1310 / 2024-09-21 00:23:53

Explosive Volcanic Eruption Reconstructed the Microbial Community Structure in the Hydrothermal Plume: 85°E, Gakkel Ridge

Gakkel ridge, Hydrothermal plume, Microbial community, Alcanivorax, Explosive volcanic eruption

Due to the limitations of subglacial investigation methods, research on the microbial community structure within hydrothermal systems of the Gakkel Ridge and its evolution in relation to geological processes is relatively lacking. During the 12th Arctic Scientific Expedition (JASMInE, 2021), hydrothermal anomalies were successfully detected in water column at CTD 01 station (85.63° N/ 85.14° E), which is provisionally named as the 85°E Hydrothermal Area. Plume samples were collected from CTD 01 station. Microbial genomic data and physicochemical characteristics of plume samples was discussed in this study.

The results showed that the dominant microbial groups primarily consisted of autotrophic sulfur-oxidizing bacteria such as Sulfurimonas and SUP05-cluster, as well as Alcanivorax known for its ability to degrade hydrocarbons. In terms of chemosynthetic carbon fixation pathways, the Calvin-Benson-Bassham cycle (CBB cycle) dominated, with the reductive tricarboxylic acid cycle (rTCA cycle) serving as an auxiliary. Compared to the microbial community compositions in the Aurora and Polaris hydrothermal plumes on the Gakkel Ridge, the 85°E hydrothermal plume showed a significant enrichment of Alcanivorax. By analyzing four metagenome-assembled genomes (MAGs) of Alcanivorax, we discovered their potential to degrade short-to-medium-chain and long-chain alkane (from C5-C17 to C32+). Combined with the results of Near-bottom optical detection, we speculate that the surge of Alcanivorax in the 85°E hydrothermal plume may be related to a recent Explosive volcanic eruption, which caused a massive release of hydrocarbons from the sediment layer.

This study provides valuable insights into understanding the microbial community structure and its dynamic changes in the 85°E hydrothermal system on the Gakkel Ridge, while also revealing potential mechanisms of interaction between microbial activities and geological events.