Molecular marker concentrations in fjord sediments located along the transect from Skagerrak to northern Norway _Dataset

Description: This dataset contains concentrations of selected chemical geomarkers determined in recent surface sediments (0–5 cm) collected during the AREX research cruise aboard the R/V Oceania (IO PAN) in August–September 2021. Samples were taken using a Van Veen grab sampler from eight Norwegian fjords distributed along a wide latitudinal gradient (58°N–69°N) covering the continental Norwegian coast (~25,000 km of shoreline). The sampling sites included locations along the transect from the Skagerrak coast (Larviksfjorden, Østerfjorden), through other parts of the North Sea in southwestern Norway (Høgsfjorden, Selbjørnfjorden, Årebrotsfjorden), to sites situated in northern Norway on the Norwegian Sea coast (Holandsfjorden, Mistfjorden, Malangen Fjord). These fjords differ in size, bottom topography (e.g., sill depths), bedrock geology, and hydrodynamic regimes, reflecting varying intensities of Atlantic water inflows and freshwater input. The dataset provides concentrations of the following groups of biomarkers: photosynthetic pigments, alkenones, polar steroids, n-alkanes, saturated cyclic hydrocarbons (hopanes and steranes), polycyclic aromatic hydrocarbons (PAHs). All chemical analyses were performed at the Laboratory of Marine Chemical Markers, Institute of Oceanology, Polish Academy of Sciences (Sopot, Poland), following procedures described in: Krajewska et al. (2017, 2020, 2023), Szymczak-Żyła and Lubecki (2022), Lubecki and Szymczak-Żyła (2024). References: Krajewska, M., Szymczak-Żyła, M., Kowalewska, G., 2017. Algal pigments in Hornsund (Svalbard) sediments as biomarkers of Arctic productivity. Pol. Polar Res. 38 (4), 423–443. https://10.1515/popore-2017-0025. Krajewska, M., Szymczak- Żyła, M., Tylmann, W., Kowalewska, G., 2020. Climate change impact on primary production and phytoplankton taxonomy in Western Spitsbergen fjords based on pigments in sediments. Global Planet. Change 189, 103158. https://doi.org/10.1016/j.gloplacha.2020.103158. Krajewska, M., Lubecki, L., Szymczak-Żyła M., 2023. Sources of sedimentary organic matter in Arctic fjords: Evidence from lipid molecular markers. Cont. Shelf Res. 264, 105053. https://doi.org/10.1016/j.csr.2023.105053. Szymczak-Żyła, M., Lubecki, L., 2022. Biogenic and anthropogenic sources of sedimentary organic matter in marine coastal areas: a multi-proxy approach based on bulk and molecular markers. Mar. Chem. 239, 104069. https://doi.org/10.1016/j.marchem.2021.104069. Lubecki, L., Szymczak-Żyła, M., 2024. Application of various molecular markers for investigating petrogenic inputs in coastal systems strongly impacted by anthropogenic stressors. Mar. Pollut. Bull. 201, 116224. https://doi.org/10.1016/j.marpolbul.2024.116224. Funding: This research was funded by the National Science Centre, Poland [Grant No. 2023/49/B/ST10/03768] and the Statutory Research Programme of the Institute of Oceanology, PAN [Zadanie_II.4]. Additional information: This dataset is related to the following article which has been accepted for publication: Szymczak-Żyła M., Lubecki L., Krajewska M. The latitudinal variations in sedimentary molecular markers reveal broad-scale spatial patterns in organic matter sources and anthropogenic pressure across Norwegian fjords, NE Atlantic. Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2025.180486