Elucidating the consequences of picocyanobacterial lipid remodelling for global marine primary production estimates

阐明微微蓝藻脂质重塑对全球海洋初级生产力估算的影响

• 批准号: NE/V000462/1
• 负责人: Jeremy Blackford
• 金额: $ 22.24万
• 依托单位: Plymouth Marine Laboratory
• 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=NE%2FV000462%2F1
• 关键词: Elucidating; consequences; picocyanobacterial; lipid; remodelling

The oceans play a major role in determining world climate. In part, this is due to the production of oxygen and the consumption of carbon dioxide (CO2) by very small, single celled organisms, which are referred to as the photosynthetic picoplankton. Marine cyanobacteria of the closely-related genera Prochlorococcus and Synechococcus are the prokaryotic components of the photosynthetic picoplankton and are the two most abundant phototrophs on Earth! By fixing CO2 from the atmosphere into biomass these organisms act as a sink for this key greenhouse gas. This process of carbon (C) sequestration, known as the biological C pump, is the greatest form of natural capital we possess in the fight against climate change. Whilst these cyanobacteria are continually growing and dividing, one of the most important factors controlling the rate at which they grow, and hence the amount of carbon dioxide that is fixed through photosynthesis, is the availability of nutrients. Oceanic regions vary considerably in their supply of these essential nutrients e.g. phosphorus (P), nitrogen (N) and iron. In oceanic regions where the levels of P are low e.g. the North Atlantic Ocean and Mediterranean Sea picocyanobacteria modify their cellular constituents to conserve P. They do this by remodelling their lipid composition. Membrane lipids form the structural basis of all cells, acting as a barrier between the cell and the external environment. Phospholipids are a major component of cyanobacterial cell membranes but under conditions of P depletion these P-containing lipids are replaced with non-P containing sulfolipids. The physiological and ecological consequences of this natural remodelling process are unknown. In other words we do not know how this remodelling affects rates of CO2 fixation or how this affects the ability of these organisms to transport (acquire) other nutrients and in turn affects the elemental composition of these organisms and the rate at which they release organic C. This is important because not only are marine cyanobacteria critical contributors to global CO2 fixation but their abundance is expected to increase in future years due to expansion of ocean gyres as a result of global warming. Thus, understanding whether their primary production will decline, increase or remain unchanged in the face of climate warming and the mechanisms causing this are ultimately critical to forecasting future changes in the functioning of marine ecosystems.Hence, in this proposal we will determine how lipid remodelling during P deplete growth under both current and elevated CO2 levels, affects the ability of marine cyanobacteria to fix CO2, acquire key macro- and micro-nutrients thereby modifying their elemental composition. This has consequences not only for accurate primary production estimates but also for the nutritional quality of these cells as prey for grazers (and hence for energy transfer to higher trophic levels) and conversely the elemental composition of cells removed from the water column when cells sink - and thus C, N and P export. We will also determine whether limitation for N also triggers a lipid remodelling response, and if so, its consequences. All of the data obtained will be used to refine current ecosystem model formulations describing the effect of nutrient limitation on primary production. The new formulation that takes into account the effect of lipid remodelling on primary production, will be implemented into the European Regional Seas Ecosystem Model (ERSEM) providing a substantially improved simulation of oceanic primary production.Overall, the proposal will therefore provide direct estimates, and a mechanistic basis, for understanding the role of lipid remodelling in controlling marine primary production. Data and concepts will subsequently be used in ERSEM to refine control points for marine photosynthesis and subsequent carbon cycling and ultimately enhance their predictive capability.

海洋在决定世界气候方面发挥着重要作用。这部分是由于非常小的单细胞生物产生氧气和消耗二氧化碳（CO2），这些生物被称为光合微型浮游生物。海洋蓝细菌的密切相关的属原绿球藻和聚球藻是原核组成部分的光合微微浮游生物，是两个最丰富的光养生物在地球上！通过将大气中的CO2固定到生物质中，这些生物体充当了这种关键温室气体的汇。这种碳（C）封存的过程，被称为生物碳泵，是我们在应对气候变化方面所拥有的最大形式的自然资本。虽然这些蓝藻不断生长和分裂，但控制它们生长速度的最重要因素之一，以及通过光合作用固定的二氧化碳量，是营养物质的可用性。海洋区域在提供这些基本营养素如磷（P）、氮（N）和铁方面差异很大。在磷含量低的海洋区域，例如北大西洋和地中海，微蓝细菌通过改变其脂质组成来改变其细胞成分以保存磷。膜脂形成所有细胞的结构基础，作为细胞和外部环境之间的屏障。磷脂是蓝藻细胞膜的主要成分，但在磷耗尽的条件下，这些含磷的脂质被替换为非含磷的硫脂。这种自然重塑过程的生理和生态后果是未知的。换句话说，我们不知道这种重塑如何影响CO2固定的速率，或者这如何影响这些生物体运输（获得）其他营养物质的能力，进而影响这些生物体的元素组成和它们释放有机碳的速率。这一点很重要，因为海洋蓝细菌不仅是全球二氧化碳固定的关键贡献者，而且由于全球变暖导致的海洋环流的扩大，它们的丰度预计将在未来几年增加。因此，了解它们的初级生产是否会下降，增加或保持不变，面对气候变暖和机制，导致这最终是至关重要的预测未来的变化，在海洋生态系统的功能。因此，在这个建议中，我们将确定如何在当前和升高的CO2水平下，在P耗尽生长脂质重塑，影响海洋蓝藻的能力，以固定CO2，获得关键的宏量和微量营养素，从而改变其元素组成。这不仅对准确的初级生产力估计有影响，而且对这些细胞作为食草动物猎物的营养质量也有影响（因此对能量转移到更高的营养水平），相反，当细胞下沉时，从水柱中去除的细胞的元素组成也有影响-因此C，N和P输出。我们还将确定限制N是否也会引发脂质重塑反应，如果是，其后果。所有获得的数据将用于完善目前的生态系统模型公式描述营养限制对初级生产的影响。新的配方，考虑到对初级生产的脂质重塑的影响，将实施到欧洲区域海洋生态系统模式（ERSEM）提供了一个大大改善的模拟海洋初级production.Overall的，因此，该提案将提供直接的估计，和一个机械的基础上，了解脂质重塑在控制海洋初级生产的作用。数据和概念随后将用于ERSEM，以完善海洋光合作用和随后的碳循环的控制点，并最终提高其预测能力。

项目成果

Complementary Approaches to Assess Phytoplankton Groups and Size Classes on a Long Transect in the Atlantic Ocean

评估大西洋长断面浮游植物群和大小等级的补充方法

• DOI: 10.3389/fmars.2021.682621
• 发表时间: 2022
• 期刊: Frontiers in Marine Science
• 影响因子: 3.7
• 作者: Brotas V

Coupling ecological concepts with an ocean-colour model: Phytoplankton size structure

• DOI: 10.1016/j.rse.2022.113415
• 发表时间: 2023-02
• 期刊: Remote Sensing of Environment
• 影响因子: 13.5
• 作者: Xuerong Sun;R. Brewin;S. Sathyendranath;G. Dall’Olmo;R. Airs;R. Barlow;A. Bracher;V. Brotas;M. Kheireddine;T. Lamont;E. Marañón;X. Morán;D. Raitsos;Fang Shen;G. Tilstone

Latitudinal variability and adaptation of phytoplankton in the Atlantic Ocean

大西洋浮游植物的纬度变化和适应

• DOI: 10.1016/j.jmarsys.2022.103844
• 发表时间: 2023
• 期刊: Journal of Marine Systems
• 影响因子: 2.8
• 作者: Barlow R

A compilation of global bio-optical in situ data for ocean colour satellite applications – version three

海洋颜色卫星应用的全球生物光学现场数据汇编 - 第三版

• DOI: 10.5194/essd-14-5737-2022
• 发表时间: 2022
• 期刊: Earth System Science Data
• 影响因子: 11.4
• 作者: Valente, André;Sathyendranath, Shubha;Brotas, Vanda;Groom, Steve;Grant, Michael;Jackson, Thomas;Chuprin, Andrei;Taberner, Malcolm;Airs, Ruth;Antoine, David
• 通讯作者: Antoine, David