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

马丁将在西北大西洋大陆边缘的一个深度样带上测定底栖生物通量和孔隙水中碳和相关溶质的浓度。建议的研究区域是71 W的100-2000m深度区间，该区域在物理上代表了大部分边缘。这一地区完整的深度样带将大大提高我们将边缘过程纳入全球化学循环定量模型的能力。拟议的测量将在几个方面不同于以往的边际通量测定。(1)通量室的部署将持续4天，比大多数快速积累的高通量沉积物的部署长2-3倍。这种增加的长度将定义这类沉积物中几个重要的过程。将对近海边缘沉积物中由大规模动物灌溉引起的溶质运移进行实地测量。碱度、戴尔- 13c（总co2）和溶解有机碳通量的信噪比将得到显著改善，从而为DOC和CaCO3的饱和以上水平溶解对底栖碳循环的贡献提供新的信息。(2)通量实验将在8个地点各进行一式两份，并将伴随广泛的原位微电极分析以及高分辨率和“标准”孔隙水采样。通量室和取心作业将通过潜水器进行，这样可以在一个相对较小的、视觉上均匀的区域内进行综合测量。测量的数量和组合将使对站点内变异性的评价优于过去的实验，增加对通量与水柱深度趋势的信心。(3)在较浅的站点（100-1000m），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（及其潜在的不良后果），设计了保持舱内氧气的设计，以保持氧气水平接近环境底水的水平。

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.