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.

海洋在确定世界气候方面起着重要作用。在某种程度上，这是由于非常小的单细胞生物的产生和二氧化碳（CO2）的消耗，这被称为光合作用的picoplankton。密切相关属氯环球菌和共氯菌的海洋蓝细菌是光合作用皮科浮游生物的原始成分，并且是地球上两个最丰富的光养护物！通过将大气中的二氧化碳固定到生物量中，这些生物是这种关键温室气体的水槽。这种碳（C）隔离的过程称为生物C泵，是我们在抵抗气候变化的战斗中拥有的最大自然资本形式。尽管这些蓝细菌正在不断生长和分裂，但控制它们生长速率的最重要因素之一，因此通过光合作用固定的二氧化碳量是营养素的可用性。海洋地区的供应这些必需营养素有很大不同，例如磷（P），氮（N）和铁。在p含量低的海洋区域，例如北大西洋和地中海海picocyanobacteria修改了其细胞成分以保护P。他们通过重塑其脂质成分来做到这一点。膜脂质构成了所有细胞的结构基础，它是细胞与外部环境之间的障碍。磷脂是蓝细菌细胞膜的主要组成部分，但在P耗竭的条件下，这些含P的脂质被非含有非P的硫脂素代替。这种自然重塑过程的生理和生态后果尚不清楚。换句话说，我们不知道这种重塑如何影响二氧化碳的固定速率，或者这如何影响这些生物运输（获取）其他营养的能力，并且会影响这些生物的元素组成，以及它们释放有机物的速度。这很重要。这很重要。这不仅是海洋鸟杆菌对全球二氧化碳的关键作用，而且由于固定的限制而言，这是预期的固定量，这是对全球二氧化碳的扩展，这是对Absion的预期，这是对未来的进一步的进一步的进一步的进一步的进一步的进一步。 全球暖化。因此，因此，了解他们的主要产量是否会在气候变暖的情况下会下降，增加或保持不变以及导致这一点的机制最终对于预测海洋生态系统功能的未来变化至关重要微营养素，从而修改其元素组成。这不仅是针对准确的初级生产估计值的后果，而且对这些细胞作为放牧者的猎物的营养质量（因此，能量转移到较高的营养水平）以及相反，当细胞下沉时从水柱中取出的细胞的元素组成以及C，因此C，n和p导出。我们还将确定N的限制是否还会触发脂质重塑响应，如果是这样，则它的后果。获得的所有数据将用于完善当前的生态系统模型制剂，描述了养分限制对初级生产的影响。考虑到脂质重塑对初级生产的影响的新配方将被实施到欧洲区域海洋生态系统模型（ERSEM）中，从而提供了对海洋初级生产的模拟实质性改进的。因此，该提案将提供直接的估计，并提供机械基础，以理解脂质重塑在控制海洋初级生产中的作用。随后将在ERSEM中使用数据和概念来完善海洋光合作用和随后的碳循环的控制点，并最终增强其预测能力。

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