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. Show less..