Flux data of total mass, particulate organic carbon, and zooplankton fecal pellet of time-series sediment trap samples at the mooring TJ-A1B in the northern South China Sea

This dataset includes the total mass flux (TMF, mg m-2 d-1), particulate organic carbon (POC) content (%), POC flux (mg C m-2 d-1), fecal pellet numerical flux (pellets m-2 d-1), and fecal pellet carbon (FPC) flux (mg C m-2 d-1) of time-series sediment trap samples at 500 m and 1970 m water depths of the mooring TJ-A1B in the northern South China Sea from May 2021 to May 2022. A total of 42 samples were obtained (21 samples from each water depth) for this dataset. TMF of sediment trap samples was derived when the dry weight (mg) was divided by the collecting area (0.5 m2) and collecting time (18 days). POC content of sediment trap samples was measured by a Cario EL Cube elemental analyzer at the Third Institute of Oceanography, Ministry of Natural Resources, with a precision of better than ±0.02% (SD, 1σ; n = 2). POC flux was calculated by the product of the TMF and POC content. Zooplankton fecal pellets in the sinking particles were observed under a Zeiss Stemi 508 stereomicroscope coupled to a Zeiss Axiocam 305 digital camera at the State Key Laboratory of Marine Geology, Tongji University. Fecal pellets were identified, counted, and measured according to four shapes: ellipsoidal, cylindrical, spherical, and amorphous, and each shape was counted and measured separately using the Fiji software. The biovolumes of the first three fecal pellet shapes were calculated from the formulas for an ellipsoid, cylinder, and sphere, while the biovolume of amorphous fecal pellets was estimated through best-fit ellipsoid calculations. The biovolume-carbon content conversion factor used is 0.036 mg C mm-3 for all pellets. Fecal pellet numerical and carbon fluxes were obtained when the pellet number and carbon content were divided by the collecting area (0.5 m2) and collecting time (18 days).

本数据集涵盖2021年5月至2022年5月期间，南海北部TJ-A1B锚系（mooring TJ-A1B）500米与1970米水深处采集的时间序列沉积物捕获器（sediment trap）样品的多项参数，包括总质量通量（total mass flux, TMF, mg m⁻² d⁻¹）、颗粒有机碳（particulate organic carbon, POC）占比（%）、POC通量（mg C m⁻² d⁻¹）、粪球粒数值通量（pellets m⁻² d⁻¹）以及粪球粒碳（fecal pellet carbon, FPC）通量（mg C m⁻² d⁻¹）。本数据集共获取42个样品，两个水深各21个。沉积物捕获器样品的总质量通量通过干重（mg）除以采集面积（0.5 m²）与采集时长（18天）计算得到。沉积物捕获器样品的颗粒有机碳占比由自然资源部第三海洋研究所的Cario EL Cube元素分析仪测定，测定精度优于±0.02%（标准偏差SD，1σ；n=2）。POC通量通过总质量通量与POC占比的乘积计算得出。沉降颗粒中的浮游动物粪球粒由同济大学海洋地质国家重点实验室的Zeiss Stemi 508体式显微镜搭配Zeiss Axiocam 305数码相机完成观测。粪球粒按照椭球形、圆柱形、球形与无定形四种形态开展识别、计数与尺寸测量，并通过Fiji软件分别对每种形态的粪球粒进行独立计数与测算。前三种形态粪球粒的生物体积分别通过椭球体、圆柱体和球体的体积公式计算，无定形粪球粒的生物体积则通过最优拟合椭球体法估算。所有粪球粒的生物体积-碳含量转换系数统一设为0.036 mg C mm⁻³。粪球粒数值通量与碳通量通过粪球粒数量及碳含量分别除以采集面积（0.5 m²）与采集时长（18天）得到。