We present a high spatially resolved (around 300 m) data set on the chlorophyll-a concentrations of all phytoplankton (total chlorophyll-a), diatoms, haptophytes and chlorophytes various phytoplankton pigments (unit: mg/m³) estimated from particulate absorption data derived from underway AC-S measurements operated on eight R/V POLARSTERN expeditions in the Greenland Sea (North of 66.3°N to 82°N within the Atlantic Ocean) between 2015 to 2024: PS93.2, PS99.2, PS107, PS121, PS126, PS131, PS136 and PS143-2. For each data point we further provide the percentage of Atlantic Water and Polar Water and the association into the three regions: East Greenland Sea, Central Fram Strait and West Spitsbergen Current. Mind that the classification of water masses and regions is only valid for the Hausgarten area (78°N to 80°N and 7°W to 15°E). The details of the instrument set-up, the data and the methods are described in Bracher et al. (2025).
The effects of a phytoplankton bloom and photobleaching on colored dissolved organic matter (CDOM) in the sea-surface microlayer (SML) and the underlying water (ULW) were studied in a month-long mesocosm study, in May and June of 2023, at the Institute for Chemistry and Biology of the Marine Environment (ICBM) in Wilhelmshaven, Germany. The mesocosm study was conducted by the DFG research group BASS (Biogeochemical processes and Air–sea exchange in the Sea-Surface microlayer, Bibi et al., 2025) in the Sea Surface Facility (SURF) of the ICBM. The facility contains an 8 m × 1.5 m × 0.8 m large outdoor basin with a retractable roof, which was closed at night and during rain events. The basin was filled with North Sea water from the adjacent Jade Bay. Homogeneity of the ULW in the basin was achieved by constant mixing of the water column. The daily SML and ULW samples were collected alternating in the morning, about 1 h after sunrise, and in the afternoon, about 10 h after sunrise. The alternation of sampling times intended to capture a potential effect of sun-exposure duration on DOM transformations and elucidated the day and night variability of the layers. The SML was collected via glass plate sampling (Cunliffe and Wurl, 2014). The ULW was sampled via a submerged tube and a connected syringe suction system in 0.4 m depth. The removed sample volume was refilled with Jade Bay water every day. SML and ULW samples were filtered through pre-flushed 0.7 µm Whatman GF/F and 0.2 nucleopore filters into brown bottles and were stored dark and at 4 °C until measurement within weeks of the study. The brown bottles were previously combusted at 500 °C. CDOM was measured with three liquid waveguide capillary cells (LWCC, WPI, USA) of different pathlengths (10 cm, 50 cm, 250 cm) to increase the measurement sensitivity following the protocols of Röttgers et al. (2024) using a spectral detector (Avantes, Netherlands) for a total spectral range from 230 to 750 nm. A sodium chloride (NaCl) solution was used for the salinity correction. The blank-corrected absorbance spectra were then converted into Napierian absorption coefficients (Bricaud et al., 1981).