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农工大学科珀斯克里斯蒂(TAMU-CC)购买净化和捕集同位素比质谱仪(PT-IRMS)，这将使关键的有机(例如氨基酸)和无机(例如硝酸盐)材料的前沿化合物特定同位素分析(CSIA)在一个位置实现。虽然大量组织和颗粒样品的氮(N)和碳稳定同位素分析已被广泛应用于考古学、天体生物化学、生态学、法医人类学、海洋学和古科学等多个研究领域，但单一化合物的同位素特征将揭示营养转移过程中和不同生理条件下食物网同位素基线和生化过程的更关键信息。总体而言，此次收购将扩大TAMU-CC的基础研究基础设施，并使TAMU-CC的不同用户群体能够进行协作和变革性的研究，以解决对社会至关重要的紧迫问题。此次收购将为TAMU-CC作为一所拉美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，特别是来自代表性较低群体(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物质(氨、硝酸盐和亚硝酸盐)转化而来的低水平(纳米分子)一氧化二氮(N2O)。该仪器将增强TAMU-CC的分析能力，并允许研究人员调查1)食物网对气候变化和人类活动引起的上升流变化(加利福尼亚州海湾)、水文循环变化(德克萨斯州沿海)和环境应激源干扰(墨西哥湾低氧)的响应；2)不同生理条件下浮游植物(生物碳泵和气候系统中的关键角色)的氮营养同化和氨基酸代谢；3)德克萨斯州海岸湿地和经历人类N负荷增加的河口的温室气体N2O的产生，这将为政策制定者提供关于德克萨斯州N缓解的关键信息；(4)珊瑚礁内氮营养交换机制对海洋酸化的响应。专用的PT-IRMS将进一步允许研究人员开发位置特定的同位素分析方法，用于可能包含未改变的N同位素基线信息的多氮氨基酸中的侧链-N。还将开发使用氨基酸CSIA的先进法医鉴定方法，以帮助识别德克萨斯州南部已故的越境者。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.