ANAMMARKS: ANaerobic AMmonium oxidiation bioMARKers in paleoenvironmentS

ANAMMARKS：古环境中的厌氧铵氧化生物标志物

• 批准号: NE/N011112/1
• 负责人: David Jones
• 金额: $ 72.01万
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FN011112%2F1
• 关键词: ANAMMARKS; ANaerobic; AMmonium; oxidiation; bioMARKers

In modern marine environment, 30-50% of nitrogen lost from the ocean is due to anaerobic ammonium oxidation (anammox). This bacterial process removes an important nutrient, nitrogen, from the marine phytoplankton system. Thus, anammox has a direct consequence on global marine primary production, the uptake of carbon dioxide, and the carbon cycle. Anammox bacteria performing this process are only active in low-oxygen to anoxic settings, included oxygen minimum zones (OMZs) in the water column. OMZs are expanding in our current changing climate and it is important to understand how this expansion will affect anammox activity and in turn the carbon cycle. Reconstructing paleoclimate in analogs for modern and future climate allows us to study how future changes will affect elements like the anammox processes. There are several instances in Earth's climate history when expanding OMZ has led to full-scale oceanic anoxia. Anammox bacteria are members of a deep-branching phylum, and the process has been hypothesised to have played an important role in creating and maintaining oceanic anoxia during crucial periods of Earth's history (e.g. Jurassic and Cretaceous Oceanic Anoxic Events (OAEs)). Determining how anammox was involved in these past scenarios will help better predict what likely outcomes we can expect in our future.Organic geochemistry uses molecular fossils, called biomarkers, to study the impact microbial processes have had on the environment. Currently, tracing anammox bacteria using biomarkers is done using ladderane lipids. However, the applicability of a biomarker has temporal limitations. For example, the inability to withstand degradative processes, which occur during and after deposition, restricts how far back in time these biomarkers can be applied. Although ladderane lipids are excellent biomarkers for modern environments, they are highly labile and not well suited for tracing past anammox activity. Thus, in order to clarify the role anammox has played during these past extreme climate events, lipids must first be identified that can be used as biomarkers in more mature sediments.Two distinct lipid classes have shown potential as biomarkers for past anammox, and will be assessed in this project. These lipids will be evaluated and will be implemented to trace anammox in past oceanic settings. The first class (bacteriohopanepolyols, specifically BHT isomer) seem suitable for sediments deposited within the last 50 Ma, and that have not been exposed to thermal stresses after burial. For example, we will apply these biomarkers to a 2 Myr sediment record underlying the Peru OMZ to explore the hypothesis that anammox influences the expansion of OMZs by contributing to nitrogen removal during increased OMZ. The second class (unusual cyclic and branched long-chain alkanes) extends the time window of detection into thermally mature sediments. These biomarkers will be investigated in OAE events to determine how anammox influenced a shift towards nitrogen-fixation being the dominate pathway of nutrient uptake during OAEs. Additionally, these alkanes will be economically benefit project partners in the petroleum industry, where biomarkers for anoxia would indirectly indicate preservation potential of organic matter and petroleum. We will create a simplified method for anammox detection that we will disseminate to other geochemistry laboratories for their studies of the anammox process. Combined, these findings and those specifically from our system studies will help understand past nitrogen cycling by using our established biomarkers to trace past anammox activity. Finally, the results of our studies of paleo-anammox will be incorporated into the biogeochemical model GENIE. This will improve our understanding of the role anammox played in past nitrogen cycling. Subsequently, model results will help to better predict the implications of anammox on future nitrogen and carbon cycling under our changing climate.

在现代海洋环境中，海洋中 30-50% 的氮损失是由于厌氧氨氧化 (anammox) 造成的。这种细菌过程从海洋浮游植物系统中去除了重要的营养物质氮。因此，厌氧氨氧化对全球海洋初级生产、二氧化碳的吸收和碳循环有直接影响。执行此过程的厌氧氨氧化细菌仅在低氧至缺氧环境中活跃，包括水柱中的最低氧区 (OMZ)。在当前不断变化的气候中，OMZ 正在扩张，了解这种扩张将如何影响厌氧氨氧化活动并进而影响碳循环非常重要。通过对现代和未来气候的模拟重建古气候，我们可以研究未来的变化将如何影响厌氧氨氧化过程等元素。在地球气候历史上，有好几次 OMZ 扩大导致全面海洋缺氧的例子。厌氧氨氧化细菌是深分支门的成员，并且该过程被认为在地球历史的关键时期（例如侏罗纪和白垩纪海洋缺氧事件（OAE））的产生和维持海洋缺氧方面发挥了重要作用。确定厌氧氨氧化如何参与这些过去的情况将有助于更好地预测我们未来可能出现的结果。有机地球化学使用分子化石（称为生物标记）来研究微生物过程对环境的影响。目前，使用生物标记物追踪厌氧氨氧化细菌是使用梯烷脂质完成的。然而，生物标志物的适用性有时间限制。例如，无法承受沉积过程中和沉积后发生的降解过程，限制了这些生物标记物的应用时间。尽管梯烷脂质是现代环境中极好的生物标志物，但它们高度不稳定，不太适合追踪过去的厌氧氨氧化活动。因此，为了阐明厌氧氨氧化在过去这些极端气候事件中所发挥的作用，必须首先鉴定出可用作更成熟沉积物中生物标志物的脂质。两种不同的脂质类别已显示出作为过去厌氧氨氧化生物标志物的潜力，并将被本项目中进行评估。这些脂质将被评估并用于追踪过去海洋环境中的厌氧氨氧化。第一类（细菌藿烷多元醇，特别是 BHT 异构体）似乎适用于过去 50 Ma 内沉积的沉积物，并且在埋藏后尚未暴露于热应力。例如，我们将这些生物标志物应用于秘鲁 OMZ 下方的 2 Myr 沉积物记录，以探索厌氧氨氧化通过在 OMZ 增加期间促进氮去除来影响 OMZ 扩张的假设。第二类（不寻常的环状和支链长链烷烃）将检测时间窗口扩展到热成熟沉积物。这些生物标志物将在 OAE 事件中进行研究，以确定厌氧氨氧化如何影响固氮的转变，固氮是 OAE 期间养分吸收的主要途径。此外，这些烷烃将成为石油行业的经济利益项目合作伙伴，其中缺氧的生物标志物将间接表明有机物和石油的保存潜力。我们将创建一种简化的厌氧氨氧化检测方法，并将其传播给其他地球化学实验室，以供他们研究厌氧氨氧化过程。结合起来，这些发现和我们系统研究的结果将通过使用我们已建立的生物标记物追踪过去的厌氧氨氧化活动来帮助了解过去的氮循环。最后，我们对古厌氧氨氧化的研究结果将被纳入生物地球化学模型GENIE中。这将提高我们对厌氧氨氧化在过去氮循环中所发挥的作用的理解。随后，模型结果将有助于更好地预测在我们不断变化的气候下厌氧氨氧化对未来氮和碳循环的影响。

项目成果

Analysis of non-derivatized bacteriohopanepolyols using UHPLC-HRMS reveals great structural diversity in environmental lipid assemblages

使用 UHPLC-HRMS 对非衍生化细菌藿烷多元醇的分析揭示了环境脂质组合物的巨大结构多样性

• DOI: 10.1016/j.orggeochem.2021.104285
• 发表时间: 2021
• 期刊: Organic Geochemistry
• 影响因子: 3
• 作者: Hopmans E

Unravelling the sources of carbon emissions at the onset of Oceanic Anoxic Event (OAE) 1a

• DOI: 10.1016/j.epsl.2019.115947
• 发表时间: 2020-01-15
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Adloff, Markus;Greene, Sarah E.;Monteiro, Fanny M.
• 通讯作者: Monteiro, Fanny M.

The Distribution of Structurally Diverse Adenosyl Bacterio-Hopanepolyols in Soils: Insight into Envrionmental Adaptations

结构多样的腺苷细菌藿烷多元醇在土壤中的分布：洞察环境适应

• DOI: 10.3997/2214-4609.202134197
• 发表时间: 2021
• 作者: Rush D

Dark carbon fixation in the Arabian Sea oxygen minimum zone contributes to sedimentary organic carbon (SOM)

阿拉伯海最低氧区的暗碳固定有助于沉积有机碳（SOM）

• DOI: 10.1029/2019gb006282
• 发表时间: 2019
• 期刊: Global Biogeochemical Cycles
• 影响因子: 5.2
• 作者: Lengger S

Fundamentally different global marine nitrogen cycling in response to severe ocean deoxygenation

• DOI: 10.1073/pnas.1905553116
• 发表时间: 2019-11
• 期刊: Proceedings of the National Academy of Sciences
• 作者: B. Naafs;F. Monteiro;A. Pearson;M. B. Higgins;R. Pancost;A. Ridgwell;A. Ridgwell