CTD-associated variables, bottle salinity measurements, oxygen titrations, nutrient analyses, biogeochemical/biological variables, and DIC chemistry variables from R/V Thomas G. Thompson cruise TN376 from January to March 2020

These data are part of the NSF project \"Collaborative Research: Biogeochemical and Physical Conditioning of Sub-Antarctic Mode Water in the Southern Ocean.\" Specifically, these are the discrete bottle data from cruise TN376 aboard R/V Thomas G. Thompson, which sailed from Cape Town, South Africa (22 January 2020) to the Southern Ocean and returned to Mauritius (3 March 2020). The purpose of the project was to define the processes that condition SubAntarctic Mode Water formed at the SubAntarctic Front in the Southern Ocean. The cruise track took us southeast from Cape Town for our first shakedown station at 38°35'S x 024°E, a station which was ultimately canceled due to heavy weather conditions. Two days out of Cape Town, the coupler between the ship's number three main engine and generator broke. This meant the ship only had one main engine, with an associated generator, plus two smaller engines/generators for all power needs. With the loss in redundancy, this meant we had to cut our cruise plans short, in order to stay within several hundred miles of Durban, SA, such that the ship could go in for repair once a replacement coupler could be found. This also meant we had to abandon the planned meridional transect that was to be done on this trip, since the travel to the shipyard, the repair, and return to the next station took over a week of sampling out of the cruise, and our proximity to Durban (and long distance from the Crozet Islands) meant we couldn't possibly accomplish the meridional transect and make it to Mauritius within the UNOLS ship schedule. We added the meridional transect to the second cruise of this project, RR2004. Bottle data were collected from CTD casts with tripped Niskin bottles on the CTD Rosette. Trace-metal-clean casts were performed using Niskin-X bottles suspended on Kevlar line and a trace-metal-clean block. The data reported herein fall into several categories: A) CTD-associated variables [temperature, salinity, density, dissolved oxygen and oxygen solubility, potential temperature, chlorophyll fluorescence, beam transmissivity, light], B) bottle salinity measurements using a salinometer, C) oxygen titrations and nutrient analyses performed aboard ship, biogeochemical/biological variables, and D) DIC chemistry variables. Regarding the specific data, we first report CTD variables (conductivity, salinity, temperature, potential temperature, density, dissolved oxygen, sound velocity, pressure, depth, conductivity, SeaBird-probe-derived oxygen concentrations, chlorophyll fluorescence, beam transmittance (660nm; %), backscattering, CTD PAR, and surface PAR reference). Next, results from bottle samples for salinity, lab oxygen titration, and nutrient concentrations (nitrate, phosphate, silicate, nitrite, and ammonium). The following biogeochemical and biological results are presented (analyzed post-cruise): particulate organic carbon concentration (POC), particulate organic nitrogen (PON), particulate inorganic carbon (PIC), biogenic silicate (BSi), concentration of detached coccoliths (given as birefringent singlets, doublets, triplets or quadruplets, when viewed in a compound microscope with polarization optics), total coccolith concentration (the sum of singlets, doublets, triplets or quadruplets), concentration of birefringent plated coccolithophore cells, coccospheres or coccolith aggregates, planar area subtended by detached coccoliths or plated cells, concentration of extracted chlorophyll, phaeopigment and their sum (done aboard ship). There are a suite of variables from FlowCAM measurements (done aboard ship), mostly done on particles >5 micrometers (um) diameter: Particle size distribution function (PSDF) slope, standard error of that PSDF slope, Y-intercept of the PSDF, R^2 of the PDF slope, F statistic of PSDF slope, total cell concentration per mL, concentrations (in cells per mL) of small 0-4um diameter cells, 4-12um round cells, 4-12um diameter ovoid cells, dinoflagellates, ciliates, diatoms silicoflagellates, other unidentified cells, followed by percent of total cell concentrations, and carbon biomass (using equations of Menden Deuer and Lessard) for the same cell categories. Carbon fixation rates were performed aboard the ship and samples were analyzed aboard ship. The data are presented here for: ratio of calcification/photosynthesis, photosynthesis, calcification, standard deviation of photosynthesis and calcification measurements, chlorophyll concentration within incubation bottles, chlorophyll normalized photosynthesis and calcification. Corrected salinity (based on bottle salinity), corrected SeaBird oxygen values based on lab oxygen titrations, dissolved inorganic carbon (DIC) concentrations, and total alkalinity. Finally, photophysiological measurements were made aboard ship and the photophysiological coefficients are presented for (a) average bulk PAM (pulse amplitude modulation) fluorimetry results and (b) average PAM microscopy results made on individual coccolithophores, dinoflagellates, and diatoms.本数据集隶属于美国国家科学基金会（National Science Foundation, NSF）资助的项目“协作研究：南大洋亚南极模态水的生物地球化学与物理调控过程”。具体而言，这些数据为“托马斯·G·汤普森号”（R/V Thomas G. Thompson）科考船TN376航次的离散采水器数据，该航次于2020年1月22日从南非开普敦起航前往南大洋，并于2020年3月3日返回毛里求斯。本项目旨在阐明南大洋亚极锋处形成的亚南极模态水的调控过程。 航次规划从开普敦向东南航行，首个预备站位位于南纬38°35′、东经024°，但因恶劣天气最终取消。起航两天后，船舶3号主发动机与发电机之间的耦合器发生故障，导致船舶仅剩1台主发动机及配套发电机，外加2台小型发动机/发电机满足全部电力需求。由于冗余系统失效，团队不得不缩短航次计划，以确保船舶始终处于南非德班数百海里范围内，以便在找到替换耦合器后能尽快入坞维修。此外，团队不得不放弃本次航次原定的经向断面观测任务：一方面，前往船厂、维修及返回下一个站位将占用超过一周的采样窗口期；另一方面，船舶靠近德班且远离克罗泽群岛，无法在大学海洋实验室船队（University-National Oceanographic Laboratory System, UNOLS）的船期限制内完成经向断面观测并按时抵达毛里求斯。后续团队将该经向断面观测任务调整至本项目的第二次航次RR2004中执行。 采水数据通过温盐深仪（Conductivity, Temperature, Depth, CTD）布放的启闭式尼斯金采水器（Niskin bottle）采集获得。痕量金属洁净采样则使用悬挂于凯夫拉（Kevlar）绳上的Niskin-X采水器及痕量金属洁净采样架完成。本报告所收录的数据分为以下几类：A) 与CTD相关的变量[温度、盐度、密度、溶解氧及氧溶解度、位温、叶绿素荧光、光束透射率、光照强度]；B) 利用盐度计完成的采水样盐度测量；C) 船上开展的氧气滴定与营养盐分析、生物地球化学/生物学变量；D) 溶解无机碳（Dissolved Inorganic Carbon, DIC）化学变量。 关于具体数据，首先报告CTD变量：电导率、盐度、温度、位温、密度、溶解氧、声速、压力、深度、电导率、海鸟（SeaBird）探针测得的氧浓度、叶绿素荧光、光束透射率（660nm；%）、后向散射、CTD光合有效辐射（Photosynthetically Active Radiation, PAR）以及表层PAR参考值。其次为采水样的盐度、实验室氧气滴定及营养盐浓度（硝酸盐、磷酸盐、硅酸盐、亚硝酸盐与铵盐）测试结果。随后为航次后分析得到的生物地球化学与生物学结果：颗粒有机碳（Particulate Organic Carbon, POC）浓度、颗粒有机氮（Particulate Organic Nitrogen, PON）、颗粒无机碳（Particulate Inorganic Carbon, PIC）、生物成因硅酸盐（Biogenic Silicate, BSi）、脱离的颗石藻颗石浓度（在偏光光学复合显微镜下观测时，以单、双、三或四折射单颗石计数）、总颗石浓度（单、双、三、四折射单颗石的总和）、带壳颗石藻细胞、球石囊或颗石聚集体浓度、脱离颗石或带壳细胞所占的平面面积、提取的叶绿素、脱镁叶绿素及其总和的浓度（船上现场完成分析）。另有一套基于流式细胞影像仪（FlowCAM）的测量变量（船上现场完成），主要针对直径大于5微米（μm）的颗粒：颗粒尺寸分布函数（PSDF）斜率、该斜率的标准误差、PSDF的Y轴截距、PSDF斜率的决定系数R²、PSDF斜率的F统计量、每毫升总细胞浓度、不同粒径/类别的细胞浓度（单位：cells/mL）：0-4μm小型细胞、4-12μm圆形细胞、4-12μm卵圆形细胞、甲藻、纤毛虫、硅藻、硅鞭藻及其他未识别细胞，随后为各类细胞占总细胞浓度的百分比，以及对应细胞类别的碳生物量（采用Menden Deuer与Lessard的计算公式）。船上开展了固碳速率实验并完成现场分析，此处公布的相关数据包括：钙化/光合作用比率、光合作用速率、钙化速率、光合作用与钙化测量的标准差、培养瓶内叶绿素浓度、归一化至叶绿素的光合作用与钙化速率。此外还有校正后的盐度（基于采水样盐度）、基于实验室氧气滴定结果校正的海鸟探针氧值、溶解无机碳（DIC）浓度及总碱度。最后为船上开展的光生理测量结果，公布的光生理系数包括：(a) 整体脉冲振幅调制（Pulse Amplitude Modulation, PAM）荧光法的平均测量结果，以及(b) 针对单个颗石藻、甲藻与硅藻的PAM显微成像平均测量结果。