Southern Ocean Continuous Plankton Recorder Zooplankton Records

This dataset contains results from Continuous Plankton Recorder (CPR) surveys in the Southern Ocean. When the opportunity arises, zooplankton species, numbers and abundance data are recorded on a continuous basis as vessels steam through the area between Australia and Antarctica, including Heard and Macquarie Islands. Observations have been made since June 1990 and are ongoing. Obviously the observations are not continuous over the region with time.

Many of the original SO-CPR logbooks from the various voyages have also been scanned, and are available via the Australian Antarctic Data Centre's Reports Register.

Zooplankton have been identified to lowest possible taxon, usually species, and counted for each segment. For copepods, copepodites and for some species nauplii (e.g. Rhincalanus gigas) have been counted separately, and for euphausiids, naupliar, calyptopis and furcilia developmental stages are identified.

The fields in this dataset are:
Tow_number - the CPR tow number
Ship_name - the name of the ship on which the tow was conducted
Season - two-year Antarctic season based around the austral summer, e.g. '2000-01' runs from July 2000 to June 2001
Latitude - the decimal latitude of the segment sample
Longitude - the decimal longitude of the segment sample
Observation_date - UTC date and time of the segment sample in ISO8601 format (yyyy-mm-ddTHH:MMZ)
Observation_date_year - the observation date year
Observation_date_month - the observation date month
Observation_date_day - the observation date day
Observation_date_hour - the observation date hour
Observation_date_minute - the observation date minute
Observation_date_time_zone - the observation date time zone (0=UTC)
Segment_number - the individual segment number within each tow
Segment_length - the distance travelled by the CPR during this segment (nautical miles). This is the true segment length as used in the Geocoding program used to cut the silk, and to calculate positions and average environmental data for each segment. In theory, all segments are 5 nautical miles long. However, this wasn't always the case with early Aurora Australis tows, where it was assumed that each marked segment was 5 nautical miles whereas each tow had subtle variations in silk advancement, depending on the wear of the cassette or travel with or against a current. True segment length has since been recalculated. At other times, some silks have been incorrectly cut and the true length has again been recalculated. The last segment of each tow may be less than 5 nautical miles. This field can be used to standardise species counts to say 5 nautical miles or to a theoretical volume filtered by multiplying the distance travelled by aperture area (12.7 x 12.7 mm): Volume Filtered = Distance (n miles) x 1852 metres x 0.0127^2. A 5 nautical mile segment theoretically represents 1.49 m^3.

Total_abundance - total count of all zooplankton in a segment

Phytoplankton_colour_index - visual estimation of the green colour of the silk mesh. Values are 'No Colour', 'Very Pale Green', 'Pale Green', or 'Green'. This colouration is due to the green chlorophyll pigments derived from chloroplasts of intact and broken cells and small unarmoured flagellates. It may provide an indicator of phytoplankton standing stock, although in the Southern Ocean there are some diatoms that are quite common on the silks but as they have very low amounts of chlorophyll the colour doesn't register in the PCI analysis.

Fluorescence - water fluoresence measured by the vessel, averaged for the segment (arbitrary units). See Quality notes for more information.

Salinity - water salinity measured by the vessel, averaged for the segment (psu). See Quality notes for more information.

Water_temperature - water temperature measured by the vessel (degrees Celsius). See Quality notes for more information.

Photosynthetically_active_radiation - photosynthetically active radiation measured by the vessel (micro-Einsteins m-2 s-1). This is not available on some vessels but has been included as a useful parameter to help differentiate data from night and day.

The remaining fields ('Abylidae' through to 'Vibilia_sp') are zooplankton taxon names. The entries in these columns are the counts of each taxon in the segment.

本数据集包含南大洋连续浮游生物记录仪（Continuous Plankton Recorder, CPR）调查的相关结果。当航行船舶途经澳大利亚与南极洲之间的海域（包括赫德岛和麦夸里岛）时，调查人员会持续记录浮游动物的物种、数量与丰度数据。该观测工作始于1990年6月，目前仍在持续进行中。显然，该区域的观测并非随时间连续全覆盖的。

历次航行留存的大量原始SO-CPR航行日志均已完成扫描，可通过澳大利亚南极数据中心（Australian Antarctic Data Centre）的报告登记系统获取。

浮游动物已被鉴定至尽可能低的分类单元，通常至物种级别，并对每个分段进行计数。针对桡足类，其桡足幼体以及部分物种的无节幼体（如大唇角真宽水蚤*Rhincalanus gigas*）已单独计数；针对磷虾类，则已鉴定出无节幼体、帽形幼体与叉胸幼体等发育阶段。

本数据集包含以下字段：
- Tow_number：CPR拖曳编号
- Ship_name：实施拖曳作业的船舶名称
- Season：以南极夏季为基准的两年期南极季节，例如“2000-01”代表2000年7月至2001年6月
- Latitude：分段样本的十进制纬度
- Longitude：分段样本的十进制经度
- Observation_date：分段样本的UTC日期与时间，采用ISO8601格式（yyyy-mm-ddTHH:MMZ）
- Observation_date_year：观测日期的年份
- Observation_date_month：观测日期的月份
- Observation_date_day：观测日期的日
- Observation_date_hour：观测日期的小时
- Observation_date_minute：观测日期的分钟
- Observation_date_time_zone：观测日期的时区（0代表UTC）
- Segment_number：单次拖曳内的独立分段编号
- Segment_length：本分段内CPR行进的距离（海里）。该数值为地理编码程序所使用的真实分段长度，该程序用于切割滤丝、计算各分段的位置与平均环境数据。理论上所有分段长度均为5海里，但早期“南极光号”（Aurora Australis）的拖曳作业并非如此：当时假设每个标记分段为5海里，但由于滤丝盒磨损或顺流/逆流航行的影响，实际拖曳过程中滤丝推进存在细微差异，后续已重新计算真实分段长度。在其他场景中，部分滤丝曾被错误切割，因此也重新核算了真实长度。单次拖曳的最后一个分段长度可能不足5海里。该字段可用于将物种计数标准化为5海里分段的计数，或通过行进距离乘以孔径面积（12.7×12.7 mm）计算理论过滤体积：过滤体积=距离（海里）×1852米×(0.0127)²。一段5海里的分段理论过滤体积为1.49 m³。
- Total_abundance：单个分段内所有浮游动物的总计数
- Phytoplankton_colour_index：滤丝网的绿色色度目视评估值，取值为“No Colour”（无色）、“Very Pale Green”（极浅绿）、“Pale Green”（浅绿）或“Green”（绿色）。该色度源自完整与破碎细胞的叶绿体以及小型无装甲鞭毛藻所含的绿色叶绿素色素，可作为浮游植物现存量的指示指标。但在南大洋中，部分常见于滤丝上的硅藻因叶绿素含量极低，无法在色度指数分析中显现颜色信号。
- Fluorescence：船舶测量的水体荧光强度，为该分段的平均值（任意单位），详细信息参见质量说明。
- Salinity：船舶测量的水体盐度，为该分段的平均值（psu，实用盐度单位），详细信息参见质量说明。
- Water_temperature：船舶测量的水体温度（摄氏度），详细信息参见质量说明。
- Photosynthetically_active_radiation：船舶测量的光合有效辐射（微爱因斯坦·m⁻²·s⁻¹）。部分船舶未配备该测量设备，但该参数可用于区分日间与夜间观测数据，因此仍被纳入数据集。
- 剩余字段（从“Abylidae”到“Vibilia_sp”）均为浮游动物分类单元名称，对应列的数值为该分段内对应分类单元的个体计数。