to remove the oil.We will also perform a focused analysis on N-cycling microorganisms (both nitrifying and denitrifying organisms) to determine how their abundances are affected in response to the oil spill. This will determine whether they may be any overall negative effects on the important ecosystem service that they perform.Finally our research will quantify the effect of the oil spill on the wider marine food web by recording effects on marine animals, including invertebrates such as shellfish, as well as fish and marine mammals, to establish which species are affected by oil spills and how well their populations recover from the spill over time.Since opportunities to study large oil spills in situ are rare, it is important for us to understand the effects of an oil spill in natural settings to enable the design of better oil remediation and management strategies for future spills and limit the damage they cause to coastal environments and marine life.

每年有超过130万吨石油从石油钻井平台和油轮泄漏等来源进入海洋。欧洲特别容易受到石油泄漏的影响，因为20起最大的石油运输灾难中有一半以上发生在欧洲，其中3起发生在英国。最近，9月10日，Agia Zoni油轮在萨罗尼湾(希腊雅典附近)沉没，向海洋环境中排放了2500多吨燃料油和海洋天然气。这类石油泄漏对当地海洋生物、旅游业和渔业造成严重影响，因为石油含有许多不同的有毒碳氢化合物，可能导致鸟类、哺乳动物、鱼类和贝类的大规模死亡。幸运的是，有一些类型的细菌可以降解碳氢化合物，从而自然地净化海洋环境。通常情况下，这些特殊细菌在石油泄漏后会生长到非常多的数量。然而，需要许多不同种类的细菌共同作用才能降解石油中存在的数百种不同类型的碳氢化合物，我们仍然对这些微生物联合体在漏油和随后的清理行动中如何随着时间的推移而发展知之甚少。石油泄漏还可能对重要的微生物驱动过程产生影响，例如氮气的循环。在海洋环境中，微生物将氮转化为不同的化学形式(例如从氨转化为亚硝酸盐，然后在称为硝化的过程中转化为硝酸盐)，然后通过反硝化作用将其作为氮气从生态系统中移除。过多的氨或硝酸盐氮可能会造成严重的污染问题，导致藻类生长加速，有可能引发有害和有毒的藻类水华。因此，参与N循环的微生物执行重要的生态系统服务，但目前我们对大规模石油泄漏如何影响N循环知之甚少。在这项研究中，我们将调查其中一些重要的研究领域。首先，我们将在10个月内监测漏油事件和随后的清理行动的影响。我们将确定哪些微生物(细菌、古生菌、真菌和微藻)受到石油的积极影响(例如，石油降解菌丰度的增加)或消极影响(例如，石油的直接毒性或被石油降解菌超越)。这将通过从受石油污染的沉积物和水中提取DNA，然后对分类标记基因进行测序和量化来实现。同时，我们将测量碳氢化合物组成和浓度的变化。这将使我们能够确定与碳氢化合物可用性相关的专业碳氢化合物降解菌群落的变化，并提高我们对本地微生物群落的了解，以去除石油。我们还将对N循环微生物(包括硝化菌和反硝化菌)进行重点分析，以确定它们的丰度如何受到漏油事件的影响。这将决定它们是否会对它们所执行的重要生态系统服务产生任何总体负面影响。最后，我们的研究将通过记录对海洋动物(包括贝类等无脊椎动物以及鱼类和海洋哺乳动物)的影响来量化石油泄漏对更广泛的海洋食物网的影响，以确定哪些物种受到石油泄漏的影响，以及随着时间的推移，它们的种群从泄漏中恢复得如何。由于现场研究大型石油泄漏的机会很少，我们必须了解石油泄漏在自然环境中的影响，以便能够为未来的石油泄漏设计更好的石油补救和管理战略，并限制它们对沿海环境和海洋生物造成的破坏。

项目成果

Marine Oil Snow, a Microbial Perspective

• DOI: 10.3389/fmars.2021.619484
• 发表时间: 2021-01
• 作者: Benjamin H Gregson;B. McKew;R. Holland;T. Nedwed;R. Prince;T. McGenity