Nutrient Data for cruise DANA 6/21 (18 - 28 July 2021)

Water column samples were taken at 25 stations as conductivity-temperature-depth (CTD) casts along five transects during ten consecutive sampling days between 18 and 28 July 2021 on board RV Dana (DANA 6/21). Samples were collected in 10 L metal-free Niskin water samplers (Ocean Test Equipment; Fort Lauderdale, USA). Water samples for nutrient analysis were collected in acid-washed 100 mL HDPE (high-density polyethylene) bottles. The bottles were preconditioned three times with sample water before being filled. The samples were stored frozen at -20°C without filtration until analysis. Nitrite, phosphate, and silicate were measured on a SmartChem 200 discrete analyser (AMS Alliance, Rome, Italy) following the reagent concentrations for the manual method in Hansen and Koroleff (1999), with the inclusion of a 150 g L-1 solution of sodium dodecylsulfate as a dispersant for phosphate analysis. Nitrate was measured following the vanadium chloride reduction technique described by Schnetger and Lehners (2014). Community reference material for nutrients in seawater supplied by Kanso Technos Co. LTD, Japan, was used for quality control. Hansen, H.P., Koroleff, F., 1999. Determination of nutrients, in: Grasshoff, K., Kremling, K., Ehrhardt, M. (Eds.), Methods of Seawater Analysis. Wiley-VCH Verlag GmbH, Weinheim, Germany, pp. 159–228. https://doi.org/10.1002/9783527613984.ch10 Schnetger, B., Lehners, C., 2014. Determination of nitrate plus nitrite in small volume marine water samples using vanadium(III)chloride as a reduction agent. Marine Chemistry 160, 91–98. https://doi.org/10.1016/j.marchem.2014.01.0102021年7月18日至28日，在连续10个采样日期间，搭载“达纳号”（RV Dana，DANA 6/21）科考船，沿5条断面于25个站位开展电导率-温度-深度（conductivity-temperature-depth, CTD）剖面观测并采集水柱样品。样品采用10 L无金属尼斯金采水器（Ocean Test Equipment；美国劳德代尔堡）采集。用于营养盐分析的水样采集于经酸洗处理的100 mL高密度聚乙烯（high-density polyethylene, HDPE）瓶中，采样前需用待采水样预润洗3次后再灌装。所有样品未经过滤，便在-20℃条件下冷冻保存直至分析。 亚硝酸盐、磷酸盐与硅酸盐采用SmartChem 200型离散分析仪（AMS Alliance，意大利罗马）进行测定，试剂浓度参照Hansen与Koroleff（1999）提出的手工方法标准，其中磷酸盐分析环节额外添加150 g·L⁻¹的十二烷基硫酸钠溶液作为分散剂。硝酸盐的测定采用Schnetger与Lehners（2014）描述的三氯化钒还原法。本次分析采用日本Kanso Technos Co. LTD提供的海水营养盐质控参考物质开展质量控制。 Hansen, H.P., Koroleff, F., 1999. 营养盐的测定，载于：Grasshoff, K., Kremling, K., Ehrhardt, M.（主编），《海水分析方法》，Wiley-VCH Verlag GmbH，德国魏恩海姆，第159–228页。https://doi.org/10.1002/9783527613984.ch10 Schnetger, B., Lehners, C., 2014. 采用三氯化钒作为还原剂测定小体积海水样品中的硝酸盐与亚硝酸盐，《海洋化学》160卷，第91–98页。https://doi.org/10.1016/j.marchem.2014.01.010