Description: Fieldwork was conducted in July 2022 in the coastal waters around Herschel Island - Qikiqtaruk, Canada. Seven sampling days were carried out in two consecutive weeks. Two transects were sampled repeatedly: one transect was directly affected by the discharge of a retrogressive thaw slump, while the other transect was located in front of a permafrost cliff coast. For both transects, the targeted sampling stations had the following distances from the shore: 10 m, 50 m, 100 m, 500 m, and 1000 m. These targeted stations could not always be sampled precisely due to the weather conditions, which explains the deviations in the coordinates. Salinity, electrical conductivity, water temperature, and water depth were determined with a CTD CastAway. At least two water samples were taken per sampling station per day. For stations with water depth 〉 5 m, an additional sample was taken at the depth of the thermocline (based on previous CTD measurements). Seawater was sampled using a UWITEC water sampler (USB 50050). Turbidity was measured once per sample using a HACH 2100Q turbidity meter. To perform the turbidity analysis, a representative subsample of 10 ml was taken directly from the UWITEC water sampler into a pre-rinsed glass vial. Depending on this turbidity measurement, the amount of water required for processing in the field laboratory was determined for each measuring station and depth. For each sample, 1000 to 3250 ml of seawater was transferred into Nalgene plastic bottles for transport to the field laboratory. The seawater was filtered through precombusted 0.7 µm GF/F filters using Nalgene plastic filter units. From the filtrate, 20 ml were collected for dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) measurements and acidified with 30% HCl (suprapur). All filters and DOC bottles were kept dark and cool during storage and transport to the Alfred Wegener Institute in Potsdam, Germany. DOC and TDN were measured using a Shimadzu TOC-L with TNM-L module in Potsdam. Filters were weighed after air drying at the field site and additional 48 h at 50 °C in the drying oven in Potsdam to derive SPM concentrations. Subsampling of the filters took place at the Vrije Universiteit Amsterdam, The Netherlands. Subsamples were punched out of the filters and placed in precombusted silver capsules. To remove inorganic carbon, the silver capsules were fumigated in a desiccator with 37% HCl at 60 °C for 72 h. They were then dried over NaOH at 60 °C for 48 h to neutralize the HCl. The silver capsules were then sealed in tin and analyzed for particulate organic carbon (POC), total nitrogen (TN), δ13C and δ15N using an elemental analyzer isotope mass spectrometer (EA-IRMS) at the University of California Stable Isotope Facility (Davis, USA).