Fate of Metals Associated with Marine Biogenic Debris

生物碎屑的通量通常被认为是水生系统中金属垂直迁移的主要载体。但是，对这些过程进行定量模拟的努力受到限制，因为关于大多数金属在生物碎屑中保留时间的数据库不足，特别是在不同微生物分解条件下。本研究包括一系列的放射性示踪剂实验，在不同的微生物降解条件下，测量了13种金属在浮游植物、桡足类、尾尾动物、毛齿动物以及浮游动物粪便颗粒、甲壳类动物蜕皮和幼虫的体内的滞留时间。金属生物动力学和途径将研究从溶解和摄入来源积累的金属。浮游植物中的金属区隔将被评估，以帮助了解食草动物摄入的命运。将在美国东北海岸附近建立和测试一个简单的模型，以量化不同形式的生物碎屑在调节金属通量方面可能发挥的作用。生物碎屑的分解和各类碎屑中的金属通量将在SEEP计划部署的沉积物捕集器中捕获的材料中进行测量。金属分析将使用国家同步加速器光源的x射线微探针设备。

The flux of biogenic debris has often been implicated as major vector in the vertical transport of metals in aquatic systems. However, efforts to model quantitatively these processes have been limited by an inadequate data base on the retention times of most metals in biogenic debris particularly under different conditions of microbial decomposition. This study includes a series of radiotracer experiments in which the retention times of thirteen metals will be measured in phytoplankton, copepods, appendicularians, and chaetognaths as well as zooplankton fecal pellets, crustacean molts, and larvacean houses under different condition of microbial degradation. Metal biokinetics and pathways in organisms will be studied for metals accumulated from dissolved and ingested sources. Metal compartmentalization in phytoplankton will be assessed to help understand the fate of ingested in herbivores. A simple model to quantify the roles that different forms of biogenic debris can play in mediating the flux of metals will be constructed and tested off the NE US coast. Decomposition of biogenic debris and metal flux in individual types of debris will be measured in material caught in sediment traps deployed for the SEEP program. Metal analyses will employ the X-ray microprobe facility of the National Synchrotron Light Source.