Advective Controls on Organic Carbon Export and Burial on the Northwest Atlantic Margin

越来越多的证据表明，海洋颗粒有机质(OM)受到海底洋流的广泛再分配，因此在给定沉积位置的物质可能基本上是预先老化的，并且远离其形成地点。使有机质源和汇在空间和时间上解耦的过程可能在大陆边缘特别普遍，在那里颗粒可以横向平流向下和沿斜坡，并最终输出到海洋内陆。伍兹霍尔海洋研究所的研究人员汇集了他们在地球化学、沉积学和物理海洋学方面的专业知识，以记录西北大西洋边缘的这些过程。从2004年春季开始，一系列系泊的物理海洋仪器和协调的船上测量将以前所未有的详细程度确定深海西部边界流的动态及其与墨西哥湾流的相互作用。在这个项目中，研究人员将使用透射仪增加系泊设备，并收集沉积物、沉积物捕捉器样本和悬浮颗粒进行详细的地球化学、同位素和矿物学分析，使他们能够限制通过横向平流输送的颗粒和有机物的性质、来源、年龄和通量，并帮助确定其最终的沉积命运。更广泛的影响将是能够更好地确定可能受到类似影响的其他领域，从而确立其全球意义。如果这些过程普遍存在，这一发现将对我们理解全球碳循环具有重要意义，因为假设的海底“风暴”的运输机制是受气候控制的。识别诊断沉积物和有机质积累模式的能力也可以在沉积记录中确定，并在气候变化的背景下得到明确的解释。

ABSTRACTOCE-0425677A growing body of evidence indicates that oceanic particulate organic matter (OM) is subject to extensive redistribution by bottom currents so that material at a given depositional location may be substantially pre-aged and remote from its site of formation. Processes that impart spatial and temporal decoupling of OM sources and sinks may be particularly prevalent on continental margins where particles can be laterally advected down- and along-slope, and ultimately exported to the ocean interior. Researchers at Woods Hole Oceanographic Institution have pooled their expertise in geochemistry, sedimentology and physical oceanography to document these processes on the N.W. Atlantic margin. Beginning in Spring 2004, an array of moored physical oceanographic instrumentation and coordinated shipboard measurements will establish in the dynamics of the Deep Western Boundary Current and its interactions with the Gulf Stream in unprecedented detail. For this project, the researchers will augment the moorings with transmissometers and collect sediments, sediment trap samples and suspended particles for detailed geochemical, isotopic and mineralogical analyses, permitting them to constrain the nature, provenance, age and fluxes of particles and organic matter transported via lateral advection and to help establish its ultimate depositional fate. A broader impact will be a better ability to identify other areas that may be similarly affected, and hence to establish its global significance. If these processes are widespread, this finding would have important implications for our understanding of the global carbon cycle since the hypothesized transport mechanism of benthic "storms" is climatically controlled. An ability to recognize diagnostic sediment and OM accumulation patterns could also be identified in the sedimentary record and unambiguously interpreted in the context of climate change.