We used metagenomics and metatranscriptomics, to analyze for the first time the rising plumes and plumes of three non-ridge volcanoes (Niua South, Niua North and Niuatahi) and one spreading-ridge volcano (Northeast Lau Spreading Centre-Maka) in the Tonga Arc. The plumes of Niuatahi and Maka were dominated by two species of Alcanivorax affiliating to Alcanivorax DG881 and Alcanivorax venustensis.