Nitrogen Cycling and Particle Dynamics in the Sargasso Sea: The Use of 15N Natural Abundances as an In-Situ Tracer

这个项目是对开放海洋中氮和颗粒通量之间相互作用的研究的更新。该研究的特点是在百慕大东南60公里处的一个地点采用时间序列方法，并检查氮同位素比率作为原位示踪剂。迄今为止的结果已经提供了350米以上的颗粒通量的季节记录以及上层海洋悬浮和下沉颗粒的氮同位素值。拟议的研究集中在几个关键问题上：1)与其他新产量的测量相比，公海500米以上的颗粒通量的大小如何，它们的季节和年际变化是什么？2)“新”氮的来源是什么？它们的季节、年际和区域变化？3)透光区悬浮粒子是如何产生下沉粒子的？(4)如果有的话，在透光区以下的悬浮粒子和下沉到该区域的粒子之间的耦合是什么性质的？//

This project is a renewal of an investigation into the interaction between nitrogen and particle fluxes in the open ocean. The study features a time-series approach at a site 60 km southeast of Bermuda and the examination of nitrogen isotopic ratios as an in situ tracer. Results to date have provided a seasonal record for particle flux in the upper 350m and nitrogen isotope values for both suspended and sinking particles in the upper ocean. The proposed research focuses on several keu questions: 1) How does the magnitude of particle fluxes in the upper 500 m of the open ocean compare with other measures of new production and what is their seasonal and interannual variability? 2) What are the sources of "new" nitrogen to the euphotic zone and their seasonal, interannual, and regional variability? 3) How are sinking particles derived from suspended particles in the euphotic zone? 4) What is the nature of the coupling, if any, between suspended particles below the euphotic zone and particles sinking to this region?//