Burial and Preservation of Phosphorus in Marine Sediments: Response to Bottom Water Oxygenation

小行星9415563 这项研究将研究底层水氧浓度对海底成岩过程和海洋沉积物中磷元素通量的影响。 研究的重点源于初步数据，表明海洋沉积物中磷的整体埋藏和保存在很大程度上取决于沉积物上覆的沃茨中的氧浓度。 这些研究表明，缺氧的底层沃茨增强了沉积物中磷的再生，降低了整体埋藏效率。 如果这种效应能够得到证实，它对沿海地区的富营养化和P的长期循环具有重要意义，特别是在广泛的海洋缺氧期间。 将使用现场海底通量室、孔隙水和沉积物测量，对墨西哥湾和大普吉特海峡区域缺氧和好氧底层沃茨覆盖的地点进行检查。将通过现场底栖室实验确定P和相关元素的稳态通量。底栖通量将与沉积物埋藏通量相结合，以计算不同研究地点的P埋藏效率。 这项研究的一个主要目标是确定负责磷的埋藏和保存的机制，以及它们在存在和不存在氧气的情况下如何不同。 将特别注意的过程可能敏感的变化氧化还原条件，如细菌和溶解铁的P循环。在现场和随后的实验室研究中收集的数据将被整合到一个数值传输反应模型，以约束早期磷成岩作用的动力学。研究结果将用于评估沉积物磷通量变化对长期全球海洋生产力的潜在影响。

9415563 INGALL This research will study the effect of bottom water oxygen concentration on seafloor diagenetic processes and elemental fluxes of phosphorous in marine sediments. The focus of the research stems from preliminary data suggesting that the overall burial and preservation of phosphorus in marine sediments is strongly dependent on the concentration of oxygen in waters overlying the sediments. These studies indicate that oxygen depleted bottom waters enhance phosphorus regeneration from sediments, diminishing overall burial efficiency. If this effect can be verified it has important implications for eutrophication in coastal regions and for the long term cycling of P especially during periods of widespread ocean anoxia. Sites overlain by anoxic and oxic bottom waters in the Gulf of Mexico and the greater Puget Sound region will be examined using in situ benthic flux chambers, pore water and sediment measurements. Steady state fluxes of P and associated elements will be determined from in situ benthic chamber experiments. Benthic fluxes will be combined with sediments burial fluxes in order to calculate P burial efficiencies for the different study sites. A major objective of this research is to identify the mechanisms responsible for the burial and preservation of phosphorus and how they may differ in the presence and absence of oxygen. Particular attention will be paid to processes potentially sensitive to changing redox conditions such as the cycling of P by bacteria and dissolved iron. Data gathered during the field and subsequent lab studies will be integrated into a numerical transport reaction model in order to constrain the kinetics of early phosphorus diagenesis. The results will be used to evaluate the potential effects of variations in sedimentary P flux on long term global marine productivity.