Disequilibria between the long-lived parents and short-lived particle-reactive daughters have been extensively used over the past six decades as tracers and chronometers in aquatic systems. In particular, the particle-reactive progeny of Ra (Pb, half-life, T, = 22.3 years and Po, T = 138.4 days) have been widely utilized to quantify oceanic biogeochemical processes (e.g. elemental export fluxes, residence time and scavenging rate of particulate and dissolved Po and Pb, settling velocity of particles and remineralization rates of biogenic particulate matter) as well as analogs for stable Pb, key micronutrients (e.g., Cu, Zn, Fe), and lithogenic elements (e.g., Al, Th, Ti). Vertical profiles of Po and Pb from the deep-ocean water column have been published for over six decades that show disequilibrium between Po and Pb with Po/Pb activity ratio (AR) of >1.1 and/or < 0.9 in discrete deep-water layers, although secular equilibrium with AR of 1.0 ± 0.1 is expected. To understand this discrepancy, a critical and in-depth review of Po-Pb-Ra published data was conducted, scrutinizing the sample size, methodology, reagent blanks, statistical analysis, and data reduction. For each of the published data sets for water depths >1000 m, the total water column inventories and the average activities of dissolved, particulate, and/or total (= particulate + dissolved) Po, Pb, and Ra were calculated. The total water-column-based average Po activities follow the pattern: Pacific Ocean > Indian Ocean > Antarctica > Atlantic Ocean > Arctic Ocean. The (Po/Pb) AR in small particles (1–51 μm) shows the following trend: N. Atlantic > E. Pacific > Arctic, whereas the AR in large particles shows the following trend: E. Pacific > N. Atlantic > Artic. The fractionation factors calculated using inventories of Po and Pb, exhibit the following pattern: Pacific Ocean > Indian Ocean > Antarctica > Atlantic Ocean > Arctic Ocean. The inventory-based distribution coefficients (K) of Po and Pb are comparable, as opposed to consistently higher K for Po reported in the literature. From deep water and whole column inventories of Pb and Ra, disequilibrium was found ubiquitously, with a highly varying residence time of Pb. Average surface water concentrations of Pb in the global oceans were found to correlate with latitude and show an overall decrease in concentration from mid-latitudes to poles, similar to Pb fallout.

中文翻译：

---

基于库存的深海 210Po-210Pb-226Ra 不平衡评估及其作为生物地球化学示踪剂的新见解：六十年来研究的全球数据综合

在过去的六十年里，长寿的父母和短命的粒子反应女儿之间的不平衡已被广泛用作水生系统中的示踪剂和计时器。特别是，Ra 的粒子反应子代（Pb，半衰期 T = 22.3 年，Po，T = 138.4 天）已被广泛用于量化海洋生物地球化学过程（例如元素输出通量、停留时间和清除率）颗粒物和溶解的 Po 和 Pb 的含量、颗粒的沉降速度和生物颗粒物质的再矿化速率）以及稳定 Pb 的类似物、关键微量营养素（例如 Cu、Zn、Fe）和成岩元素（例如 Al、Th、钛）。深海水体中 Po 和 Pb 的垂直剖面已发表了 60 多年，表明在离散的深水层中 Po 和 Pb 之间存在不平衡，Po/Pb 活度比 (AR) >1.1 和/或 < 0.9 ，尽管预计 AR 为 1.0 ± 0.1 的长期平衡。为了了解这种差异，我们对 Po-Pb-Ra 发布的数据进行了批判性和深入的审查，仔细审查了样本量、方法、试剂空白、统计分析和数据缩减。对于水深 >1000 m 的每个已发布数据集，计算了总水柱库存以及溶解、颗粒和/或总（=颗粒 + 溶解）Po、Pb 和 Ra 的平均活度。基于水柱的平均Po活动总量遵循以下模式：太平洋>印度洋>南极洲>大西洋>北冰洋。小颗粒（1~51 μm）中的（Po/Pb）AR表现出以下趋势：北大西洋>东太平洋>北极，而大颗粒中的AR表现出以下趋势：东太平洋>北大西洋>北极。使用 Po 和 Pb 清单计算的分馏因子呈现以下模式：太平洋 > 印度洋 > 南极洲 > 大西洋 > 北冰洋。 Po 和 Pb 基于库存的分配系数 (K) 相当，而文献中报道的 Po 的 K 值始终较高。从深水和整个柱的 Pb 和 Ra 清单来看，不平衡现象随处可见，Pb 的停留时间变化很大。研究发现，全球海洋地表水中铅的平均浓度与纬度相关，并且从中纬度地区到极地，铅浓度总体下降，与铅沉降物类似。