Factors Influencing the Rates and Mechanisms of Phytoplankton-Mediated Hydrogen Sulfide Production in Contrasting Oceanic Regimes

痕量金属的海洋化学、它们与配体的络合作用以及它们与浮游植物的相互作用与硫的循环密切相关。特别是，微量金属的形态可能会受到各种形式的还原硫(硫化物)的深刻影响，即使在富氧的表层海洋中也是如此。虽然硫化物可能是由微生物还原溶解的硫酸盐产生的，但也有大量证据表明，某些种类的浮游植物也可能同时产生溶解硫化物和颗粒硫化物。在这项研究中，老道明大学的研究人员将使用迭代的实验室和现场方法，对海洋浮游植物产生硫化氢的速率和机制进行彻底的检查。他们将测量一些沿海和海洋物种在连续养殖中产生溶解硫化物和颗粒硫化物的速度，并检查不同的光、营养和痕量金属水平的影响。此外，他们还将评估硫同位素测量在量化生物和非生物生产硫化氢方面的作用。实验室研究将与现场测量结果进行比较。研究小组期望阐明和量化溶解硫化物和颗粒硫化物的主要产生机制，并评估其对地表水中痕量金属循环的影响。

ABSTRACTOCE-0136367The marine chemistry of trace metals, their complexation with ligands, and their interactions with phytoplankton are intimately linked with the cycling of sulfur. In particular trace metal speciation may be profoundly influenced by various forms of reduced sulfur (sulfides), even in the oxygen-rich surface ocean. While sulfides may be produced by the microbial reduction of dissolved sulfate, there is also abundant evidence that some species of phytoplankton may also produce both dissolved and particulate sulfide. In this study, researchers at Old Dominion University will conduct a thorough examination of the rates and mechanisms of hydrogen sulfide production by marine phytoplankton using an iterative laboratory- and field-based approach. They will measure the rates of production of dissolved and particulate sulfide by a number of coastal and oceanic species in continuous culture and examine the influence of variable light, nutrient, and trace metal levels. Additionally they will assess the utility of sulfur isotope measurements in the quantification of biotic and abiotic production of hydrogen sulfide. The laboratory studies will be compared to field measurements. The research team expects to elucidate and quantify the principal mechanisms of production of both dissolved and particulate sulfide and to assess the implications for the cycling of trace metals in surface waters.