Sea ice, brine and under ice water carbon dioxide (CO2) concentrations as dissolved inorganic carbon

During the ice stations, sea ice, brine/slush, snow and under-ice water sampling were collected for CO2 concentration measurement as dissolved inorganic carbon (DIC). Ice cores were collected using a Kovacs 9 cm diameter ice corer. The ice core for DIC was cut directly after retrieval with a stainless steel folded saw. The core was cut generally into 10 cm sections (20 cm when ice cores were higher than 200 cm) and put into zip-lock polyethylene bags. Care was taken to use laboratory gloves when collecting the cores. For brine sampling, partial core holes were drilled into the ice (so called sackholes), usually to a depth of 25 cm and 50 cm. At site with flooding, brine collection was not possible, and samples of the surface slush were collected instead. Slush was collected by plastic shovel. Snow samples were also collected. Under-ice water was collected with a Teflon water sampler (GL Science Inc., Japan) 1, 3, 5 m below the bottom of the sea ice. In addition, CTD water sampling was examined at each station. The cores were taken back to the ship, and transferred to the gas tight bag (GL Science Inc., Japan), and then ice was melted at about +4 degrees C in a refrigerator. Melted samples were sub-sampled for each component. The snow samples were treated in the same manner as the sea ice samples for further analysis. The dissolved inorganic carbon (DIC) of seawater was determined by coulometry [Johnson et al. 1985] using a coulometer (CM5012, UIC Inc., Binghamton, NY, USA). DIC measurement was calibrated with reference seawater materials (Batch AG; KANSO Technos Co., Ltd., Osaka, Japan) traceable to the Certified Reference Material distributed by Prof. A. G. Dickson (Scripps Institution of Oceanography, La Jolla, CA, USA). The standard deviation for DIC calculated from 20 subsamples taken from a reference seawater material (DIC = 2084.5 micro mol L-1) was 1.4 micro mol L-1.Data available: excel files containing sampling station name, dates, and DIC concentration.

在冰站作业期间，采集海冰、卤水、融雪泥浆、积雪及冰下海水样本，用于以溶解无机碳（dissolved inorganic carbon, DIC）为指标的二氧化碳浓度测量。冰芯采用直径9厘米的Kovacs型冰芯钻机采集。用于溶解无机碳检测的冰芯在取回后立即采用不锈钢折叠锯进行切割：冰芯通常被切割为10厘米长的分段（若单根冰芯长度超过200厘米，则分段长度调整为20厘米），随后装入密封聚乙烯自封袋中。冰芯采集过程中需全程佩戴实验室手套。卤水采样时，需在冰体上钻取局部孔眼（即所谓的袋状孔），钻孔深度通常设置为25厘米与50厘米；若冰站存在积水情况，则无法采集卤水，转而采集表层融雪泥浆样本，融雪泥浆采用塑料铲进行采集。同步采集积雪样本。冰下海水采用特氟龙材质采水器（GL Science Inc., 日本）采集，采样深度设定为海冰底部下方1米、3米与5米处。此外，各冰站均开展了CTD（温盐深剖面仪）采水作业。采集的冰芯被运回科考船，转移至气密袋（GL Science Inc., 日本）中，随后将冰置于约4℃的冰箱内进行融化。融化后的样本将分取子样本用于各组分的检测分析。积雪样本的前处理流程与海冰样本完全一致，以开展后续分析检测。海水溶解无机碳（DIC）采用库仑法[Johnson等，1985]进行测定，所用仪器为CM5012型库仑计（UIC Inc.，美国纽约州宾汉顿市）。DIC检测结果采用海水标准物质（批次AG；KANSO Technos Co., Ltd.，日本大阪市）进行校准，该标准物质可溯源至由A. G. Dickson教授（美国加利福尼亚州拉霍亚市斯克里普斯海洋研究所）分发的认证标准参考物质。从某一海水标准物质（DIC浓度为2084.5 μmol·L⁻¹）中分取20个子样本进行检测，计算得到的DIC检测标准偏差为1.4 μmol·L⁻¹。可用数据集：包含采样站名称、采样日期及DIC浓度的Excel文件。