Video Plankton Recorder data from R/V Columbus Iselin, R/V Endeavor cruises CI9407, EN259, and EN262 in the Gulf of Maine and Georges Bank from 1994-1995 (GB project)

<p>This dataset includes ALL the abundance values, zero and non-zero.&nbsp; The data files are very large.&nbsp; In order to map the VPR data, see the VPR_ashjian_nonzero&nbsp;[<a href=\"http://globec.whoi.edu/jg/serv/globec/gb/vpr_cashjian_nonzero.html0\" target=\"_blank\">http://globec.whoi.edu/jg/serv/globec/gb/vpr_cashjian_nonzero.html0</a>]. In the 'nonzero' dataset, values of 0 in the abund_L column (taxon abundance) have been removed.</p>

<p>For an alternate display, including both zero and non-zero data, see VPR_ashjian_alt&nbsp;[<a href=\"http://globec.whoi.edu/jg/serv/globec/gb/vpr_cashjian_read.html0\" target=\"_blank\">http://globec.whoi.edu/jg/serv/globec/gb/vpr_cashjian_read.html0</a>].</p>

<p><strong>Methodology</strong><br />
The following information was extracted from <em>C.J. Ashjian et al., Deep- Sea Research II 48(2001) 245-282 </em>. An in-depth discussion of the data and sampling methods can be found there.</p>

<p>The Video Plankton Recorder was towed at 2 m/s, collecting data from the surface to the bottom (towyo). The VPR was equipped with 2-4 cameras, temperature and conductivity probes, fluorometer and transmissometer. Environmental data was collected at 0.25 Hz (CI9407) or 0.5 Hz (EN259, EN262). Video images were recorded at 60 fields per second (fps).</p>

<p>Video tapes were analyzed for plankton abundances using a semi-automated method discussed in <em>Davis, C.S. et al., Deep-Sea Research II 43 (1996) 1946-1970</em>. In-focus images were extracted from the video tapes and identified by hand to particle type, taxon, or species. Plankton and particle observations were merged with environmental and navigational data by binning the observations for each category into the time intervals at which the environmental data were collected (again see above <em>Davis</em> citation). Concentrations were calculated utilizing the total volume (liters) imaged during that period. For less-abundant categories, usually only a single organism was observed during each time interval so that the resulting concentrations are close to presence or absence data rather than covering a range of values.</p>

本数据集包含全部丰度数值，涵盖零值与非零值。数据文件体积较大。若需绘制视频浮游生物记录仪（Video Plankton Recorder，VPR）数据的可视化映射图，可参考VPR_ashjian_nonzero数据集，链接为<http://globec.whoi.edu/jg/serv/globec/gb/vpr_cashjian_nonzero.html0>。在该“非零值”数据集中，已移除abund_L列（分类单元丰度）中的零值条目。

若需包含零值与非零值的替代可视化展示方式，可参考VPR_ashjian_alt数据集，链接为<http://globec.whoi.edu/jg/serv/globec/gb/vpr_cashjian_read.html0>。

**研究方法**
以下信息提取自*C.J. Ashjian等人，《Deep-Sea Research II》第48卷（2001年），第245-282页*。关于本数据集与采样方法的详细探讨可参阅该文献。

本研究使用的视频浮游生物记录仪（Video Plankton Recorder，VPR）以2米/秒的速度拖曳作业，采集从表层至海底的全程采样数据（towyo）。该VPR搭载2至4台相机、温度与电导率探针、荧光计及透射计。环境数据采集频率为0.25赫兹（CI9407）或0.5赫兹（EN259、EN262）。视频图像以60帧每秒（fps）的速率录制。

录像带中的浮游生物丰度分析采用*Davis, C.S.等人，《Deep-Sea Research II》第43卷（1996年），第1946-1970页*中提及的半自动化方法完成。首先从录像带中提取清晰对焦的图像，随后通过人工识别确定其颗粒类型、分类单元或物种。将浮游生物与颗粒观测数据与环境及导航数据进行整合：将各分类的观测结果按环境数据采集的时间区间进行分箱处理（详见上述*Davis*文献）。浓度计算基于该时间段内的成像总容积（升）。对于丰度较低的分类单元，通常每个时间区间内仅能观测到单个生物体，因此所得浓度数据近似为存在/不存在数据，而非覆盖一定范围的数值。