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 3 stations on the West Greenlandic continental shelf (67.5-70.5 N, 56.2-56.9 W) in July 2021, project ECOTIP”

As part of the project ECOTIP, a field campaign was conducted along the West Greenlandic continental shelf in July 2021 with the research vessel Dana.

A bottom-moored short-term sediment trap array (KC Denmark type) was deployed for 18.7-24.4 hours at 3 stations: 

1) Dana_station14 on 21 July 2022,
2) Dana_station22 on 26 July 2022, and 
3) Dana_station28 on 24 July 2022. 

The downward flux of the following parameters was assessed in sediment trap cylinders (inner diameter 72 mm, KC Denmark, aspect ratio 6.25), which were deployed empty and filled themselves during deployment. The cylinders were placed at 5 sampling depths: 20, 30, 50, 90, 120 m. 
 
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 (Phaeo) (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 date of the sediment trap deployment (YYYYMMDD). Details on the sample analyses and references to additional data from the same field campaign can be found below.

The downward flux of the following parameters was assessed with sediment trap cylinders (inner diameter 72 mm, KC Denmark, aspect ratio 6.25), deployed in gimballed metal frames. The cylinders were deployed empty and filled themselves with ambient seawater during the deployment. A minor overestimation of the downward flux can therefore not be excluded. The sediment trap cylinders were deployed at 5 standard depths: 20, 30, 50, 90, and 120 m depth. 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. 
Analyses for the concentration of total chlorophyll a (Chl a, > 0.7 micrometre), Chl a > 10 micrometre, total phaeophytin (Phaeo, > 0.7 micrometre), 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 100-300 mL were filtered onto GF/F filters. In addition, one replicate of 200-1000 mL was filtered on a 10 micrometre Millipore filter (with 10 micrometre holes) 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 100-500 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.
    
The cruise report is publicly available on Zenodo (https://zenodo.org/doi/10.5281/zenodo.5913276). In addition, the following data sets are available: 1) the concentration of suspended Chl a (>0.7 and >10 micrometre) and of POC and PON in the water column is published in the NIRD research data archive (https://doi.org/10.11582/2024.00039), 2) the protist composition in the water column on GBIF (https://doi.org/10.15468/sfxd3c), and 3) the community composition of sinking protist cells on GBIF (https://doi.org/10.15468/kw3rs9).

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