Elemental Tracers of Carbon Export and Recycling in the RossSea

9418786戴蒙德该项目将分析罗斯海现有的一套沉积物捕集器和海底样品中的钡和其他难熔元素(铝、钠、钒、铁、钍和锡)，并评估钡作为生物生产力和向罗斯海海底碳出口的替代指标。这些分析直接关系到人为二氧化碳在全球不同碳库中分配的数量和速度的问题。如果“新的”大气碳在相对较短的时间内被封存在非大气水库中，那么预期的全球变暖将会减少；然而，任何全球变暖也有可能增加从非大气水库到大气的碳(和其他温室气体)通量，从而加剧预期的全球变暖。虽然目前对行星的反应知之甚少，但人们认为，海洋过程，特别是海洋肥力的变化以及海洋肥力和环流之间的相互作用，是这些问题的决定性因素。海洋碳库的时间变化与海洋生产力有关，必须从代理观测中推断出来。最广泛使用的替代品--有机碳、碳酸钙和蛋白石(二氧化硅)--的缺点是它们无法区分可变的保存率和可变的生产率。该项目将把这些替代物与通过水柱和沉积物中的钡的流量联系起来，并用难熔元素的数据来约束钡的回收程度。这项分析还将有助于确定罗斯海横向碳输入的强度和来源。这项研究的结果将与其他持续研究相结合，以便更好地了解罗斯海和整个南大洋的生物地球化学循环。***

9418786 Dymond This project will analyze an existing suite of both sediment trap and ocean bottom samples from the Ross Sea for barium and other refractory elements (aluminum, sodium, vanadium, iron, thorium, and tin), and evaluate barium as a proxy for biological productivity and carbon export to the seafloor of the Ross Sea. These analyses bear directly on the question of how much and how quickly anthropogenic carbon dioxide is distributed among the various global carbon reservoirs. If the "new" atmospheric carbon is sequestered in non-atmospheric reservoirs within a relatively brief period, then the expected global warming will be reduced; however it is also possible that any global warming enhances the flux of carbon (and other greenhouse gases) from non-atmospheric reservoirs to the atmosphere, enhancing the expected global warming. While little is currently known about the planetary response, it is thought that oceanic processes, particularly changes in ocean fertility and interactions between ocean fertility and circulation, are defining factors in these questions. Time changes in the oceanic carbon reservoir are related to ocean productivity, and must be inferred from proxy observations. The disadvantage of the most widely used proxies -- organic carbon, calcium carbonate, and opal (silicon dioxide) -- is that they cannot distinguish between variable preservation rates and variable productivity rates. This project will link these proxies with the flux of barium through the water column and in the sediment, and constrain the extent of barium recycling with the refractory element data. This analysis will additionally help define the strength and source of lateral carbon input to the Ross Sea. Results from this study will be integrated with other continuing studies to produce a better understanding of biogeochemical cycling in the Ross Sea and in the Southern Ocean in general. ***