DINOTROPHY: Deuterium in Organic Biomarkers: A new tool to investigate the role of Marine Mixotrophy in the Global Carbon Cycle

DINOTROPHY：有机生物标志物中的氘：研究海洋混合营养在全球碳循环中的作用的新工具

• 批准号: BB/V00994X/1
• 负责人: Michael Kendall
• 金额: $ 97.47万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FV00994X%2F1
• 关键词: DINOTROPHY; Deuterium; Organic; Biomarkers; new

Marine microscopic organisms drifting in the oceans (plankton) produce 50% of the oxygen we breath. Their activity helps maintain the balance of oxygen and carbon dioxide in the atmosphere. Much of this production is undertaken by eukaryote (non-bacterial) microbes called protists. Science has traditionally separated these marine protists between those akin to microscopic plants (autotrophs), getting their energy directly from the sunlight, or akin to microscopic animals (heterotrophs), getting their energy by eating other microbes. Recently, however, scientists have come to appreciate that many marine protists combine both autotrophic and heterotrophic (feeding) activities in the same single cell (mixotrophy). Mixotrophy alters marine food web functioning and affects the capacity of the oceans to remove carbon dioxide (counter climate change) from the atmosphere by increasing marine photosynthesis. This revelation overturns a century of understand in marine science, but also presents a severe challenge; traditional methods are targeted at autotrophy or heterotrophy, in separate organisms and we lack methods to determine mixotrophic activity. This project will develop a new tool to tackle this critical challenge. The high interest met in developing this project has already created a wide interdisciplinary network across the United Kingdom, France and Switzerland.Our team have previously shown that hydrogen isotopic signature of compounds produced in plants and bacteria (for instance into lipids) is uniquely sensitive to the balance of heterotrophy and autotrophy. This project will extend this investigation for compounds produced by marine microorganisms using similar approaches. We will target a particularly important group of mixotrophic protist plankton, the dinoflagellates, by measuring the hydrogen isotopic composition of specific compounds produced by dinoflagellates. Specifically, we will investigate the hydrogen isotope fractionation mechanisms (at molecular level, i.e. "site-specific") during biosynthesis of organic compounds and seek to establish the hydrogen isotope signature of marine lipids biomarkers (also used as molecular fossils) as a novel tool to investigate the behaviours of dinoflagellates in modern and past oceans and the impact of mixotrophy on the global carbon cycle.The core of the project will also produce of a numerical biochemical model uniquely possible by combining microorganism cultures and cutting-edge chemical analyses (including Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy) that will identify in detail the chemical steps responsible for the isotopic signature. By doing so, the project is also fostering a new cross-disciplinary group uniquely skilled in chemistry, isotope biogeochemistry and marine ecology dedicated to extend our knowledge of the marine microorganisms and their role on the Earth System.

漂浮在海洋中的海洋微生物(浮游生物)产生了我们呼吸的50%的氧气。它们的活动有助于维持大气中氧气和二氧化碳的平衡。这种生产大部分是由真核生物(非细菌)微生物进行的，这种微生物被称为原生生物。传统上，科学将这些海洋原生动物区分为类似于微型植物(自养生物)的海洋原生动物，它们直接从阳光中获取能量，或者类似于微型动物(异养生物)，通过吃其他微生物来获取能量。然而，最近，科学家们逐渐认识到，许多海洋原生动物在同一个细胞(混合营养)中既有自养又有异养(觅食)活动。混合营养物改变了海洋食物网的功能，并通过增加海洋光合作用影响海洋从大气中消除二氧化碳(应对气候变化)的能力。这一发现颠覆了一个世纪以来对海洋科学的理解，但也提出了一个严峻的挑战；传统方法针对的是自养或异养，在独立的生物体中，我们缺乏确定混合营养活性的方法。该项目将开发一种新的工具来应对这一关键挑战。开发这个项目的高度兴趣已经在英国、法国和瑞士建立了一个广泛的跨学科网络。我们的团队以前已经证明，在植物和细菌中产生的化合物(例如转化为脂类)的氢同位素特征对异质营养和自养的平衡是唯一敏感的。该项目将使用类似的方法将这项研究扩大到海洋微生物产生的化合物。我们将针对一类特别重要的混合营养原生浮游生物，即甲藻，通过测量甲藻产生的特定化合物的氢同位素组成。具体地说，我们将研究有机化合物生物合成过程中氢同位素分馏机制(在分子水平上，即“特定部位”)，并寻求建立海洋类脂生物标志物(也被用作分子化石)的氢同位素特征，作为研究现代和过去海洋中甲藻的行为以及混合营养对全球碳循环的影响的新工具。该项目的核心还将通过结合微生物培养和尖端化学分析(包括质谱学和核磁共振光谱)来建立一个独特的数值生化模型，该模型将详细识别导致同位素特征的化学步骤。通过这样做，该项目还培养了一个在化学、同位素生物地质化学和海洋生态学方面具有独特专长的新的跨学科小组，致力于扩大我们对海洋微生物及其在地球系统中的作用的知识。

项目成果

Deuterium in marine organic biomarkers: toward a new tool for quantifying aquatic mixotrophy.

• DOI: 10.1111/nph.18023
• 发表时间: 2022-05
• 期刊: NEW PHYTOLOGIST
• 影响因子: 9.4
• 作者: Cormier, Marc-Andre;Berard, Jean-Baptiste;Bougaran, Gael;Trueman, Clive N.;Mayor, Daniel J.;Lampitt, Richard S.;Kruger, Nicholas J.;Flynn, Kevin J.;Rickaby, Rosalind E. M.
• 通讯作者: Rickaby, Rosalind E. M.

A high-temperature water vapor equilibration method to determine non-exchangeable hydrogen isotope ratios of sugar, starch and cellulose.

• DOI: 10.1111/pce.14193
• 发表时间: 2022-01
• 期刊: PLANT CELL AND ENVIRONMENT
• 影响因子: 7.3
• 作者: Schuler, Philipp;Cormier, Marc-Andre;Werner, Roland A.;Buchmann, Nina;Gessler, Arthur;Vitali, Valentina;Saurer, Matthias;Lehmann, Marco M.
• 通讯作者: Lehmann, Marco M.

Stable Isotopes in Tree Rings: Inferring Physiological, Climatic and Environmental Responses

年轮中的稳定同位素：推断生理、气候和环境反应

• DOI: 10.5194/egusphere-egu2020-3680
• 发表时间: 2020
• 作者: R. Siegwolf;R. Brooks;J. Roden;M. Saurer
• 通讯作者: M. Saurer