Collaborative Research: Phylogenetic and Physiological Characterization of Amino Acid Nitrogen Isotopes in Phytoplankton

合作研究：浮游植物氨基酸氮同位素的系统发育和生理学特征

• 批准号: 2242041
• 负责人: Lin Zhang
• 金额: $ 44.51万
• 依托单位: Texas A&M University Corpus Christi
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2242041&HistoricalAwards=false
• 关键词: Collaborative; Research; Phylogenetic; Physiological; Characterization

Phytoplankton are microscopic plants that live in the ocean and act as the base of the marine food web. These microorganisms use inorganic nitrogen (N) from the water to make a variety of amino acids. Some of the amino acids keep the initial chemical signature (i.e., N isotope value) of their N source. Other amino acids are involved in metabolic processes that change the initial chemical signature (N isotope value). These distinct N isotope signatures are passed along to organisms that consume phytoplankton and throughout the food web. Thus, the N isotope values of individual amino acids can be used to obtain the isotope value of N sources supporting food webs and to estimate the trophic position of organisms in biota, particles, coral skeletons, and sediments. But, this requires a clear understanding of the N isotope patterns of amino acids produced by phytoplankton. This project will examine whether different phytoplankton species produce amino acids with distinct N isotope patterns when using the same N source. The project will also study whether the N isotope patterns produced by the same species of phytoplankton change under different growth and environmental conditions. Information from this study will improve the ability to use N isotope values in amino acids in ecological and biogeochemical studies. This collaborative project combines novel research with broader impacts focused on engaging the public and promoting diversity and inclusion at various levels. Three graduate students and one postdoc will participate in the research. Research opportunities will be provided to undergraduate students, especially those with backgrounds. Students will be recruited through the McNair and Louis Stokes Alliances for Minority Participation program at Texas A&M Univ. at Corpus Christi, a Hispanic Serving and Minority Serving Institution. To share results broadly, the investigators and students will give talks about marine science to local K-12 students in Corpus Christi TX. The New Bedford High School (in MA) summer marine intern program will be engaged in this project. Public lectures will be given on the topic of algal blooms and a children’s article will be written on the topic of isotopes. Outcomes of this project will also be incorporated into presentations to the Chesapeake Bay Program, Maryland Harmful Algal Bloom Task Force, and the Scientific and Technical Advisory Committee of the Maryland Coastal Bays. The use of N isotope values of different amino acids (δ15N-AA) to retrieve the N source isotope signature of food webs and estimate trophic positions depends on information about the δ15N-AA produced by phytoplankton at the base of the food web which is still poorly understood. This study seeks to explore fundamental scientific questions to better understand δ15N-AA produced by phytoplankton. 1) Under the same nitrogenous nutrient and growth conditions, do δ15N-AA patterns vary between major phytoplankton groups? Are the unique δ15N-AA patterns in diatoms related to unique aspects of their N metabolism? 2) Do changes in phytoplankton physiology resulting from nitrogenous nutrient availability, N form utilized (ammonium, nitrate, and mixed), and/or other growth conditions independently produce significant changes in δ15N-AA? Phytoplankton samples will be collected from controlled culture (e.g., chemostat) experiments and from field studies in the Gulf of Mexico and Chesapeake Bay, especially during near-monospecific bloom events. By taking the advantage of newly developed analytical approaches, new knowledge of compound and intramolecular δ15N of poly-N AA such as arginine, asparagine, glutamine, and histidine in phytoplankton will be generated for the first time. This ground-truthing work will advance the understanding of δ15N-AA pattern produced by key phytoplankton species critical to the biological pump and harmful algal blooms under environmentally relevant physiological conditions. The expected outcomes from this work will enable new applications and more sophisticated trophic position analyses, studies of the efficiency of the ocean’s biological pump, and paleo-oceanographic reconstructions using amino acids preserved in natural archives.This project is funded by the Biological and Chemical Oceanography Programs.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.

浮游植物是生活在海洋中的微小植物，是海洋食物网的基础。这些微生物利用水中的无机氮(N)制造各种氨基酸。有些氨基酸保留了其氮源的初始化学特征(即N同位素值)。其他氨基酸参与新陈代谢过程，改变最初的化学特征(N同位素值)。这些不同的N同位素信号被传递给消耗浮游植物的生物和整个食物网。因此，单个氨基酸的N同位素值可以用来获得支持食物网的氮源的同位素值，并可以估计生物群、颗粒、珊瑚骨骼和沉积物中生物的营养位置。但是，这需要清楚地了解浮游植物产生的氨基酸的N同位素模式。这个项目将研究不同的浮游植物物种在使用相同的氮源时是否产生具有不同N同位素模式的氨基酸。该项目还将研究同一物种浮游植物产生的氮同位素模式是否会在不同的生长和环境条件下发生变化。这项研究的信息将提高在生态和生物地球化学研究中使用氨基酸中N同位素的能力。这一合作项目将新颖的研究与更广泛的影响结合起来，侧重于让公众参与并在不同层面促进多样性和包容性。三名研究生和一名博士后将参与这项研究。将为本科生提供研究机会，特别是那些有背景的人。学生将通过麦克奈尔和路易斯·斯托克斯少数族裔参与联盟计划在德克萨斯农工大学招募。在科珀斯克里斯蒂，一个西班牙裔服务和少数族裔服务机构。为了广泛分享结果，研究人员和学生将在科珀斯克里斯蒂德克萨斯州科珀斯克里斯蒂向当地K-12学生讲授海洋科学。新贝德福德高中(马萨诸塞州)夏季海洋实习生计划将参与这个项目。将举行关于藻类水华主题的公开讲座，并将撰写一篇关于同位素主题的儿童文章。该项目的成果还将被纳入切萨皮克湾项目、马里兰州有害藻华工作组和马里兰州沿海海湾科学和技术咨询委员会的报告中。利用不同氨基酸的N同位素值(δ15N-AA)来恢复食物网的N源同位素特征并估计营养位置依赖于有关浮游植物在食物网底部产生的δ15N-AA的信息，这一信息仍然知之甚少。本研究旨在探索基础科学问题，以更好地了解浮游植物产生的δ15N-AA。1)在相同的氮素营养和生长条件下，主要浮游植物类群之间的δ15N-AA模式是否有所不同？硅藻中独特的δ15N-AA模式是否与其氮代谢的独特方面有关？2)浮游植物生理的变化是否因氮营养的可用性、N形态的利用(铵、硝酸盐和混合)和/或其他生长条件独立地导致δ15N-AA的显著变化？浮游植物样本将从受控培养(例如，恒化器)实验和墨西哥湾和切萨皮克湾的实地研究中收集，特别是在接近单一物种的水华事件期间。利用新开发的分析方法，将首次产生关于浮游植物中精氨酸、天冬氨酸、谷氨酰胺和组氨酸等多N-AA的化合物和分子内δ15N的新知识。这项地面实况工作将促进对关键浮游植物物种产生的δ15N-AA模式的理解，这些浮游植物物种对生物泵和环境相关生理条件下的有害藻华至关重要。这项工作的预期结果将使新的应用和更复杂的营养位置分析，海洋生物泵的效率研究，以及使用自然档案中保存的氨基酸重建古海洋。该项目由生物和化学海洋学项目资助。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。