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首页> 外文期刊>Environmental Science & Technology >Characterizing Phosphorus Speciation of Chesapeake Bay Sediments Using Chemical Extraction, ~(31)P NMR, and X-ray Absorption Fine Structure Spectroscopy
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Characterizing Phosphorus Speciation of Chesapeake Bay Sediments Using Chemical Extraction, ~(31)P NMR, and X-ray Absorption Fine Structure Spectroscopy

机译：使用化学萃取，〜（31）P NMR和X射线吸收精细结构光谱表征切萨皮克湾沉积物的磷形态

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摘要

Nutrient contamination has been one of the lingering issues in the Chesapeake Bay because the bay restoration is complicated by temporally and seasonally variable nutrient sources and complex interaction between imported and regenerated nutrients. Differential reactivity of sedimentary phosphorus (P) pools in response to imposed biogeochemical conditions can record past sediment history and therefore a detailed sediment P speciation may provide information on P cycling particularly the stability of a P pool and the formation of one pool at the expense of another. This study examined sediment P speciation from three sites in the Chesapeake Bay: (ⅰ) a North site in the upstream bay, (ⅱ) a middle site in the central bay dominated by seasonally hypoxic bottom water, and (ⅲ) a South site at the bay-ocean boundary using a combination of sequential P extraction (SEDEX) and spectroscopic techniques, including ~(31)P NMR, P X-ray absorption near edge structure spectroscopy (XANES), and Fe extended X- ray absorption fine structure (EXAFS). Results from sequential P extraction reveal that sediment P is composed predominantly of ferric Fe-bound P and authigenic P, which was further confirmed by solid-state ~(31)P NMR, XANES, and EXAFS analyses. Additionally, solution ~(31)P NMR results show that the sediments from the middle site contain high amounts of organic P such as monoesters and diesters, compared to the other two sites, but that these compounds rapidly decrease with sediment depth indicating remineralized P could have precipitated as authigenic P. Fe EXAFS enabled to identify the changes in Fe mineral composition and P sinks in response to imposed redox condition in the middle site sediments. The presence of lepidocrodte, vermiculite, and Fe smectite in the middle site sediments indicates that some ferric Fe minerals can still be present along with pyrite and vivianite, and that ferric Fe-bound P pool can be a major P sink in anoxic sediments. These results provide improved insights into sediment P dynamics, particularly the rapid remineratization of organic P and the stability of Fe minerals and the ferric Fe-bound P pool in anoxic sediments in the Chesapeake Bay.
机译：在切萨皮克湾，养分污染一直是挥之不去的问题之一，因为该海湾的恢复工作因时间和季节变化的养分来源以及输入和再生养分之间的复杂相互作用而变得复杂。响应所施加的生物地球化学条件，沉积磷（P）池的差异反应性可以记录过去的沉积物历史，因此详细的沉积物P形态可能提供有关P循环的信息，特别是P池的稳定性和一个池的形成，但以另一个。这项研究检查了切萨皮克湾三个地点的沉积物P形态：（ⅰ）上游海湾的北地点，（ⅱ）中央海湾的中间地点，该地点以季节性缺氧的底水为主，（ⅲ）南部的地点使用顺序P提取（SEDEX）和光谱技术相结合的海湾-海洋边界，包括〜（31）P NMR，P X射线吸收近边缘结构光谱（XANES）和Fe扩展X射线吸收精细结构（ EXAFS）。连续P提取的结果表明，沉积物P主要由铁结合的P和自生P组成，这由固态〜（31）P NMR，XANES和EXAFS分析进一步证实。此外，溶液〜（31）P NMR结果表明，与其他两个位置相比，中间位置的沉积物含有大量的有机P，例如单酯和二酯，但这些化合物随沉积深度而迅速减少，表明再矿化的P可以Fe EXAFS能够鉴定出自生的P。FeEXAFS能够识别中部沉积物中强加的氧化还原条件，从而响应Fe矿物成分和P汇的变化。中间部位沉积物中存在纤铁矿，ver石和铁蒙脱石表明，某些铁铁矿物质仍可与黄铁矿和Vivianite一起存在，并且与铁结合的磷矿池可能是缺氧沉积物中的主要磷汇。这些结果提供了更好的洞察沉积物磷动力学的见解，尤其是切萨皮克湾缺氧沉积物中有机磷的快速再矿化以及铁矿物质的稳定性以及铁矿中铁结合的磷库。

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  • 来源
    《Environmental Science & Technology》 |2015年第1期|203-211|共9页
  • 作者

    Wei Li; Sunendra R. Joshi; Guangjin Hou; David J. Burdige; Donald L. Sparks; Deb P. Jaisi;

  • 作者单位

    Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716, United States,Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, People's Republic of China;

    Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716, United States;

    Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States;

    Department of Ocean, Earth, and Atmospheric Sciences, Old Dominion University, Norfolk, Virginia 23529, United States;

    Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716, United States;

    Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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