Details on the files in the data set: “Downward flux of chlorophyll a, phaeophytin, particulate organic carbon (POC), particulate organic nitrogen (PON), and the atomic ratio of POC:PON at 7 stations in East Greenlandic fjords (72.1-76.7 N, 19.6-24.6 W) in August 2022, project ECOTIP”

As part of the project ECOTIP, a field campaign was conducted along the East Greenlandic coast in August 2022 with the R/V Maria S. Merian.

A short-term sediment trap array (KC Denmark type) was deployed for 21.5-23.5 hours at 7 stations: 
1) station MSM110_10-2 on 13 August 2022 (Arden Caple Fjord),
2) station MSM110_11-4 on 14 August 2022 (Arden Caple Fjord),
3) station MSM110_12-5 on 15 August 2022 (Arden Caple Fjord),
4) station MSM110_14-4 on 17 August 2022 (Dove Bay), 
5) station MSM110_16-4 on 21 August 2022 (King Oscar Fjord), 
6) station MSM110_17-3 on 22 August 2022 (King Oscar Fjord), and 
7) station MSM110_18-2 on 23 August 2022 (King Oscar Fjord). 

The downward flux of the following parameters was assessed in sediment trap cylinders (inner diameter 72 mm, KC Denmark), which were deployed pre-filled with filtered sea water (0.7 micrometre GF/F filters) and a salinity of around 40. The cylinders were placed at 6-8 sampling depths, depending on the bottom depth of the fjord, at the standard depths 20, 30, 50, 90, 120, 200, 300, and 400 m. After recovery of the sediment trap array, the water from the trap cylinders at each sampling depth was gently transferred into a carboy, which was stored cool and in darkness until further handling. 

The collected water was analysed for the following parameters: 
1) the downward flux of total (> 0.7 micrometre) chlorophyll a (Chl a) (mg Chl a m^-2 d^-1), 
2) the downward flux of Chl a > 10 micrometre (mg Chl a > 10 micrometre m^-2 d^-1), 
3) the downward flux of total (> 0.7 micrometre) phaeophytin (mg Phaeo m^-2 d^-1), 
4) the downward flux of Phaeo > 10 micrometre (mg Phaeo > 10 micrometre m^-2 d^-1),
5) the downward flux of particulate (>0.7 micrometre) organic carbon (POC) (mg POC m^-2 d^-1), 
6) the downward flux of particulate (>0.7 micrometre) organic nitrogen (PON) (mg PON m^-2 d^-1), and 
7) the atomic ratio of PON:PON of the sinking matter. 

The data are presented here in one file per sampling station. The file title and the ID refers to the sampling station (and the activity at this station) and date of the sediment trap deployment (YYYYMMDD). References to additional data from the same field campaign can be found in the comment section below.

Analyses for the concentration of chlorophyll a (Chl a), Chl a > 10 micrometre, phaeophytin (Phaeo), Phaeo > 10 micrometre, particulate organic carbon (POC) and nitrogen (PON) were done in the following way: For total Chl a and Phaeo concentration, triplicate subsamples of 150-400 mL were filtered onto GF/F filters. In addition, one replicate of 100-950 mL was filtered on 10 micrometre Millipore filters to determine the concentration of the Chl a > 10 micrometre and Phaeo > 10 micrometre fraction. The filters were stored frozen (-20 C) until analysed with a Turner design fluorometer after 20 h extraction in the fridge in 5 mL ethanol and according to the acidification method (Holm-Hansen et al. 1965). For POC and PON, triplicated subsamples of 350-400 mL were filtered onto pre-combusted GF/F filters. The filters were stored frozen (-20 C) until analysed on an elemental analyser (440 Elemental Analyser, Exeter Analytical) after fuming with concentrated HCl to remove inorganic carbon (calcium carbonate) for 24 h.

In addition to the data presented in this file, the following data are available: 
1) cruise track with a station list (https://doi.org/10.1594/PANGAEA.953084, https://doi.org/10.1594/PANGAEA.953083), 
2) underway measurements (https://doi.org/10.1594/PANGAEA.959027), 
3) concentration of suspended chlorophyll a, phaeophytin, particulate organic carbon (POC), and particulate organic nitrogen (PON) on NIRD (https://doi.org/10.11582/2024.00038),
4) community composition of suspended protists on GBIF (https://doi.org/10.15468/k4e2a5), and 
5) community composition of sinking protist cells on GBIF (https://doi.org/10.15468/ds6q26).

Acknowledgement: Data collection was financially supported by the project ECOTIP, that received funding from the European Union Horizon 2020 research and innovation programme under grant agreement No 869383.

License: CC-BY-4.0

Contact: Camilla Svensen, Camilla.Svensen@uit.no, https://orcid.org/0000-0001-9577-3935