Collaborative Research: Metabolic Rates and Growth Efficiency Across Redox and Thermal Gradients: An Experimental Study to Constrain Biomass Production at Vents

尽管它们是深海热液系统食物网的基础，但人们对深海热液喷口区以地热/矿物来源的化学能为生的微生物的生长效率和其他基本代谢特征知之甚少。这项研究使用了一种新型的，流动的，实验室反应器设备来进行首次实验，研究在温度，压力（100到250巴）和深海热液系统的化学条件下微生物的生长速度和代谢效率。实验将通过测量反应器溶液中硝酸盐还原和氢氧化微生物的含氮呼吸产物，针对两种常见的深海排放口微生物的代谢过程。研究目标是确定氧化还原梯度对水热系统中硝酸盐还原和氨化作用的作用，利用同位素动力学同位素效应确定代谢率，并确定在H2/CO2摩尔比范围内的中温和嗜热厌氧微生物的生长效率。这项工作的更广泛影响包括在两个学科和实验室交叉培训一名研究生，以及在研究中纳入一名来自代表性不足的少数民族的学生。

Although they are the base of the food-web in deep sea hydrothermal systems, the growth efficiencies and other essential metabolic characteristics of microorganisms that live off chemical energy from geothermal/mineralogical sources in hydrothermal vent areas in the deep ocean are poorly known. This research uses a novel, flow through, laboratory reactor apparatus to run first-of-a-kind experiments looking at microbial growth rates and metabolic efficiencies at the temperatures, pressures (100 to 250 bars), and chemical conditions found in hydrothermal systems on the deep seafloor. Experiments will target the metabolic processes of two common deep sea vent microorganisms by measuring, in the reactor solutions, nitrogen-bearing respiratory products of nitrate-reducing and hydrogen-oxidizing microbes. Research goals are to determine the role of redox gradients on nitrate reduction and ammonification in hydrothermal systems, use isotopes to determine metabolic rates using kinetic isotope effects, and determine the growth efficiency of mesophilic and thermophilic anaerobic microbes at a range of H2/CO2 molar ratios. Broader impacts of the work include cross-training of a graduate student in two disciplines and laboratories and inclusion of a student from an under-represented minority in research.