Spring Phytoplankton Assemblages in the Southern Ocean Between Australia and Antarctica

This dataset comprises of an excel spreadsheet of data collected on the CLIVAR-SR3 cruise in November to December 2001. The spreadsheet contains plankton and carbon data.From the abstract of the referenced publication:Variations of phytoplankton assemblages were studied in November-December 2001, in surface waters of the Southern Ocean along a transect between the Sub-Antarctic Zone (SAZ) and the Seasonal Ice Zone (SIZ; 46.9-64.9 degrees S; 142-143 degrees E; CLIVAR-SR3 cruise). Two regions had characteristic but different phytoplankton assemblages. Nanoflagellates (less than 20 microns) and pico-plankton (~2 microns) occurred in similar concentrations along the transect, but were dominant in the SAZ, Sub-Antarctic Front (SAF), Polar Front Zone (PFZ) and the Inter-Polar Front Zone (IPFZ), (46.9-56.9 degrees S). Along the entire transect their average cell numbers in the upper 70 m of water column, varied from 300,000 to 1,100,000 cells per litre. Larger cells (greater than 20 microns), diatoms and dinoflagellates, were more abundant in the Antarctic Zone-South (AZ-S) and the SIZ (60.9-64.9 degrees S). In AZ-S and SIZ diatoms ranged between 270,000 and 1,200,000 cells per litre, dinoflagellates from 31,000 to 102,000 cells per litre. A diatom bloom was in progress in the AZ-S showing a peak of 1,800,000 cells per litre. Diatoms were dominated by Pseudo-nitzschia spp., Fragilariopsis spp., and Chaetoceros spp. Pseudo-nitzschia spp. outnumbered other diatoms in the AZ-S. Fragilariopsis spp. were most numerous in the SIZ. Dinoflagellates contained autotrophs (eg Prorocentrum) and heterotrophs (Gyrodinium/Gymnodinium, Protoperidinium). Diatoms and dinoflagellates contributed most to the cellular carbon: 11-25 and 17-124 micrograms of carbon per litre, respectively. Small cells dominated in the northern region characterised by the lowest N-uptake and new production of the transect. Larger diatom cells were prevalent in the southern area with higher values of N-uptake and new production. Diatom and nanoflagellate cellular carbon contents were highly correlated with one another, with primary production, and productivity related parameters. They contributed up to 75% to the total autotrophic C biomass. Diatom carbon content was significantly correlated to nitrate uptake and particle export, but not to ammonium uptake, while flagellate carbon was well correlated to ammonium uptake, but not to export. Diatoms have contributed highly to particle export along the latitudinal transect, while flagellates played a minor role in the export.This work was completed as part of ASAC project 1343 (ASAC_1343).The fields in this dataset are:Station (depth, position, date, comments)SpeciesCells per millilitrecell carbon - micrograms per litre

本数据集包含2001年11月至12月CLIVAR-SR3航次采集的Excel电子表格格式数据，该表格存储了浮游生物与碳循环相关数据。

引用文献的摘要显示：本研究于2001年11-12月间，针对CLIVAR-SR3航次在亚南极区（Sub-Antarctic Zone, SAZ）与季节冰区（Seasonal Ice Zone, SIZ；南纬46.9°-64.9°，东经142°-143°）之间的断面南大洋表层水域，开展了浮游植物群落组成变化的研究。

两个区域拥有特征各异的典型浮游植物群落组成。纳米鞭毛虫（Nanoflagellates，粒径小于20微米）与超微型浮游生物（pico-plankton，粒径约2微米）在整个断面上的丰度相近，但在南纬46.9°-56.9°的亚南极区、亚南极锋（Sub-Antarctic Front, SAF）、极锋区（Polar Front Zone, PFZ）及极间锋区（Inter-Polar Front Zone, IPFZ）占据优势地位。在整个断面的上层70米水体中，这两类浮游生物的平均细胞丰度介于30万至110万个细胞/升之间。

大型细胞（粒径大于20微米），即硅藻与甲藻，在南南极区（Antarctic Zone-South, AZ-S）与南纬60.9°-64.9°的季节冰区丰度更高。在南南极区与季节冰区，硅藻的丰度介于27万至120万个细胞/升之间，甲藻丰度则为3.1万至10.2万个细胞/升。南南极区正处于硅藻水华暴发阶段，细胞丰度峰值可达180万个细胞/升。

硅藻群落以伪菱形藻属（Pseudo-nitzschia spp.）、脆杆藻属（Fragilariopsis spp.）以及角毛藻属（Chaetoceros spp.）为优势类群。在南南极区，伪菱形藻属的细胞数量超过其他硅藻类群；脆杆藻属在季节冰区的丰度最高。甲藻类群包含自养型（如原甲藻属Prorocentrum）与异养型类群（如旋沟藻属Gyrodinium/裸甲藻属Gymnodinium以及多甲藻属Protoperidinium）。

硅藻与甲藻对细胞碳库的贡献最大，分别为11-25微克碳/升与17-124微克碳/升。小型浮游生物在断面北部区域占据优势，该区域的氮摄取速率与新生产力均为全断面最低水平；大型硅藻细胞则在南部区域更为常见，该区域的氮摄取速率与新生产力均处于较高水平。

硅藻与纳米鞭毛虫的细胞碳含量彼此之间、与初级生产力以及各类生产力相关参数均呈现显著相关性，二者合计可占总自养碳生物量的75%。硅藻碳含量与硝酸盐摄取速率及颗粒碳输出量呈显著相关，但与铵盐摄取速率无明显关联；而纳米鞭毛虫碳含量则与铵盐摄取速率相关性良好，却与颗粒输出无关。在整个纬度断面上，硅藻对颗粒碳输出的贡献显著，而纳米鞭毛虫在颗粒输出过程中仅发挥次要作用。

本研究作为ASAC项目1343（ASAC_1343）的一部分完成。

本数据集包含以下字段：
站位（水深、位置、日期、备注）
物种
每毫升细胞数
细胞碳含量——微克碳/升