I-129: A New Biogeochemical Tracer of Oceanographic Processes

I-129：海洋过程的新型生物地球化学示踪剂

• 批准号: 9529351
• 负责人: John Edmond
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-11-01 至 1998-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9529351&HistoricalAwards=false
• 关键词: 129; New; Biogeochemical; Tracer; Oceanographic

9529351 Edmond It is very important to develop non-conservative tracers, i.e. transient anthropogenic species sensitive to biological and geochemical processes going on in the oceanic water column. At present the only such species for which information is available is anthropogenic lead (Shen and Boyle, 1988). It is derived from automobile exhaust and, to a much lesser extent, from the smelting of sulfide ores and other high temperature processes. Thus its atmospheric sources is predominantly confined to the Northern Hemisphere. Lead is strongly reactive with biogenic particles. Hence the fate of the transient can be used to study solute- particle scavenging reactions with a high degree of resolution ( Sherrell and Boyle, 1986). What is lacking is a tracer directly involved in the cycle of organic carbon with a strong signal. 129I, which is released in tremendous quantity from nuclear fuel reprocessing plants, has the potential to fill this role. Initial results from measurements in the Norwegian-Greenland Sea, the overflows around Iceland, the Labrador Sea and the North Atlantic show that the isotope is enriched in surface waters, the overflows and the deep Greenland, Norwegian and Labrador Seas, i.e. similar to 3H at a comparable stage in its evolution. However the penetration depth into the main thermocline in the North Atlantic appears significantly greater suggesting biogenic diapycnal transport, consistent with the biophilic nature of iodine. Measurements of I-129/I-127 ratios in selected archived samples will be made to develop I-129 as a non-conservative tracer and establish limits for its interpretation in biologically active environments.

小行星9529351 开发非保守示踪剂，即对海洋水体中发生的生物和地球化学过程敏感的短暂人类物种，是非常重要的。目前，唯一有可用信息的此类物种是人为铅（Shen和波义耳，1988年）。它来源于汽车尾气，在较小程度上来源于硫化物矿石的冶炼和其他高温过程。 因此，其大气来源主要局限于北方半球。铅与生物颗粒反应强烈。 因此，瞬态的命运可用于研究具有高分辨率的溶质-颗粒清除反应（Sherrell和波义耳，1986）。缺乏的是直接参与有机碳循环的具有强信号的示踪剂。 从核燃料后处理厂大量释放的129 I有可能填补这一角色。 在挪威-格陵兰海、冰岛周围的溢流口、拉布拉多海和北大西洋进行测量的初步结果表明，该同位素在表层沃茨、溢流口和格陵兰、挪威和拉布拉多海的深海中富集，即类似于处于可比演化阶段的3 H。 然而，在北大西洋的主要温跃层的渗透深度似乎显着更大，这表明生物源的diapycnal运输，符合碘的亲生物性。 将对选定的存档样品中的I-129/I-127比率进行测量，以将I-129开发为非保守示踪剂，并确定其在生物活性环境中的解释限度。