REMineralisation of organic carbon by marine bActerIoplanktoN (REMAIN) - reducing the known unknown

海洋浮游细菌对有机碳的再矿化（REMAIN）——减少已知的未知

• 批准号: NE/R000956/1
• 负责人: Carol Robinson
• 金额: $ 81.63万
• 依托单位: University of East Anglia
• 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%2FR000956%2F1
• 关键词: REMineralisation; organic; carbon; marine; bActerIoplanktoN

The balance between the uptake of CO2 during phytoplankton photosynthesis and the production of CO2 during bacterial, zooplankton and phytoplankton respiration influences how much carbon can be stored in the ocean and hence how much remains in the atmosphere to affect climate. Yet, despite its crucial role, our knowledge of the respiration of component plankton groups such as bacteria, is severely limited because we do not have a method which can differentiate the respiration of one group from that of the rest of the community. We resort to measuring the respiration of a subsample which contains only cells which have passed through a filter. Just as we take in oxygen when we breathe, plankton take in oxygen when they respire and so the standard way to measure respiration is as the decrease in oxygen in the water. Unfortunately the low rates of respiration mean that measurements of oxygen have to be made over many hours and the disruption of the plankton foodweb by the filtration can lead to major errors.The recent development of a much more sensitive method (reduction of the tetrazolium salt INT) which can produce results in minutes and does not involve disruption of the plankton foodweb, is a major step forward and has revealed previously unknown variability. Unexpectedly, the results also suggest that the proportion of respiration attributable to the bacterial size class is consistently low, even in communities where bacteria are the most numerous plankton. This has profound implications for our understanding of the amount of CO2 produced by different plankton groups, and poses two new questions - which size class contributes most to plankton respiration if not the bacterial size class, and what influences the variability in respiration if not the type of plankton present. Marine scientists including ourselves have excitedly started to use the new INT technique, but it has not been thoroughly tested for all plankton communities. In fact, recent data suggest that the method can sometimes underestimate respiration because not all plankton can take up INT and sometimes overestimate respiration because compounds not associated with respiration can affect the INT. Thus while this method could potentially enable a critical improvement in our understanding and thus prediction of CO2 cycling in the ocean, these new intriguing results cannot be confirmed until a comprehensive test of the method has been completed. This is what we will do.We have brought together an international team of experts to undertake an innovative combination of laboratory and field work, taking advantage of a unique sampling opportunity - the Atlantic Meridional Transect - which allows the study of five different plankton ecosystems in the Atlantic Ocean. We will first develop a novel fluorescent method of tracking the uptake of INT into a representative range of plankton to quantify how different cells take it up. Then we will measure the INT reduction of both seawater samples and laboratory cultures to which have been added chemical inhibitors of plankton respiration and increasing concentrations of naturally occurring organic compounds, to determine to what extent these organic compounds lead to an overestimate of respiration. These results will be used to improve and validate the INT method. Finally we will participate in the research cruise to determine plankton respiration in size classes of the plankton community alongside identification of the plankton in these size classes and the concentration of organic compounds. The main deliverable of the project - apportionment of plankton respiration to plankton size classes - is of benefit to marine scientists who aim to predict how a changing climate will affect plankton production of CO2, policy makers interested in how much carbon can be stored in the ocean, and potentially commercial companies interested in the development of the fluorescent probe for medical or water quality applications.

浮游植物光合作用期间二氧化碳的吸收与细菌，浮游动物和浮游植物呼吸过程中二氧化碳的产生之间的平衡会影响海洋中可以存储多少碳，因此在大气中保留了多少碳来影响气候。然而，尽管它具有至关重要的作用，但我们对诸如细菌等组件浮游生物组的呼吸的了解受到了严重限制，因为我们没有一种可以将一个群体与社区其他成员区分开的方法。我们求助于测量仅包含通过过滤器的细胞的子样本的呼吸。正如我们在呼吸时吸入氧气一样，浮游生物在呼吸时会吸收氧气，因此测量呼吸的标准方法是水中的氧气减少。不幸的是，呼吸的速度较低，意味着必须在多个小时内进行氧气的测量，并且过滤对plankton foodweb的破坏可能会导致重大错误。最近的发展方法更敏感的方法（tetrazolium salt int降低）可能会在几分钟内产生结果，并且不涉及浮游生物的变化。出乎意料的是，结果还表明，即使在细菌是最多的浮游生物的社区，归因于细菌大小类别的呼吸的比例始终很低。这对我们对不同浮游生物组产生的二氧化碳数量的理解具有深远的影响，并提出了两个新问题 - 尺寸类别（如果不是细菌尺寸类别），哪个尺寸类别对浮游生物的呼吸有最大的作用，以及影响呼吸的变异性（如果不是浮游生物的类型）。包括我们在内的海洋科学家已经兴奋地开始使用新的INT技术，但并未对所有浮游生物社区进行彻底的测试。实际上，最近的数据表明，该方法有时会低估呼吸，因为并非所有浮游生物都可以接受INT，有时高估了呼吸，因为与呼吸无关的化合物会影响INT。因此，尽管该方法可能有可能在我们的理解中取得重要的改善，从而预测了海洋中二氧化碳循环的预测，但是直到对该方法进行了全面测试，这些新的有趣结果才能得到确认。这就是我们将要做的。我们召集了一个国际专家团队，利用独特的抽样机会 - 大西洋子午线式进行了实验室和现场工作的创新组合 - 这允许研究大西洋中五个不同的浮游生物生态系统。我们将首先开发一种新型的荧光方法，用于跟踪INT对浮游生物的代表性范围的摄取，以量化不同的细胞如何对其进行采用。然后，我们将衡量添加了浮游生物呼吸的化学抑制剂的海水样品和实验室培养物的INT降低，并增加了天然存在的有机化合物的浓度，以确定这些有机化合物在多大程度上导致了呼吸的高估。这些结果将用于改进和验证INT方法。最后，我们将参加研究巡航，以确定浮游生物社区尺寸类别的浮游生气呼吸，同时在这些尺寸类别中识别浮游生物和有机化合物的浓度。该项目的主要交付 - 浮游生物呼吸对浮游生物尺寸类别的分配 - 对海洋科学家有益，他们旨在预测气候变化将如何影响CO2的浮游生物产生，对海洋中可以存储多少碳的政策制定者以及对医疗或水质质量应用程序的开发感兴趣的潜在商业公司感兴趣的碳。

项目成果

Microbial Respiration, the Engine of Ocean Deoxygenation

• DOI: 10.3389/fmars.2018.00533
• 发表时间: 2019-01
• 期刊: Frontiers in Marine Science
• 影响因子: 3.7
• 作者: C. Robinson

Editorial: Zooplankton and Nekton: Gatekeepers of the Biological Pump

• DOI: 10.3389/fmars.2020.00545
• 发表时间: 2020-07
• 作者: R. Kiko;D. Bianchi;C. Grenz;H. Hauss;M. Iversen;Sanjeev Kumar;Amy E. Maas;C. Robinson

The Tropical Atlantic Observing System

• DOI: 10.3389/fmars.2019.00206
• 发表时间: 2019-05-10
• 期刊: FRONTIERS IN MARINE SCIENCE
• 影响因子: 3.7
• 作者: Foltz, G. R.;Brandt, P.;Reul, N.
• 通讯作者: Reul, N.

Diel vertical migration of a Southern Ocean euphausiid, Euphausia triacantha, and its metabolic response to consequent short-term temperature changes

南大洋磷虾的昼夜垂直迁移及其对短期温度变化的代谢反应

• DOI: 10.3354/meps13618
• 发表时间: 2021
• 期刊: Marine Ecology Progress Series
• 影响因子: 2.5
• 作者: Liszka C

Correcting a major error in assessing organic carbon pollution in natural waters.

纠正评估天然水域有机碳污染的重大错误

• DOI: 10.1126/sciadv.abc7318
• 发表时间: 2021-04
• 期刊: Science advances
• 影响因子: 13.6
• 作者: Jiao N;Liu J;Edwards B;Lv Z;Cai R;Liu Y;Xiao X;Wang J;Jiao F;Wang R;Huang X;Guo B;Sun J;Zhang R;Zhang Y;Tang K;Zheng Q;Azam F;Batt J;Cai WJ;He C;Herndl GJ;Hill P;Hutchins D;LaRoche J;Lewis M;MacIntyre H;Polimene L;Robinson C;Shi Q;Suttle CA;Thomas H;Wallace D;Legendre L
• 通讯作者: Legendre L