Trace metal and metal isotope biogeochemistry

我的研究项目的主要目的是通过使用微量金属和稳定同位素地球化学来增加我们对地球上生命重要的生物地球化学循环的理解。除了金属在环境中的固有重要性（即它们作为营养物或毒素的作用）之外，金属的化学性质往往与重要的环境过程有关，或在这些过程中起控制作用。在一个不断变化的世界里，人类活动扰乱了许多自然循环，并将对我们的食物来源、健康和气候产生影响，了解环境中的金属就显得尤为重要。新的分析进展为研究许多金属的稳定同位素分馏打开了大门。同位素特征是识别源汇和理解生物地球化学循环的有力工具。我的研究项目将金属生物地球化学研究与自然金属同位素变化的创新研究相结合。我的研究计划的两个主要目标是：(1)环境中的金属污染物和(2)微量金属的海洋生物地球化学。(1)的主要重点将是汞的研究。汞是一种全球分布的剧毒污染物。许多汞的自然循环尚不清楚，需要新的方法来更好地跟踪汞的来源和环境中的转化。B.A. Bergquist博士最近证明，汞同位素经过独特的同位素分选，为直接跟踪和了解环境中的汞循环提供了不可磨灭的指纹。这些发现为追踪汞在环境中的迁移和生物积累铺平了道路。(2)的目标之一将是提高我们对海洋铁的来源和生物地球化学循环的认识。铁是海洋中一种至关重要的微量营养素，通过影响海洋的碳循环在气候变化中起着根本作用。伯格奎斯特博士的研究项目将铁的浓度和物种形成研究与铁的同位素特征结合起来，以深入了解海洋中铁的来源和循环。

The primary aim of my research program is to increase our understanding of the biogeochemical cycles that are important for life on Earth through the use of trace metal and stable isotope geochemistry. Besides the inherent importance of metals in the environment (i.e., in their roles as nutrients or toxins), the chemistry of metals is often linked to, or plays a controlling role in, important environmental processes. Understanding metals in the environment is especially important in a changing world where human activities are perturbing many natural cycles and will have impacts on our food sources, health, and climate. New analytical advancements have opened the door for investigation of stable isotope fractionation of many metals. Isotopic signatures are powerful tools for identifying sources and sinks and for understanding biogeochemical cycling. My research program combines research on metal biogeochemistry with innovative studies of natural metal isotopic variations. The two primary objectives of my research program are (1) Metal Contaminants in the Environment and (2) The Marine Biogeochemistry of Trace Metals. The main focus of (1) will be the study of mercury. Mercury is a globally distributed and highly toxic pollutant. Much of the natural cycle of Hg is not well understood and new approaches are necessary to better track Hg sources and transformations in the environment. Dr. B.A. Bergquist recently demonstrated that Hg isotopes undergo unique isotopic fractionation that provides an indelible fingerprint for directly tracking and understanding Hg cycling in the environment. These findings pave the way for tracing the mobility and bioccumulation of the Hg in the environment. One of the goals of (2) will be to improve our understanding of the sources and biogeochemical cycling of iron in ocean. Iron is a vital micronutrient in the ocean and plays a fundamental role in climate change by influencing the carbon cycle of the ocean. Dr. Bergquist's research program combines both concentration and speciation studies of Fe with Fe isotopic signatures to gain insight into the sources and cycling of Fe in the ocean.