Flow cytometry dataset from CTD casts showing the abundance of microorganisms (smaller than 20 µm) during the Arctic MOSAiC expedition

• Main Authors: Müller, Oliver, Fong, Allison A, Snoeijs-Leijonmalm, Pauline, Creamean, Jessie, Olsen, Lasse Mørk, Eggers, Lena, Grosse, Julia, Hoppe, Clara Jule Marie, Torstensson, Anders, Heitman, Laura, Balmonte, John Paul, Chamberlain, Emelia, Dietrich, Ulrike, Larsen, Aud, Petelenz, Elzbieta, Tsagaraki, Tatiana M, Mayers, Kyle, Langvad, Maria, Granskog, Mats A, Bratbak, Gunnar
• Format: Dataset
• Language: English
• Published: PANGAEA 2023
• Subjects: Acoustic focusing cytometer; Thermo Fisher; Attune NxT [20 mW 488 nm (blue) laser]; Activity description; Arctic; Arctic Ocean; Cast number; Collector; CTD/Rosette; CTD-RO; DATE/TIME; Depth; bathymetric; water; Device type; Event label; Feature; flow cytometry; Flow cytometry system; Becton Dickinson; FACSCalibur; HAVOC; Heterotrophic nanophytoplankton; Heterotrophic prokaryotes; large; medium; very large; Heterotrophic prokaryotes with relatively high nucleic acid; Heterotrophic prokaryotes with relatively low nucleic acid; LATITUDE; Leg Number; LONGITUDE; microbial abundance; MOSAiC; MOSAiC_ECO; MOSAiC20192020; MOSAiC expedition; Multidisciplinary drifting Observatory for the Study of Arctic Climate; Orange and red fluorescing nanophytoplankton; Orange and red fluorescing picophytoplankton; Orange fluorescing prokaryote picophytoplankton; Polarstern; PS122/1; PS122/1_10-44; PS122/1_7-49; PS122/1_8-46; Phytoplankton
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.963430; https://doi.org/10.1594/PANGAEA.963430

This dataset gives an overview of the abundance of microorganisms (smaller than 20 µm) enumerated using flow cytometry (FCM) during the Multidisciplinary drifting observatory for the study of Arctic Climate (MOSAiC) sampled from ship-based and on-ice CTD rosettes during leg 1, 2, 3, 4 and 5 (November 2019 – September 2020). Additional expedition and sampling details can be found in the ECO-overview paper (Fong et al., to be submitted to Elementa). We thank all persons involved in the expedition of the Research Vessel Polarstern during MOSAiC in 2019-2020 (AWI_PS122_00) as listed in Nixdorf et al. (2021). Flow cytometry (FCM) is a fast, high-throughput method to enumerate the abundance of microorganism (smaller than 20 µm). FCM uses the hydrodynamic focusing of a laminar flow to separate and line up microscopic particles. When particles pass a laser beam, the generated light scattering can be used to estimate their cell size, obtain information about cell granularity and surface characteristics and determine fluorescence from inherent pigments or applied stains, such as DNA binding ones. Photosynthetic microorganisms have auto-fluorescent pigments, such as chlorophylls which in combination with the light scattering properties (cell size) or surface properties, can be used to group them into clusters of similar or identical organism types. Heterotrophic microorganisms, including archaea, bacteria and heterotrophic nanoflagellates, and virus do not have fluorescent pigments and require staining, for example using SYBR Green to stain Nucleic Acids (DNA/RNA) in order to distinguish these cells from other organic and inorganic particles in the sample. Samples for flow cytometric analysis were taken in triplicates or quadruplicates of 1.8 mL of sample water and fixed with 36 μL 25 % glutaraldehyde (0.5 % final concentration) at 4 °C in the dark for approximately 2 hours, then flash frozen in liquid nitrogen and stored at -80 °C until analysis. The abundance of pico- and nano-sized phytoplankton and heterotrophic ...