Microbial carbon cycling in marine environments: linking micro-scale processes to global carbon dynamics

海洋环境中的微生物碳循环：将微观过程与全球碳动态联系起来

• 批准号: RGPIN-2019-04228
• 负责人: Mahmoudi, Nagissa
• 金额: $ 1.82万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751015
• 关键词: Microbial; carbon; cycling; marine; environments

The ocean is home to complex and diverse microorganisms that shape the dynamics of these ecosystems in a myriad of ways. Through their metabolism and growth, marine microorganisms play a central role in the global carbon cycle and influence the size and magnitude of carbon that becomes sequestered in deep ocean waters and sediments. My research focuses on heterotrophic microorganisms which break down organic carbon and release carbon dioxide (CO2) as a byproduct of their metabolism, this is referred to as the remineralization of organic matter. Heterotrophic microorganisms are the primary producers of CO2 in the ocean and any substantial change in their metabolic activity has the potential to significantly alter how carbon is processed and stored in the ocean. The proposed research will use a variety of molecular and isotopic tools to gain new insights into the controls on heterotrophic microorganisms as well as the metabolic pathways and ecological interactions that underpin carbon cycling in the ocean. The core research questions are: 1) how does the metabolic potential of microorganisms influence organic matter remineralization? (2) do ecological interactions between microorganisms increase or decrease rates of organic matter remineralization? and (3) is cell density an important control on the production of enzymes that initiate the remineralization of organic matter? These questions will be examined through three testable hypotheses in studies conducted by two MSc students, two PhD students and four undergraduate students. Overall the results of this research will advance our understanding of the microbial mechanisms that regulate carbon fluxes in the ocean. Ultimately, this will allow us to develop a much needed molecular-level framework to improve our ability to predict how marine carbon cycling will change under a future warmer climate. Additionally, microorganisms play a direct role in remediating spilled oil in the ocean. Deciphering the fundamental mechanisms that regulate microbial activity will greatly improve our ability to develop oil spill response plans and remediation strategies. This research program will maintain and build Canada's profile in this critical field of research, especially as global climate change threatens the health of our oceans. I have played a leading role in establishing new research tools that aim to understand the interactions between microorganisms and organic carbon. My interdisciplinary background in the fields of isotope geochemistry, molecular biology and microbiology, make me uniquely qualified to lead the proposed research program.

海洋是复杂多样的微生物的家园，它们以无数方式塑造着这些生态系统的动态。海洋微生物通过其新陈代谢和生长，在全球碳循环中发挥核心作用，并影响到封存在深海沃茨和沉积物中的碳的大小和数量。我的研究重点是异养微生物，它分解有机碳并释放二氧化碳（CO2）作为其代谢的副产品，这被称为有机物的微生物化。异养微生物是海洋中二氧化碳的主要生产者，其代谢活动的任何实质性变化都有可能显著改变海洋中碳的加工和储存方式。拟议的研究将使用各种分子和同位素工具，以获得对异养微生物的控制以及支持海洋碳循环的代谢途径和生态相互作用的新见解。核心研究问题是：1）微生物的代谢潜力如何影响有机物的矿化？(2)微生物之间的生态相互作用是增加还是减少了有机物的矿化速率？以及（3）细胞密度是否是启动有机物再矿化的酶的产生的重要控制因素？这些问题将通过三个可检验的假设进行研究，由两个硕士生，两个博士生和四个本科生。总的来说，这项研究的结果将促进我们对调节海洋碳通量的微生物机制的理解。最终，这将使我们能够开发出一个急需的分子水平框架，以提高我们预测海洋碳循环在未来气候变暖下将如何变化的能力。此外，微生物在补救海洋中的溢油方面发挥着直接作用。破译调节微生物活动的基本机制将大大提高我们制定溢油应急计划和补救策略的能力。这一研究方案将保持和建立加拿大在这一关键研究领域的形象，特别是在全球气候变化威胁到我们海洋健康的情况下。 我在建立新的研究工具，旨在了解微生物和有机碳之间的相互作用发挥了主导作用。我在同位素地球化学，分子生物学和微生物学领域的跨学科背景，使我唯一有资格领导拟议的研究计划。