Environmental conditions along the fjord gradient of Woodfjorden, Svalbard were characterized in August 2024 at a total of ten sampling station using a SWiFT CTDplus turbidity probe (Valeport, St. Peters Quay, United Kingdom; n = 3 per station) to measure water temperature (°C), absolute salinity (SA), and turbidity (NTU). The CTD was lowered through the water column at a constant speed of approximately 1 m s⁻¹. Data were averaged over 1 m depth intervals. Spectrally resolved underwater irradiance (400–700 nm) was measured using a RAMSES-ACC-UV/VIS radiometer (TriOS Optical Sensor, Oldenburg, Germany) from the water surface to the seafloor (maximum depth 10 m; n = 3 per station). Photosynthetically active radiation (PAR) was calculated by integrating irradiance across the measured wavelength range. The light attenuation coefficient (Kd) was calculated between the surface and a water depth of 3 m. The spectral peak at a depth of 3 m was defined as the wavelength exhibiting the highest transmitted irradiance through the water column.