Investigation of the Rate of Shelf-Basin Interaction in the Western Arctic Using Radium Isotopes: SBI Phase II

使用镭同位素研究北极西部陆架盆地相互作用速率：SBI 第二阶段

• 批准号: 0124872
• 负责人: David Kadko
• 金额: $ 44.83万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-01-15 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0124872&HistoricalAwards=false
• 关键词: Investigation; Rate; Shelf; Basin; Interaction

The largely landlocked Arctic Ocean receives input from the Pacific and Atlantic Ocean and from rivers draining the surrounding continents. These inflows are important sources of salt, heat, nutrients, sediment and organisms for the central basin. With the exception of a portion of the Atlantic Ocean contribution, these inputs must cross continental shelves where they are modified significantly by benthic, water column, and air-ice-ocean interactions. As a consequence of the cross-shelf transports, there are significant biogeochemical exchanges between the shelves and the central basin. However, we currently lack the information to quantify these exchanges. In order to address this lack, this project proposes as part of the western Arctic Shelf-Basin Interaction (SBI) Phase II program to apply an isotopic water mass tracer technique to assess the pathways and rates of exchange between the western Arctic shelves and the interior Arctic Ocean basin. The proposed technique uses the measured concentrations in the water column of the two naturally occurring radioisotopes 228Ra and 226Ra. Because 228Ra, which has a half life of 5.77 years, is derived solely from shelf sediments, it provides unambiguous evidence of the presence of shelf water. Its relative concentration in shelf and basin waters can therefore provide quantitative information on shelf-basin water transports. This technique is mature and has been used in shelf-basin exchange investigations in other regions. Results of a pilot research project carried out during the SBI Phase I program have demonstrated utility of this tracer technique in the western Arctic Ocean. For the proposed research, tracer data collected from vessels along transects through the study region will be analyzed within the context of nearshore and offshore field and modeling studies that focus on understanding cross-shelf transport. An emphasis will be placed on the role of mesoscale eddies in this transport. Where appropriate, the shorter-lived 224Ra with its 3.64-day half life will be measured at sea to supplement the dataset. Radium tracer data will also be collected whenever possible from other platforms such as moored arrays provided by other SBI investigators.

大部分被陆地包围的北冰洋接受来自太平洋和大西洋以及周围大陆的河流的输入。 这些流入是中央盆地盐、热、营养物、沉积物和生物的重要来源。 除了大西洋的一部分贡献外，这些输入必须跨越大陆架，在那里它们受到海底、水柱和空气-冰-海洋相互作用的显著影响。 由于跨陆架输送，陆架与中央海盆之间存在着重要的地球化学交换。 然而，我们目前缺乏量化这些交流的信息。 为了解决这一问题，该项目建议作为北极西部陆架-海盆相互作用（SBI）第二阶段计划的一部分，应用同位素水团示踪技术来评估北极西部陆架和北冰洋内陆海盆之间的交换路径和速率。 该技术使用两种天然存在的放射性同位素228 Ra和226 Ra在水柱中的测量浓度。 由于228 Ra的半衰期为5.77年，仅来自陆架沉积物，因此它提供了陆架水存在的明确证据。 因此，其在陆架和盆地沃茨中的相对浓度可以提供有关陆架-盆地水输送的定量信息。 该技术已成熟，并已在其他地区的陆棚-海盆交换研究中得到应用。 在履行机构第一阶段方案期间进行的一个试点研究项目的结果表明，这种示踪技术在北冰洋西部的效用。 对于拟议的研究，从船舶收集的示踪剂数据沿着横断面通过研究区域将在近岸和近海领域和建模研究，重点是了解跨大陆架运输的背景下进行分析。 重点将放在中尺度涡旋在这种运输中的作用。 在适当的情况下，将在海上测量半衰期为3.64天的寿命较短的224 Ra，以补充数据集。 还将尽可能从其他平台收集镭示踪剂数据，如SBI其他调查人员提供的系泊阵列。