UNDER EMBARGO - This dataset is part of BE/2023 sampling campagn in SW Greenland fjords (Igaliku and Tunulliarfik). The dataset reports the final concentrations (μg L⁻¹) of each detected photosynthetic pigment, used to infer phytoplankton functional groups and compare community composition across fjords with differing glacial influence and between seasons (spring–summer). For pigment analysis, seawater volumes ranging from 700 mL to 1 L were filtered onto 25-mm diameter Whatman GF/F filters and immediately stored at -80°C until further analysis. Pigments were extracted using 90% acetone and analysed by High-Performance Liquid Chromatography (HPLC) following the method of Van Heukelem and Thomas (2001). Calibration was performed using pigment standards from DHI Water and Environment (Hørsholm, Denmark). In the dataset is indicated the final consentration (μg/L) of each detected photosyntetic pigment.

UNDER EMBARGO - This dataset originates from the BE/2023 sampling campaign conducted in southwest Greenland fjords (Igaliku and Tunulliarfik) and quantifies grazing impacts by micro- and mesozooplankton on phytoplankton and heterotrophic microbial communities (including bacteria) in two fjord systems characterized by contrasting glacial regimes. Grazing and microbial growth rates were estimated using two-point dilution experiments (two-point dilution experiments), alongside experiments assessing mesozooplankton and copepod grazing on both phytoplankton and microzooplankton. Community responses were resolved using imaging flow cytometry, enabling the identification of plankton functional groups (autotrophic, mixotrophic, and heterotrophic) and size classes. The dataset also includes measurements of chlorophyll a variability determined by high-performance liquid chromatography. Overall, the dataset supports analyses of trophic interactions and grazing dynamics across the microbial food web under differing glacier-influenced environmental conditions.

UNDER EMBARGO - This dataset is part of BE/2023 sampling campagn in SW Greenland fjords (Igaliku and Tunulliarfik). Samples for DNA extraction were collected along fjord transects at several depths of the water column. The focus of the study was to determine the taxonomical composotion of bacterial community in two Arctic fjords.

UNDER EMBARGO - This dataset is part of BE/2023 sampling campagn in SW Greenland fjords (Igaliku and Tunulliarfik). Samples for DNA extraction were collected along fjord transects at several depths of the water column. The focus of the study was to determine the taxonomical composotion of protist community in two Arctic fjords.

UNDER EMBARGO - This dataset is part of BE/2023 sampling campagn in SW Greenland fjords (Igaliku and Tunulliarfik). Pelagic community was analysed using Imaging Flow Cytometry (iFCM) with an ImageStream®X Mk II. Cells were grouped into functional size classes—pico-, nano- and microplankton—according to measured cell length. Cells lacking chlorophyll autofluorescence were classified as heterotrophic or chemotrophic organisms, including heterotrophic picoplankton/bacteria (HP; ≤2 µm) and heterotrophic nanoplankton (HN; 2–20 µm). No larger heterotrophs (>20 µm) were visually detected. Autofluorescent cells were considered phototrophic, although this fraction may also include mixotrophic taxa, and comprised picophytoplankton (AP; ≤2 µm), nanophytoplankton (AN; 2–20 µm), and microphytoplankton (AMicro; 20–100 µm). To estimate the biovolume of each plankton class, the two-dimensional cell surface area measured by the IDEAS® imaging software was multiplied by the mean cell width, assuming that cell width approximates the third spatial dimension. Carbon biomass was subsequently derived from biovolume using established carbon–volume relationships. For the HP fraction, carbon content was estimated using the bacterial conversion proposed by Romanova and Sazhin (2010), where volume is expressed in µm³. Although the HP fraction may also include heterotrophic picoeukaryotes, and its biomass may therefore be partly underestimated, this conversion was applied because the fraction was assumed to be numerically dominated by bacteria. For the other protist groups, carbon biomass was derived following Menden-Deuer and Lessard (2000). Carbon values were converted from pg C cell⁻¹ to carbon biomass (µg C L⁻¹) based on cell abundance.

UNDER EMBARGO - This dataset is part of BE/2023 sampling campagn in SW Greenland fjords (Igaliku and Tunulliarfik) and includes measurements of pelagic community respiration to assess microbial metabolic activity across fjords with contrasting glacial influence and seasonal conditions. Pelagic community respiration rates were determined following Martínez-García et al. (2009): seawater samples (200 mL; n = 4 replicates) were incubated with INT (final concentration 0.8 mM). Control samples were fixed with formaldehyde (2% final concentration) prior to incubation. After incubation, samples were filtered (0.2 μm), and the reduced INT (formazan) retained on filters was extracted with 1-propanol. Formazan concentration was determined spectrophotometrically at 485 nm, subtracting non-metabolic absorbance from controls. INT reduction rates were calculated as μmol INTf L⁻¹ h⁻¹ and subsequently converted to O₂ consumption rates (μmol O₂ L⁻¹ h⁻¹) following Martínez-García et al. (2019).