Collaborative Research: GEOTRACES- Methods development and intercalibration for the 210 Pb and 210 Po radionuclide pair

自GEOSECS以来的过去三十年中，天然存在的Po 210-Pb 210天然放射性核素对在海洋及其边界的颗粒清除和碳通量研究中得到广泛应用。毫不奇怪，这种同位素对的测量已被指定为美国GEOTRACES相互校准倡议文件的原则和优先事项中的优先事项。微量元素和同位素的相互校准是U.S. GEOTRACES在头两到三年的最高优先事项。在这个项目中，特拉华州大学和韦恩州立大学的研究人员将进行系统的相互校准工作，以确保Pb 210和Po 210在GEOTRACES计划下得到准确测量。在2008年6月的第一次GEOTRACES Intercalibration巡航中，从2000米的校准深度收集了大量（250 L）过滤和酸化的海水，约12份Po 210-Pb 210等分试样。同样，使用具有各种过滤基质、孔隙率和过滤速率的原位泵，与其他GEOTRACES放射性核素一样收集颗粒等分试样。这些溶解的和颗粒状的等分试样已分发给参加Po 210-Pb 210相互校准的大约12个国际调查人员，他们按照自己的处理和放射性核素分析协议进行处理。这个项目的研究人员将领导对参与者进行相互比较和综合的工作。找出不一致之处并提出改进建议。拟议的工作将与已经获得资助的GEOTRACES PI密切协调，以相互校准其他粒子反应（如Th、Pa）或溶解（如Ra）放射性核素同位素。这一建议的更广泛影响与整个GEOTRACES计划以及Pb 210-Po 210同位素系统作为各种海洋学分支学科研究工具的重要性密切相关。该项目将（1）通过提供Po 210和Pb 210的收集和放射化学分析的用户手册来增强研究基础设施，（2）为研究生和本科生提供支持和培训，以及（3）在特拉华州大学的专用公共网站上广泛传播我们的研究。

Over the past three decades since GEOSECS, the naturally-occurring Po210-Pb210 natural radionuclide pair has had wide application in studies of particulate scavenging and carbon flux in the ocean and at its boundaries. Not surprisingly, measurement of this isotopic pair has been designated as a programmatic priority in the Principles and Priorities of the U.S. GEOTRACES Intercalibration Initiative document. Intercalibration of trace elements and isotopes is the highest priority for U.S. GEOTRACES during its first two to three years. In this project, researchers at the University of Delaware and Wayne State University will conduct a systematic intercalibration effort to ensure that Pb210 and Po210 will be accurately measured under the GEOTRACES program. On the first GEOTRACES Intercalibration Cruise in June 2008, a large integrated volume (250 L) of filtered and acidified sea water was collected from the 2000 meter calibration depth for about a dozen Po210-Pb210 aliquots. Likewise particulate aliquots were collected in common with other GEOTRACES radionuclides using in-situ pumps with various filter substrates, porosity and filtration rates. These dissolved and particulate aliquots have been distributed to about a dozen international investigators participating in the Po210-Pb210 intercalibration following their own protocols for processing and radionuclide analyses. The investigators on this project will lead the effort to intercompare and synthesize the participants? results to identify inconsistencies and recommend improvements. The proposed work will be closely coordinated with GEOTRACES PIs already funded to intercalibrate other particle-reactive (e.g. Th, Pa) or dissolved (e.g. Ra) radionuclide isotopes. The broader impacts of this proposal are closely linked to the GEOTRACES Program as a whole and to the significance of the Pb210-Po210 isotopic system as a research tool in a variety of oceanographic subdisciplines. The project will (1) enhance research infrastructure by providing a User's Manual for the collection and radiochemical assay of Po210 and Pb210, (2) provide for the support and training of graduate and undergraduate students, and (3) provide broad dissemination of our research on dedicated public websites at the University of Delaware.