Benthic Fluxes and Sediment Irrigation on the Continental Margin, N.W. Atlantic

小行星9503562 将在大西洋西北部大陆边缘的深度断面上测定碳和相关溶质的底栖通量和孔隙水浓度。拟议的研究区域是71 W处100- 2000 m的深度区间，该区域在物理上代表了大部分边缘。 一个完整的深度样带在这一地区将显着提高我们的能力，将边际过程中的全球化学循环的定量模型。 拟议的测量将不同于以前的通量确定的利润在几个方面。 (1)通量室的部署将持续4天，比快速积累的高通量沉积物中的大多数部署长2-3倍。这种长度的增加将确定这类沉积物中的几个重要过程。 将对近海边缘沉积物中大型底栖动物灌溉的溶质运移进行现场测量。 显着改善的信噪比碱度，dell-13 C（totalCO 2），溶解有机碳通量将实现，从而提供新的信息DOC和以上饱和层溶解的CaCO 3对底栖碳循环的贡献。(2)将在8个地点中的每一个地点进行两次通量实验，同时进行广泛的现场微电极剖面分析以及高分辨率和“标准”孔隙水取样。 通量室和取芯作业将通过潜水器进行，从而可以在相对较小、视觉均匀的区域进行综合测量。 测量的数量和组合将允许改进对现场内变化的评估，而不是在过去的实验中，增加通量与水柱深度趋势的置信度。 (3)在较浅的场地（100- 1000米），通量室部署长度的增加将导致室水中O2的大量消耗。 为了抵消这种影响（其潜在的不希望的后果），设计室以保持O2水平接近于环境底层水的水平。

9503562 MARTIN Benthic fluxes and pore water concentrations of carbon and related solutes will be determined on a depth transect of the continental margin in the northwest Atlantic ocean. The proposed study area is the depth interval from 100-2000m at 71 W, a region that is physically representative of much of the margin. A complete depth transect in this region will significantly advance our ability to incorporate margin processes in quantitative models of global chemical cycles. The proposed measurements will differ from previous flux determinations on margins in several respects. (1) Flux chamber deployments will be 4 days long, 2-3 times longer than most deployments in rapidly accumulating, high-flux sediments. This increased length will define several processes important in sediments of this type. In situ measurements will be made of solute transport by macroninfaunal irrigation in offshore margin sediments. Significant improvements in the signal-to-noise ratio in alkalinity, dell-13C (totalCO2), and dissolved organic carbon fluxes will be achieved thus providing new information on the contributions of DOC and above-saturation horizon dissolution of CaCO3 to the benthic carbon cycle. (2) Flux experiments will be carried out in duplicate at each of 8 sites, and will be accompanied by extensive, in situ microelectrode profiling and both high-resolution and "standard" pore water sampling. Flux chamber and coring operations will be carried out via submersible, allowing the combination of measurements to be made in a relatively small, visually homogeneous area. The number an combination of measurements will allow improved evaluation of intra-site variability over what has been possible in past experiments, increasing confidence in trends of flux vs. water column depth. (3) At shallower sites (100-1000m), the increased length of flux chamber deployments would lead to extensive depletion of O2 in chamber water. To counteract this effect (with its potentia l undesirable consequences are designed to maintain the O2 in chambers are designed to maintain the O2 level close to that of ambient bottom water.