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

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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.