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

该合同支持在德克萨斯a&m大学科珀斯克里斯蒂（TAMU-CC）购买一个扫扫和捕集同位素比质谱仪（PT-IRMS），这将使关键有机（如氨基酸）和无机（如硝酸盐）材料的尖端化合物特异性同位素分析（CSIA）成为可能。尽管大量组织和颗粒样品的氮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、海洋学和古科学等众多研究领域，但单一化合物的同位素特征将揭示营养转移和不同生理条件下食物网同位素基线和生化过程的更重要信息。总的来说，这次收购将扩大TAMU-CC的基础研究基础设施，并使TAMU-CC的不同用户群体之间的协作和变革性研究能够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，通过为研究生和本科生，特别是那些来自代表性不足的群体（例如，McNair和LSAMP学者），平等获得尖端仪器和直接转移到STEM职业的实践经验，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，能够测量由氨基酸和无机含氮营养物质（铵、硝酸盐和亚硝酸盐）转化的低水平（纳米摩尔）氧化亚氮（N2O）。该仪器将提高TAMU-CC的分析能力，并允许研究人员调查1)食物网结构对上升流变化的响应（加利福尼亚湾），水文循环变化（德克萨斯州沿海），以及气候变化和人类活动引起的环境压力（墨西哥湾缺氧）的干扰；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)人为氮负荷升高的德克萨斯州沿海湿地和河口温室气体N2O的产生，这将为决策者提供德克萨斯州氮减排的关键信息；4)响应海洋酸化的珊瑚全息生物体内氮养分交换机制。专用PT-IRMS将进一步允许研究人员开发针对多氮氨基酸侧链N的位置特异性同位素分析方法，这些方法可能包含未改变的N同位素基线信息。还将开发利用氨基酸CSIA的先进法医鉴定方法，以帮助识别德克萨斯州南部的已故过境者。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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.