Under-ice winter blooms mirror summer sulfur and methane oxidation at the redox transition zone of an emerged Arctic cold seep

An emerged, frozen Arctic cold seep located in Adventdalen, Svalbard (the Lagoon Pingo), was sampled as part of a seasonal study during three ice-covered periods (April 2020, March 2021, March-May 2023) as well as during summer campaigns in August 2019 and September 2020. Winter sampling targeted the ice blister and the underlying water reservoir, while summer sampling focused on groundwater discharge, pond margin sediments, oxic surface sediments, and overlying sunlit water. Microbial 16S rRNA gene amplicon sequences, metagenomes and one metatranscriptome were generated. This study aimed to investigate seasonal microbial dynamics at the Lagoon Pingo, with particular focus on under-ice microbial successions and the responses of redox-sensitive microbial communities to seasonal environmental changes.