Evaluating the Effects of High Particulate Fluxes on Chemical Processes Occurring at the Amazon River/Ocean Boundary (Renewal)

该提案是对现有赠款“评估亚马逊河/海洋边界高颗粒通量的影响”的更新，该赠款是AmasSeds（多学科亚马逊陆架沉积物研究）项目的一部分。成功地完成了对亚马逊大陆架的三次研究巡航（1989年8月；1990年2月和1990年5月；1991年11月）。通过时间序列方法来了解亚马逊河/海洋边界活跃的化学、物理和地质过程，研究人员能够解决河流流量、潮汐再悬浮、当地风应力和沿海洋流强度对颗粒相关过程的可变影响。具体研究内容包括：1)评价悬沙浓度对营养物和碳的生物吸收和再生的影响；2)粒子和沉积物向水柱释放的镭同位素及其在跟踪海底/水柱交换过程中的应用；3)清除大陆架水域的颗粒活性元素；4)河/海混合过程中的铀循环；5)基于碳分布和稳定同位素数据追踪亚马逊陆架的生物和物理过程。对水柱和海底放射性示踪剂的测量使研究人员能够在不同的时间尺度（从几天到几百年）上描述许多这些过程。该提案要求额外支持两年的研究，这将用于完成数据分析，建立个人数据集，对初步结果进行建模，并将现场测量与参与该项目的其他研究小组相结合。

This proposal is a renewal for the existing grant entitled "Evaluating the Effects of High Particulate Fluxes at the Amazon River/Ocean Boundary," which is part of the AmasSeds (A Multi- Disciplinary Amazon Shelf SEDiment Study) Project. Three research cruises to the Amazon shelf (August 1989; February, 1990; and May 1990; and November, 1991) have been completed successfully. Time series approach to understanding the chemical, physical, and geological processes active at the Amazon River/ocean boundary enables the investigators to resolve the variable influences of river discharge, tidal resuspension, local wind stress, and the intensity of coastal currents on particle-associated processes. The specific topics of research described in this proposal include: 1) evaluating the effects of suspended sediment concentration on the biological uptake and regeneration of nutrients and carbon; 2) the release of radium isotopes to the water column from particles and sediments and their use in tracking seabed/water column exchange processes; 3) scavenging of particle-reactive elements from continental shelf waters; 4) uranium cycling during river/ocean mixing; and 5) tracing biological and physical processes on the Amazon shelf based on the distribution of carbon and stable isotopic data. Measurements of radioactive tracers in the water column and seabed enable investigators to characterize many of these processes on a variety of time scales (ranging from days to hundreds of years). This proposal requests support for two additional years of research, which will be used to complete data analyses, work up individual data sets, model the initial results, and integrate the field measurements with the other research groups taking part in the project.