KOK1606_14C-NPP_2020-03-04_V1.0

Cruise Name: KOK1606, Gradients 1.0. Project: Simons Foundation - Gradients NPSG Standard HOT protocols were used to measure in vitro primary productivity (PP) via the 14C radiotracer method [Karl et al., 1996]. Water samples were collected from 15m before dawn and incubated on deck in incubators screened to ~50% of surface irradiance and plumbed with flow through surface seawater for temperature regulation. Duplicate 500-ml bottles were incubated in the incubator for ~12hr and 24hr, light bottles were paired with dark bottles. Parallel samples were taken in duplicate to examine the influence of reduced light on PP for all stations. Duplicate 500-ml bottles were incubated inside mesh bags that reduced the light availability to ~25%. A time zero sample was taken at each station to ensure acidification was complete. Following dawn to dusk or dawn to dawn incubations, each sample was filtered onto a 25mm glass fiber filter. Filters were acidified with 1 ml of 2N hydrochloric acid in a fume hood for 12 hr to remove inorganic 14C after which 10 ml of Ultima Gold scintillation fluid was added to each sample. Radioactivity was determined using a Perkins Elmer 2600 liquid scintillation counter. The rate of PP was calculated by multiplying the percent of carbon labeled by the total carbon available for photosynthesis (e.g. dissolved inorganic carbon, DIC, calculated from SST and salinity measured at each station as per Lee et al. [2006]) and dividing by incubation time (t = 1 day). Rate measurements in light bottles were corrected to remove the rate measured in parallel dark bottles. Abbreviations for rate measurements are in the variable metadata. All rates are in units mg C m-3; ‘stdev’ refers to the standard deviation of duplicates for each incubation type, whereas ‘stdev-p’ refers to the propagated standard deviation. NaN’s represent stations or samples where rate measurements were not conducted.航次名称：KOK1606，梯度计划1.0（Gradients 1.0），项目隶属于西蒙斯基金会（Simons Foundation）的Gradients NPSG标准项目。研究采用标准HOT规程，通过14C放射性示踪法[Karl等，1996]测定体外初级生产力（Primary Productivity，PP）。于黎明前从15米水深采集水样，将水样置于甲板培养箱中培养，培养箱滤除约50%的表面辐照度，并通过流通表层海水实现温度调控。设置两组500毫升重复样瓶，分别培养约12小时与24小时，光照培养瓶与暗培养瓶配对设置。为探究弱光对初级生产力的影响，在所有站位设置平行实验组：将500毫升重复样瓶置于网袋内，使光照可及性降至约25%。每个站位均采集零时对照样本，以确保酸化过程完全。培养时长为黎明至黄昏或黎明至黎明，培养结束后，将每个样本过滤至25毫米玻璃纤维滤膜上。在通风橱中用1毫升2N盐酸对滤膜酸化12小时，以去除无机14C，随后向每个样本加入10毫升Ultima Gold闪烁液。使用Perkins Elmer 2600型液体闪烁计数器测定放射性活度。初级生产力速率通过以下公式计算：将标记碳的百分比乘以可用于光合作用的总碳量（例如根据每个站位的海表温度（Sea Surface Temperature，SST）与盐度计算得到的溶解无机碳（Dissolved Inorganic Carbon，DIC），计算方法参照Lee等[2006]），再除以培养时长（t=1天）。光照培养瓶的速率测量值需进行校正，以扣除平行暗培养瓶测得的速率。速率测量的缩写详见变量元数据。所有速率的单位为mg C m⁻³；‘stdev’指代每种培养类型的重复样本的标准偏差，而‘stdev-p’指代传播得到的标准偏差。NaN值代表未开展速率测量的站位或样本。