Depth profiles of suspended dissolved and particulate 232Th, 230Th, and 231Pa from R/V Knorr KN199-04, KN204-01, subtropical North Atlantic Ocean from 2010-2011 (U.S. GEOTRACES NAT project)

<p><strong>DMO NOTE on GNAZT Suspended Particulate Th/Pa:</strong><br /> - version 4 served on 29 Sept 2015; combined both dissolved and particulate Th &amp; Pa datasets into one.<br /> <strong><span style=\"background-color:#FFA07A\">See dataset \"</span><a href=\"http://www.bco-dmo.org/dataset/3847\"><span style=\"background-color:#FFA07A\">GT10-11 - Dissolved and Particulate Th and Pa</span></a><span style=\"background-color:#FFA07A\">\"</span></strong><br /> - version 3: none<br /> - version 2: 8 Aug. 2014<br /> - version 1: 31 Jan. 2013</p> <p><strong>Notes:</strong></p> <p>This data refers to the \"suspended\" size fraction of seawater particles (written with the suffix \"_susp\"). The particulate samples were collected by in-situ pumping over paired 0.8?m Pall Supor800 polyethersulfone filters behind a 51 ?m Sefar polyester mesh prefilter (See sampling Methodology below for details). Analysis of the paired Supor filters represents a particle size class approximating 0.45-51 µm (Bishop et al. 2012), while the top filter alone represents 0.8-51 µm and it is this size class referred to here as \"suspended\". We measured a select number of top and bottom filters separately for radionuclides and found that the bottom filters had radionuclide levels that were indistinguishable from clean filter process blanks. Therefore whether or not samples were analyzed as top and bottom paired, or the top filter alone, we refer to the particle size class represented as 0.8-51 µm.</p> <p>Radionuclide concentrations are given as the mass of radionuclide contained in a given volume of pumped seawater: femtograms (fg = 10-15 g) radionuclide per kilogram (kg) seawater for 230Th and 231Pa, and picograms (pg = 10-12 g) radionuclide per kg seawater for 232Th. Sample size was measured by volume (liters) of seawater pumped by mass flow controllers on the in-situ pumps, but we converted seawater volume to seawater mass using a fixed seawater density of 1.025 kg/L. The units are written simply as fg/kg and pg/kg. Note that the counterpart radionuclide data in the dissolved phase (&lt;0.45 µm) from this CRUISE are also reported in fg and pg per kilogram of seawater. Concentrations below detection are listed as ‘bdl’.</p><strong>GNAZT悬浮颗粒物钍（Thorium, Th）与镤（Protactinium, Pa）相关数据DMO备注：</strong><br />- 第4版于2015年9月29日发布，将溶解态与颗粒态Th、Pa数据集合并为单一数据集。<br /><strong>请参阅数据集"GT10-11——溶解态与颗粒态钍和镤"（<a href="http://www.bco-dmo.org/dataset/3847">）</a></strong><br />- 第3版：无；<br />- 第2版：2014年8月8日；<br />- 第1版：2013年1月31日。<br /><br /><strong>备注：</strong><br /><br />本数据集对应海水颗粒物的"悬浮"粒径组分（命名后缀为"_susp"）。颗粒态样品通过原位泵采获得：采集时使用配对的0.8μm Pall Supor800聚醚砜滤膜，其上游加装51μm Sefar聚酯网预过滤器（详细采样方法见下文）。对配对Supor滤膜的分析对应粒径范围约为0.45~51μm的颗粒物组分（Bishop等，2012）；而仅使用上游滤膜时，对应粒径范围为0.8~51μm，本数据集所指的"悬浮"颗粒物即为此粒径区间。我们对部分样品的上下滤膜分别进行了放射性核素分析，结果显示下游滤膜的放射性核素水平与空白滤膜处理本底无显著差异。因此无论样品采用配对滤膜分析还是仅采用上游滤膜分析，本数据集所指代的颗粒物粒径均为0.8~51μm。<br /><br />放射性核素浓度以单位体积抽滤海水中所含放射性核素的质量表示：230钍（230Th）与231镤（231Pa）的浓度单位为飞克（femtogram，fg=10^-15 g）每千克海水，232钍（232Th）的浓度单位为皮克（picogram，pg=10^-12 g）每千克海水。样品体积通过原位泵上的质量流量控制器记录的抽滤海水体积（升）确定，我们采用固定海水密度1.025 kg/L将体积换算为海水质量，因此浓度单位简写为fg/kg与pg/kg。需注意，本航次中溶解态组分（<0.45 μm）的对应放射性核素数据同样采用fg和pg每千克海水为单位。未检出的浓度值标注为‘bdl’。