Prokaryotic plankton respiration, growth and abundance in the Arctic Ocean 2021

The dataset consists of results from measurements of prokaryotic (Bacteria and Archaea) plankton respiration, growth, and abundance in the Arctic Ocean surface (0-500 m) in 2021. Data was collected during the Synoptic Arctic Survey expedition with the Swedish research icebreaker Oden between July 25 and September 20, 2021. Samples were collected primarily with Niskin-bottles on a rosette-sampler equipped with a CTD probe. Some samples were also taken in the boundary layer between ice and seawater with a Ruttner sampler after a hole to the water surface was drilled. Process speeds were measured on board within an hour of sampling in a cool laboratory with a temperature of 7°C. Plankton respiration was measured by oxygen optodes in eight simultaneous samples incubated at in situ temperature. For the PROMAC project, all samples were pre-filtered with 1.2 μm filters to specifically measure prokaryotic respiration. Growth of the prokaryotic community was measured by uptake of the DNA base thymidine labeled with tritium incubated at in situ temperature. The presence of prokaryotes was measured by epifluorescence microscopy after labeling with the dye acridine orange. Cell morphology and interactions were also studied via scanning electron microscopy in samples preserved with glutaraldehyde. In the filtered samples, the presence of different prokaryotic taxa was determined by sequencing the 16S RNA gene. In addition, expression of genes from isolated mRNA was measured. For metagenomics and transcriptomics from unfiltered samples, please refer to the OMICS project from the same expedition. The main projects (“SASIce24h” and “SAS”) aim to contribute knowledge about prokaryotic plankton respiration, growth rate and total biomass to better understand the turnover of carbon in the Arctic Ocean and its regulation. The results from the expedition will also provide a basis for comparison with similar studies in the future to follow climate change. The spatial coverage will increase the understanding of how processes vary in different parts of the ocean. Simultaneous measurements in other parts of the Arctic Ocean by other countries will contribute to a more comprehensive picture. The “PROMAC” project studies the maintenance respiration of prokaryotic plankton and what activities are included there. The temperature sensitivity of plankton respiration is investigated in the “RespirationQ10”-project. Determination of the conversion factor from thymidine uptake to cell growth is carried out in the subproject "TCF". Whether enough of the trace element thymidine was added was investigated in the sub-project ”Isotope dilution”. First results will be published during 2024.本数据集包含2021年北冰洋表层（0-500米）原核生物（细菌域与古菌域）浮游生物的呼吸作用、生长状况与丰度的测量结果。数据采集于2021年7月25日至9月20日期间，搭载瑞典破冰科考船“奥登号（Oden）”开展的“北极同步调查（Synoptic Arctic Survey）”科考航次。 样本主要通过搭载CTD探头（CTD probe）的多联采水器架（rosette-sampler）上的尼斯金采水器（Niskin-bottles）采集；部分样本则是在钻开海面冰孔后，采用拉特纳采水器（Ruttner sampler）采集于冰-海水界面边界层中。 样品采集后1小时内，于科考船搭载的温度为7℃的低温实验室中完成相关过程速率的测定。浮游生物呼吸作用采用氧气光学传感器（oxygen optodes）进行测定，共设置8组平行样本，在原位温度下培养。针对PROMAC项目，所有样本均使用1.2μm滤膜进行预过滤，以特异性测定原核生物的呼吸作用。原核生物群落的生长状况，通过测定在原位温度下培养的、氚（tritium）标记的DNA碱基胸苷（thymidine）的摄取量来量化。原核生物的丰度通过吖啶橙（acridine orange）染色后，采用落射荧光显微镜（epifluorescence microscopy）计数测定。经戊二醛（glutaraldehyde）固定的样本，还通过扫描电子显微镜（scanning electron microscopy）对细胞形态与相互作用进行了观测研究。经过滤后的样本中，不同原核生物类群的组成通过16S核糖体RNA（16S RNA）基因测序进行鉴定。此外，还对提取的mRNA的基因表达水平进行了测定。如需获取未过滤样本的宏基因组学（metagenomics）与转录组学（transcriptomics）相关数据，请参阅本次航次的OMICS项目数据集。 本数据集依托的核心项目为“SASIce24h”与“SAS”，旨在获取北极海洋原核浮游生物的呼吸作用、生长速率与总生物量相关数据，以深化对北冰洋碳循环过程及其调控机制的理解。本次航次的测定结果，还可为未来开展的气候变化相关同类研究提供对比基准。本次调查的空间覆盖范围，将有助于阐明海洋不同区域的原核浮游生物过程差异。其他国家在北极洋域同期开展的同类测量工作，将助力构建更为全面的北极海洋生态研究图景。“PROMAC”项目聚焦原核浮游生物的维持性呼吸作用及其包含的生理活动类型。“RespirationQ10”项目则针对浮游生物呼吸作用的温度敏感性展开研究。子项目“TCF”负责测定胸苷摄取量与细胞生长之间的转换系数。子项目“同位素稀释（Isotope dilution）”则探究了添加的痕量元素胸苷是否足量。该数据集的初步研究成果将于2024年正式发表。