Abiotic data from Billefjorden Svalbard in August 2022

Kelps act as ecosystem engineers and foundation species, providing the food web basis for Arctic coastal, rocky shore ecosystems. Arctic fjords are undergoing large climatic changes, with the consequences of glacial and terrestrial run-off on kelp holobionts largely being unknown. We compared areas being influenced by either glacial or terrestrial run-off with a control area in Billefjorden, Svalbard in August 2022. In each area, we measured water parameters of the upper 10 m, taking CTD profiles (SWiFT CTDplus Turbidity, Valeport, St Peters Quay, United Kingdom). Further, we measured the underwater light climate (RAMSES-ACC-UV/VIS radiometer, TriOS Optical Sensor, Oldenburg, Germany). In each area, the water's trace elemental composition at 0 and 5 m water depth (Agilent 8900, Agilent Technologies; Tokyo, Japan) was analysed, as well as the relative abundance of the free-living microbial community at 5 m water depth (16S; Illumina Nova platform, Shanghai Hanyu Biotech lab, Shanghai, China).