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.本数据集涵盖2021年北冰洋表层（0-500米）原核浮游生物（包括细菌域Bacteria与古菌域Archaea）的呼吸作用、生长速率及丰度测量结果。数据采集于2021年7月25日至9月20日，依托瑞典科学破冰船“奥登号”执行的北极同步考察航次（Synoptic Arctic Survey）完成。 样品主要通过搭载CTD探头（CTD probe）的采水罗架上的尼斯金采水器（Niskin-bottles）采集；部分样品则在冰面钻孔后，借助拉特纳采水器（Ruttner sampler）于冰海交界层采集。 各项过程速率在采样后一小时内，于温度设定为7℃的船载冷藏实验室中完成测定。浮游生物呼吸作用通过氧气光学传感器（oxygen optodes）进行测定，设置8组平行样品于原位温度下培养。针对PROMAC项目，所有样品均预先经1.2微米滤膜（1.2 μm filters）过滤，以特异性测定原核生物呼吸作用。原核生物群落的生长速率通过氚标记的DNA碱基胸苷（thymidine）的摄取量进行测定，培养条件为原位温度。原核生物的存在情况通过吖啶橙（acridine orange）染色后，采用落射荧光显微镜（epifluorescence microscopy）观测确定。借助经戊二醛（glutaraldehyde）固定的样品，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研究。在过滤后的样品中，通过对16S RNA基因（16S RNA gene）进行测序，确定了不同原核生物类群的存在情况。此外，还对分离得到的信使RNA（mRNA）的基因表达量进行了测定。若需获取未过滤样品的宏基因组学（metagenomics）与转录组学（transcriptomics）数据，请参考本次航次中的OMICS项目。 本数据集依托的核心项目包括"SASIce24h"与"SAS"，旨在获取原核浮游生物的呼吸作用、生长速率及总生物量相关数据，以深化对北冰洋碳周转过程及其调控机制的理解。本次航次的测定结果还将为未来开展的气候变化相关同类研究提供对比基准。空间覆盖范围的扩大将提升人们对海洋不同区域过程差异的认知。其他国家在北冰洋其他区域开展的同步观测，将有助于构建更为全面的研究图景。"PROMAC"项目聚焦原核浮游生物的维持呼吸作用及其包含的生理活动；"RespirationQ10"项目则探究浮游生物呼吸作用的温度敏感性。胸苷摄取量向细胞生长速率的转换因子测定由子项目"TCF"完成；子项目"同位素稀释（Isotope dilution）"则旨在验证添加的痕量元素胸苷是否足量。本数据集的初步研究结果将于2024年正式发表。