Abundance of microbial bacteria and phytoplankton through the water column during the AMT27 (DY084/DY085) cruise in September-November 2017.

This dataset contains depth profiles of the mean abundance of microbial bacteria, cyanobacteria and small (&lt;20 um) phytoplankton reported in cells per millilitre. Samples were measured using flow cytometry during the Atlantic Meridional Transect (AMT) cruise AMT27 (DY084/DY085). The samples were collected between September and November 2017 from 200 m to the surface, using a Seabird CTD system with a rosette of 24 Niskin bottles of 20 L volume. Samples were collected from the predawn and noon CTDs and were stored in a refrigerator and analysed within 3 hours of collection. In total 966 discrete samples were analysed and quantified using a Becton Dickinson FACSort flow cytometer which characterised and enumerated <em>Prochlorococcus</em> sp. and <em>Synechococcus</em> sp. (cyanobacteria), pico- and eukaryotic phytoplankton and microbial bacteria based on their light scattering and autofluorescence properties. Data were analysed onboard the ship during the cruise.

本数据集收录了微生物细菌、蓝细菌以及小型（<20 μm）浮游植物的平均丰度垂直剖面数据，丰度单位为细胞每毫升。样本在大西洋经向断面航次（Atlantic Meridional Transect, AMT）AMT27（编号DY084/DY085）执行期间，采用流式细胞术（flow cytometry）完成测定。
样本采集于2017年9月至11月，采样范围覆盖从200米水深至表层海水，采集设备为搭载24个20升容积尼斯金（Niskin）采水器的赛百德（Seabird）CTD系统。样本分别于黎明前和正午的CTD站位采集，采集后即刻冷藏储存，并在采样后3小时内完成分析。
总计966个离散样本采用碧迪（Becton Dickinson, BD）FACSort流式细胞仪开展分析与定量工作，该设备通过光散射与自发荧光特性，对原绿球藻属（*Prochlorococcus* sp.）、聚球藻属（*Synechococcus* sp.，蓝细菌）、超微型及真核浮游植物与微生物细菌进行表征与计数。所有数据分析工作均在科考航次期间于船上完成。