Description: This dataset contains abiotic and biotic data from sediment samples from four sites in the northwestern Weddell Sea. Data are provided for sediment pigments (chlorophyll a and phaeopigment content through fluorometry), total organic carbon (TOC), total nitrogen (TN), stable isotope values of carbon and nitrogen (δ13C, δ15N) and grain size (silt&clay 〈 32 µm, very fine sand 63–125 µm, fine sand 125–250 µm, medium sand 250–500 µm, coarse sand 500–1000 µm, larger coarse sand 〉 1000 µm). A minimum of three replicate samples (cores) were collected using a MUC10 multicorer. All sediment cores were subsampled with a 10-ml syringe (inner diameter 1 cm). Subsamples were sliced in 1-cm steps down to 5 cm depth. The same sampling and measurements as for PS 96 were carried out (see below "Related to". Prior to TOC and δ13C analysis sediment samples were acidified to eliminate inorganic carbon. Detailed methods are described in Säring et al. (2022), except for stable isotopes: Flash combustion in a Flash 2000 (Thermo) elemental analyser to a Delta V advantage (Thermo) isotope ratio masspectrometer. δ values are reported relative to atmospheric N2 (δ15N) and Vienna PeeDee Belemnite (δ13C). Reference materials for stable isotope analysis: IAEA-N1, IAEA-N2, IAEA-N3, NBS 22, IAEA-CH-3 and IAEA-CH-6; calibration material: Acetanilide (Merck). The analytical precision for both stable isotope ratios was 〈±0.2‰. Cores with the label -e (Environment) were only used to collect the above data. Environmental, fauna and benthic boundary flux data were collected from cores with the label -i (Incubation). This data table is part of studies analyzing the role of environmental parameters for meio- and macrofaunal community compositions and polychaete community distribution patterns (see "Supplement to", "Related to" and "Further details" below).