Chemical Controls on Bioavailability of Riverine Particulate Phosphorus and Changes in Riverine Particulate Phosphorus Chemistry Across the Continent-Ocean Interface

对河流颗粒磷生物利用度的化学控制以及跨大陆-海洋界面河流颗粒磷化学的变化

• 批准号: 9406585
• 负责人: Kathleen Ruttenberg
• 金额: $ 28.8万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-15 至 1999-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9406585&HistoricalAwards=false
• 关键词: Chemical; Controls; Bioavailability; Riverine; Particulate

9406585 Ruttenberg The overall objectives of this proposal are (1) to use selective leaching procedure (the SEDEX Method) to identify and quantify the chemical from of particulate-P in the lower Mississippi and Atchafalaya Rivers, at the interface between the Mississippi River and the deltaic marine shelf, and in proximal surficial deltaic marine sediments; (2) to identify spatial and temporal controls on processes modifying particulate-P during riverine transport; and (3) to identify spatial and temporal controls on chemical modification at the continent-ocean interface. Phosphorus (P) is an essential nutrient which can limit biological productivity in fresh, brackish, and saline natural waters. P associated with particulate matter in natural waters will enhance biological productivity to the extent that the P can be assimilated. Determining the bioavailable P associated with particulate matter is essential for placing constraints on sources of P for biological cycling in aquatic systems. Bulk P concentration is not a useful parameter as P-speciation is required for assessment of the fraction of particulate P which is bioavailable. The SEDEX method separately quantifies Fe-P, authigenic sedimentary apatite (ASAP), (phases likely to control soluble, and therefore bioavailable-P in natural waters), organic- P, loosely sorbed-P, and detrital apatite. P-distribution in Riverine Suspended Particulate Matter (RSPM) will be determined at a series of river stations chosen to permit comparisons of input from agricultural versus industrial land and between the levied lower Mississippi and the Atchafalaya hard-wood swamps. Temporal variability will be assessed by re-visiting the river study sites seasonal. This work will be carried out in conjunction with ongoing USGS monitoring programs, which provided an array of valuable supporting data and a long-term record. The effect of estuarine processes on RSPM P-distribution will be examined by coupling field measurements with P-desorption experiments. The latter will cover the range of salinity observed in the estuary. P-distribution of RSPM determined before and after mixing should permit direct identification of solid-phase P-reservoirs which liberate soluble (and therefore bioavailable ) P to solution. These results will be compared to P-distribution of in situ RSPM from the estuary. The riverine source of bioavailable-P to the coastal ocean will be assessed by contrasting the P-distribution of RSPM from these two rivers with that in proximal surficial marine sediments, and by contrasting P-loading calculations of separately quantified RSPM P-reservoirs to P-burial rates in proximal shelf sediments. The work focusses on a globally significant system, mechanisms of transformation, and physical and chemical controls that should be broadly applicable.

9406585 Ruttenberg 该提案的总体目标是 (1) 使用选择性浸出程序（SEDEX 方法）来识别和量化密西西比河下游和阿查法拉亚河、密西西比河与三角洲海洋陆架之间的交界处以及近地表三角洲海洋沉积物中颗粒磷的化学成分； (2) 确定河流运输过程中颗粒磷改变过程的空间和时间控制； (3) 确定大陆-海洋界面化学变化的空间和时间控制。 磷 (P) 是一种必需营养素，可限制淡水、咸水和咸水天然水中的生物生产力。 与天然水中的颗粒物相关的磷将提高生物生产力，直至磷可以被同化。 确定与颗粒物相关的生物可利用磷对于限制水生系统生物循环磷的来源至关重要。 总体磷浓度不是一个有用的参数，因为评估生物可利用的颗粒磷的比例需要磷形态。 SEDEX 方法分别量化 Fe-P、自生沉积磷灰石 (ASAP)（可能控制天然水中可溶性磷的相，因此可生物利用磷）、有机磷、松散吸附磷和碎屑磷灰石。 河流悬浮颗粒物 (RSPM) 的 P 分布将在一系列河流监测站确定，这些监测站的选择是为了比较农业用地和工业用地以及密西西比河下游和阿查法拉亚硬木沼泽的投入。 将通过季节性重新访问河流研究地点来评估时间变化。 这项工作将与正在进行的美国地质调查局监测计划结合进行，该计划提供了一系列有价值的支持数据和长期记录。 河口过程对 RSPM P 分布的影响将通过现场测量与 P 解吸实验的耦合来检验。 后者将涵盖在河口观测到的盐度范围。 混合前后测定的 RSPM 的 P 分布应允许直接识别将可溶性（因此可生物利用的）P 释放到溶液中的固相 P 储库。 这些结果将与河口原位 RSPM 的 P 分布进行比较。 将通过将这两条河流的 RSPM P 分布与近端表层海洋沉积物中的 P 分布进行对比，并将单独量化的 RSPM P 储层的 P 负载计算与近端陆架沉积物中的 P 埋藏率进行对比，来评估沿海海洋生物可利用磷的河流来源。 这项工作的重点是具有全球意义的系统、转化机制以及应广泛适用的物理和化学控制。