Collaborative Research: Key Microbial Processes in Oxygen Minimum Zones: From In Situ Community Rate Measurements to Single Cells

合作研究：最低氧气区的关键微生物过程：从原位群落速率测量到单细胞

• 批准号: 1924424
• 负责人: Gordon Taylor
• 金额: $ 51.5万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-10-01 至 2024-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1924424&HistoricalAwards=false
• 关键词: Collaborative; Research; Key; Microbial; Processes

Oxygen availability shapes the distributions and activities of marine organisms. Ongoing human activities and climate change are expected to lead to expansion and intensification of already large oxygen-stressed areas of the coastal and open ocean. Decreases in ocean oxygen have significant ecological consequences, including habitat loss for migratory and bottom-dwelling organisms, modification of the marine food web, and production of trace gases with pronounced feedbacks on climate, such as methane and nitrous oxide. Intense chemical cycling by microorganisms occurs in oxygen-depleted marine habitats. However, a full understanding of the consequences for marine ecosystems is hampered by limited knowledge of actual rates of key microbiological processes and dynamics of the microorganisms mediating them. This study combines novel methods and sampling techniques to understand how these processes are influenced by changes in oxygen concentration to inform predictions of important chemical exchanges within a changing ocean and its production of climate-active gases. This deeply collaborative project trains undergraduates (four of whom participate on the cruise), a graduate student and a postdoctoral fellow. Outreach takes place in middle and high schools and through social media. Data and samples from the cruise are integrated in coursework.Oxygen depletion alters cycling of major elements (especially carbon, nitrogen, and sulfur) as well as food web functionality. This project addresses major gaps in our knowledge of oxygen minimum zone (OMZ) processes by applying in situ approaches to more accurately measure rates of several key microbial processes (chemoautotrophy, denitrification, anammox, sulfate reduction and sulfide oxidation) central to marine biogeochemical cycling. This work studies the Eastern Tropical North Pacific OMZ, the largest open ocean oxygen-depleted system, to 1) determine the in situ rates of microbial processes involved in carbon, nitrogen, and sulfur cycling, 2) reveal the genomic blueprint of active single cells involved in these processes, and 3) obtain estimates of the relative contributions of the dominant chemoautotrophic and heterotrophic groups to the measured rates. This work include applies cutting-edge equipment for in situ sampling and incubations that minimize artifacts associated with traditional water sampling approaches, allowing more accurate estimates of rates of important biogeochemical processes. Additionally, rate measurements of relatively undisturbed bulk and fractionated water samples make it easier to distinguish the potential role of particle-associated microorganisms in these OMZ processes. Single cell sorting of microorganisms using a fluorescent dye indicative of cell activity together with metatranscriptomics informs on metabolic pathways used for key processes by active microbial community members, as well as the potential coupling of chemoautotrophy and nitrogen or/and sulfur cycling. By combining stable isotope probing, fluorescence in situ hybridization and single cell Raman microspectrometry the relative activity levels of different microbial phylotypes involved in chemoautotrophic and heterotrophic elemental cycling are assessed.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

氧的可用性塑造了海洋生物的分布和活动。预计正在进行的人类活动和气候变化将导致沿海和开阔海洋已经很大的氧气压力区域的扩张和加剧。海洋氧的减少具有重大的生态后果，包括迁移和底层生物体的栖息地丧失，对海洋食品网的修饰以及具有明显反馈的气候反馈（例如甲烷和氧化二氮）的痕量气体的产生。微生物的强烈化学循环发生在耗氧的海洋栖息地中。但是，对海洋生态系统的后果的全面了解受到对关键微生物过程的实际速率和介导的微生物动态的实际知识的有限了解。这项研究结合了新的方法和抽样技术，以了解这些过程如何受氧气浓度变化的影响，以告知对海洋不断变化的重要化学交换的预测及其气候活性气体的产生。这个深入的协作项目训练本科生（其中四名参加巡航），一名研究生和博士后研究员。外展活动在中学和通过社交媒体进行。巡航中的数据和样本都集成在课程中。氧耗竭改变了主要元素（尤其是碳，氮和硫）以及食物网络功能的循环。该项目通过将原位方法应用于更准确的测量几个关键的微生物过程（化学二硝化，硝酸化，厌氧酸盐，硫酸盐还原和硫化物氧化）中心，从而解决了我们对氧最小区域（OMZ）过程中的主要差距。这项工作研究了东部热带北太平洋OMZ，最大的开放海氧耗尽的系统，至1）确定与碳，氮和硫磺循环相关的微生物过程的原位速率，2）揭示了与这些过程有关的活性单细胞的基因组蓝ePrint，并获得了这些过程的估计，以及3）获得了相对贡献的估计，并获得了相对贡献的估计值测量率。这项工作包括应用尖端设备进行原位采样和孵化，以最大程度地减少与传统水样方法相关的伪影，从而更准确地估计重要的生物地球化学过程的速率。另外，对相对不受干扰的体积和分离水样品的速率测量使得更容易区分与粒子相关的微生物在这些OMZ过程中的潜在作用。使用荧光染料的微生物分类，指示细胞活性以及元文字组合学的单细胞分类，并了解主动微生物群落成员用于关键过程的代谢途径，以及化学养分营养和氮或氮或/和/和/和硫磺自行车的潜在偶联。通过结合稳定的同位素探测，原位杂交和单细胞拉曼微光谱法的相对活性水平来评估NSF的法定任务和综述的依据，评估了该奖励的依据，评估了这一奖励的依据，评估了这一奖项的相对型元素奖。