The deviation from secular equilibrium between the natural radionuclide ²¹⁰Po (half-life: 138.4 d) and its radioactive grandparent ²¹⁰Pb (half-life: 22.3 y) has been used to examine particle export from the surface ocean. Here we combine ²¹⁰Po and ²¹⁰Pb activity results from three GEOTRACES transects: two transects of the North Atlantic Ocean (GA03: 15–40°N, and GA01: 40–60°N) and one transect of the South Pacific Ocean (GP16: 10–15°S), and estimate ²¹⁰Po export fluxes at the base of the primary production zone (PPZ) by assuming steady state (SS) without advection or diffusion of the isotopes. The SS ²¹⁰Po flux was sometimes lower at basin margins than at the open-ocean stations along the transects. High SS ²¹⁰Po flux estimations derived in the North Atlantic subtropical gyre may be associated with the atmospheric deposition of ²¹⁰Pb to the surface ocean. In this paper we also question the validity of the SS assumption and discuss the influence of vertical advection and diffusion on the overall ²¹⁰Po activity balance. The SS model may have underestimated the export flux of ²¹⁰Po at margin stations in the GA03 and GP16 transects and along the GA01 cruise track. We found that upwelling in the Peruvian coastal region and near the Greenland shelf had a dramatic impact on the estimated ²¹⁰Po flux balance. Vertical diffusion had limited influence on the ²¹⁰Po export fluxes along GA03 and GA01 in the North Atlantic whereas it added ²¹⁰Po export fluxes by as much as 190% in GP16 in the Pacific, especially at the shelf stations 1 and 4. Further, analysis of the partitioning coefficient suggested the importance of small particles in the scavenging of radionuclides. This suggests it is wise to sample small particles along with large particles to determine the ratio of the concentration of particulate organic carbon (POC) to ²¹⁰Po activity (POC/²¹⁰Po) for the lower limit of POC export flux estimations. Finally, the observation of the deficit of ²¹⁰Po relative to ²¹⁰Pb activity (²¹⁰Po/²¹⁰Pb < 1) in seawater concurrent with a deficit of ²¹⁰Po in particles contradicts our understanding of the conceptual ²¹⁰Po flux model, which assumes that ²¹⁰Po activity is more effectively removed from the surface ocean via particles than ²¹⁰Pb activity. While this observation deserves more attention, we propose two possible solutions: (1) the deficit of total ²¹⁰Po relative to ²¹⁰Pb activity in the surface ocean may be due to an input of ²¹⁰Pb activity instead of/concurrent with a relative removal of ²¹⁰Po activity via particle export; or (2) the particles collected may not be identical to the ones that have originally created the observed deficit in total ²¹⁰Po activity.

天然放射性核素²¹⁰ Po（半衰期：138.4 d）与其放射性祖父母²¹⁰ Pb（半衰期：22.3 y）之间的长期平衡偏差已用于检查从表层海洋中输出的粒子。在这里，我们结合了三个GEOTRACES样带的²¹⁰ Po和²¹⁰ Pb活度结果：北大西洋的两个样带（GA03：15–40°N和GA01：40–60°N）和南太平洋的一个样带（GP16） ：10–15°S），并通过假设稳态（SS）没有同位素的对流或扩散来估算主要生产区（PPZ）底部的²¹⁰ Po出口通量。SS ²¹⁰盆地边缘的Po通量有时比沿样带的开放海洋站低。在北大西洋亚热带回旋中得出的高SS ²¹⁰ Po通量估计值可能与²¹⁰ Pb到地表海洋的大气沉积有关。在本文中，我们还质疑SS假设的有效性，并讨论垂直对流和扩散对总体²¹⁰ Po活动平衡的影响。SS模型可能低估了GA03和GP16样带的边缘站以及GA01航迹的²¹⁰ Po的出口通量。我们发现，在秘鲁沿海地区和格陵兰陆架附近的上升流对估计的^210人产生了重大影响。宝通量平衡。垂直扩散对影响有限^210个沿GA03和GA01在北大西洋宝输出通量，而它加入^210个在GP16在太平洋宝输出通量幅度高达190％，特别是在货架站1和4。此外，分析分配系数的变化表明小颗粒在清除放射性核素中的重要性。这表明明智的做法是，对小颗粒和大颗粒进行采样，以确定POC出口通量估计值下限的颗粒有机碳（POC）浓度与²¹⁰ Po活性（POC / ²¹⁰ Po）的比值。最后，观察到²¹⁰ Po相对于²¹⁰ Po的赤字海水中的Pb活性（²¹⁰ Po / ²¹⁰ Pb <1）与颗粒中²¹⁰ Po的缺乏相矛盾，这与我们对概念性²¹⁰ Po通量模型的理解相矛盾，该模型假定²¹⁰ Po活性比颗粒更有效地从表层海洋中去除。²¹⁰ Pb活性。尽管这一观察值得更多关注，但我们提出了两种可能的解决方案：（1）表层海洋中相对于²¹⁰ Pb活性的总²¹⁰ Po的赤字可能是由于输入²¹⁰ Pb的活性而不是/同时去除了²¹⁰ Pb的活性²¹⁰通过粒子出口进行宝活动；或（2）收集到的颗粒可能与最初在²¹⁰ Po的总活性中产生观察到的缺陷的颗粒不同。