Unisense MicroProfiling System for High-Resolution Aqueous Geochemical Measurements

所要求的设备是Unisense的自动化微剖面系统（MPS），将允许以微米空间分辨率对水、沉积物、土壤和生物膜中的氧、氮物质、硫化物、氢、氧化还原和pH值进行化学测量。以下是需要MPS的研究课题：（1）确定现代微生物过程如何影响沉积物（如页岩）的微量金属成分。MPS将测量现代海岸沉积物中的原位地球化学分带，结合孔隙水和沉积物地球化学分析，显示痕量金属模式在埋藏过程中如何改变。反过来，这对于评估古代页岩的成分是否可以用来推断古海水成分是很重要的。(2)确定生物炭（热解碳）对全球元素循环、土壤化学和氧化还原特性以及污染物迁移的影响。MPS需要测量氧化还原条件快速变化的土壤上部颗粒尺度的氧化还原变化和微生物呼吸，以及旨在模拟生物炭在受控环境中迁移的实验室柱实验。 (3)通过在受控条件下对沉积物栖息群落进行水族馆研究，确定海洋沃茨中溶解氧降低对海底沉积物中动物大小和多样性的影响。MPS允许观察动物种群规模和多样性对氧气减少和硫化物增加的反应，这些反应可用于解释岩石记录中的微量化石数据。 (4)检查生命构成要素的周期（例如，碳、氮、硫）和关键金属（例如，铁）及其对深层地下水和温泉中可居住性的影响。MPS允许以高空间分辨率原位测量氧化还原条件，特别是在这种环境中缺乏数据的氮物质。(5)研究微生物形成矿物的机制以及它们如何影响矿物相变。MPS将使人们有可能收集的pH值，氧化还原条件，并在沉积物-水界面的环境和实验室水族馆的痕量气体浓度的配置文件。这些数据将与电子和同步加速器显微镜相结合，以提供前所未有的微米级生物矿化的图片。(6)描述加拿大北极冰川融水中的营养物质如何影响海洋微生物群落。MPS将通过确定底层沉积物的生物地球化学分带来扩展这些研究，从而阐明生物量及其同化营养物是如何处理的。这种水和沉积物柱数据集的配对将显示生物量如何保存在现代沉积物中，并最终了解地球历史上过去大规模冰川作用的影响（例如，“雪球地球”）关于海洋浮游植物的进化。

The equipment requested, an automated MicroProfiling System (MPS) from Unisense, will allow for chemical measurements of oxygen, nitrogen species, sulfide, hydrogen, redox and pH at micrometer spatial resolution in water, sediments, soils, and biofilms. The following are research topics that require the MPS: (1) Determining how modern microbial processes impact the trace metal composition of sediments, such as shales. The MPS will measure the in situ biogeochemical zonation in modern coastal sediment, which combined with the analyses of porewater and sediment geochemistry, shows how trace metal patterns are modified during burial. This is, in turn, important for assessing whether the composition of ancient shales can be used to infer paleo-seawater composition. (2) Ascertaining the influence of biochar (pyrolyzed carbon) on global elemental cycling, soil chemistry and redox properties, and contaminant transport. The MPS is needed to measure redox changes and microbial respiration at the grain scale in the upper part of soils where redox conditions change rapidly, and in laboratory column experiments that aim to simulate biochar migration in a controlled environment. (3) Establishing the influence of lowered dissolved oxygen in marine waters on animal size and diversity in seafloor sediments through aquaria studies where sediment-dwelling communities are held under controlled conditions. The MPS allows an observation of animal-population size and diversity responses to lowered oxygen and rising sulfide that can be used to interpret trace fossil data in the rock record. (4) Examining the cycles of life-constituting elements (e.g., carbon, nitrogen, sulfur) and critical metals (e.g., iron) and their impacts on the habitability in deep subsurface groundwaters and hot springs. The MPS allows for in situ measurements of redox conditions at a high spatial resolution, specifically nitrogen species for which there is a dearth of data in such environments. (5) Studying the mechanisms by which microbes form minerals and how they influence mineral phase transitions. The MPS will make it possible to collect profiles of pH, redox conditions, and trace gas concentrations at the sediment-water interface in both the environment and laboratory aquaria. This data will be combined with electron and synchrotron microscopy to provide an unprecedented picture of biomineralization at the micron scale. (6) Characterizing how nutrients in glacial meltwaters of the Canadian Arctic impact marine microbial communities. The MPS will extend these studies by determining the biogeochemical zonation of underlying sediments, thus elucidating how biomass and their assimilated nutrients are processed. This pairing of water and sediment column datasets will show how biomass is preserved in modern sediment, and ultimately to understand the effects of past periods of extensive glaciation in Earth's history (e.g., `Snowball Earth') on the evolution of marine phytoplankton.