MRI: Acquisition of a Purge and Trap Isotope Ratio Mass Spectrometer for Compound/Position-Specific Applications in Biogeochemistry and Ecological Studies at TAMU Corpus Christi

该奖项支持在德克萨斯农工大学科珀斯克里斯蒂分校 (TAMU-CC) 购买一台吹扫捕集同位素比质谱仪 (PT-IRMS)，这将能够在一个地点对关键有机（例如氨基酸）和无机（例如硝酸盐）材料进行领先的化合物特异性同位素分析 (CSIA)。虽然对大块组织和颗粒样品进行氮 (N) 和碳稳定同位素分析已广泛应用于考古学、天体生物化学、生态学、法医人类学、海洋学和古科学等各种研究领域，但单一化合物的同位素特征将揭示有关营养转移期间和不同生理条件下食物网同位素基线和生化过程的更多关键信息。总体而言，此次收购将扩大 TAMU-CC 的基础研究基础设施，并促进 TAMU-CC 不同用户群体之间的协作和变革性研究，解决对社会重要的紧迫问题。此次收购将为 TAMU-CC 作为西班牙裔服务机构和少数族裔服务机构的教育目标做出根本性贡献，为研究生和本科生，特别是那些来自代表性不足群体（例如 McNair 和 LSAMP 学者）的学生，提供平等获得尖端仪器和可直接转移到 STEM 职业的实践经验的机会，这将促进地区和国家 STEM 劳动力的多样性和包容性。 TAMU-CC 将获得定制的 PT-IRMS，能够测量从氨基酸和无机含氮营养素（铵、硝酸盐和亚硝酸盐）转化而来的低水平（纳摩尔）一氧化二氮 (N2O)。该仪器将增强 TAMU-CC 的分析能力，并使研究人员能够研究 1) 食物网结构对气候变化和人类活动引起的上升流变化（加利福尼亚湾）、水文循环变化（德克萨斯州沿海）以及环境压力源干扰（墨西哥湾缺氧）的响应； 2) 不同生理条件下浮游植物（生物碳泵和气候系统的关键参与者）的氮养分同化和氨基酸代谢，3) 德克萨斯州沿海湿地和河口经历人为氮负荷升高时温室气体 N2O 的产生，这将为政策制定者提供有关德克萨斯州氮减排的关键信息； 4）珊瑚全生物体内响应海洋酸化的氮养分交换机制。专用的 PT-IRMS 将进一步允许研究人员开发多氮氨基酸中侧链 N 的位置特异性同位素分析方法，其中可能包含未改变的 N 同位素基线信息。还将开发使用 CSIA 氨基酸的先进法医鉴定方法，以帮助识别南德克萨斯州已故的过境者。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award supports the acquisition of a Purge and Trap Isotope Ratio Mass Spectrometer (PT-IRMS) at Texas A&M University Corpus Christi (TAMU-CC), which will enable leading-edge compound-specific isotope analysis (CSIA) of key organic (e.g., amino acids) and inorganic (e.g., nitrate) materials in one location. While nitrogen (N) and carbon stable isotope analysis of bulk tissue and particle samples have been broadly used in a remarkable variety of research fields such as archeology, astrobiochemistry, ecology, forensic anthropology, oceanography, and paleo-sciences, the isotopic signatures of single compounds will reveal more critical information on food web isotope baselines and biochemical processes during trophic transfer and under different physiological conditions. Broadly, this acquisition will expand TAMU-CC's basic research infrastructure and enable collaborative and transformative research among a diverse group of users at TAMU-CC that addresses pressing questions of importance to society. This acquisition will make a fundamental contribution to TAMU-CC’s education goals as a Hispanic Serving Institution and Minority Serving Institution, by providing graduate and undergraduate students, especially those from underrepresented groups (e.g., McNair and LSAMP scholars), equal access to cutting-edge instrumentation and hands-on experience directly transferrable to STEM careers, which will promote diversity and inclusion in both regional and national STEM workforces. TAMU-CC will acquire a customized PT-IRMS with the ability to measure low levels (nanomoles) of nitrous oxide (N2O) converted from amino acids and inorganic nitrogenous nutrients (ammonium, nitrate, and nitrite). This instrument will enhance analytical capabilities at TAMU-CC and allow researchers to investigate 1) food web structural response to variation in upwelling (Gulf of California), alterations in hydrological cycles (coastal Texas), and disturbance by environmental stressors (hypoxia in the Gulf of Mexico) caused by climate change and human activities; 2) nitrogenous nutrient assimilation and amino acid metabolism in phytoplankton (key players in the biological carbon pump and climate systems) under different physiological conditions, 3) greenhouse gas N2O production in Texas coastal wetlands and estuaries experiencing elevated anthropogenic N loading, which will provide key information to policy-makers regarding N mitigation in Texas; and 4) nitrogenous nutrient exchange mechanisms within coral holobionts in response to ocean acidification. A dedicated PT-IRMS will further allow researchers to develop position-specific isotope analytical methods for the sidechain-N in polynitrogenous amino acids which may contain unaltered N isotope baseline information. Advanced forensic identification methods using CSIA of amino acids will also be developed to help identify deceased border crossers in South Texas.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.