design: This study aims to characterize the active microbial functions in deep-sea hydrothermal vent biofilm samples collected from the Arctic Mid-Ocean Ridges. Total RNA was extracted from the same environmental samples and reverse-transcribed into complementary DNA (cDNA). Libraries were prepared using Oxford Nanopore Technologies cDNA sequencing protocol and sequenced on a MinION Mk1C device to generate long-read data, enabling full-length transcript recovery and improved resolution of operon structures and isoforms. The design compares gene expression profiles and functional activity across vent sites with varying temperature and chemical gradients. This metatranscriptome is from the Aegir's vent field, original sample name GS22-107-ROV579-BS2-P.