I-129: A New Biogeochemical Tracer of Oceanographic Processes

9529351爱德蒙开发非保守示踪剂非常重要，即对海洋水柱中发生的生物和地球化学过程敏感的瞬时人为物种。目前，唯一可获得信息的这类物种是人为铅(Shenand Boyle，1988)。它来自汽车尾气，在较小程度上来自硫化矿石的冶炼和其他高温过程。因此，它的大气来源主要限于北半球。铅与生物微粒有很强的反应能力。因此，瞬变的命运可以用来研究高分辨率的溶质-粒子清除反应(Sherrell和Boyle，1986)。缺少的是一种直接参与有机碳循环的示踪剂，信号很强。核燃料后处理厂大量释放的129I具有填补这一角色的潜力。在挪威-格陵兰海、冰岛、拉布拉多海和北大西洋周围的溢流测量的初步结果表明，同位素在表层水、溢流和格陵兰、挪威和拉布拉多海的深海中富含，即在其演化的一个可比阶段类似于~3H。然而，对北大西洋主要温跃层的穿透深度似乎明显更大，这表明生物的昼夜运输，这与碘的亲生物性质相一致。将对选定的存档样本中的I-129/I-127比率进行测量，以开发I-129作为非保守示踪剂，并为其在生物活跃环境中的解释设定限制。

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.