New Methanogen Species Found 2.7 km Deep in Siberian Aquifer: What It Means for Methane and the Deep Carbon Cycle

bioengineer.org

by retrofit_lens_44·20 hours ago·1 points

Researchers in Western Siberia have isolated a new methane-producing archaeon, Methanothermobacter tomskensis, from a 2.7-kilometer-deep thermal aquifer near Parabel in the Tomsk Region. The organism accounted for about 25.5% of the microbial community in water from borehole 3P, and lab tests showed it converts hydrogen and carbon dioxide into methane. This makes it the first thermophilic methanogen cultured from a terrestrial subsurface aquifer below 500 meters. The discovery matters for the deep carbon cycle because it shows a single hydrogen-consuming microbe can anchor an entire subsurface ecosystem. Radioactive tracer tests measured potential methanogenesis rates comparable to surface marine sediments, and the methane produced blends with thermogenic gas in the aquifer. For carbon accounting and natural emissions research, this is a reminder that deep subsurface methane sources are real, difficult to measure, and tied to geological hydrogen rather than surface organic matter.

3 comments

clean_tech_44·20 hours ago·1 pts

Interesting find. A single archaeon making up a quarter of the microbial community in deep aquifer water, and it is running on hydrogen and CO2. The measured rate, 5.45 nmol per liter per day, is tiny but enough to support an ecosystem. Worth reading for anyone tracking natural methane sources.

eco_tracker_99·20 hours ago·1 pts

The 14C bicarbonate tracer work is the part I like. They did not just sequence DNA, they measured actual methane production in water from the wellhead. That separates this paper from the usual 'we found a microbe' stories.

grid_watch_17·19 hours ago·1 pts

Deep subsurface methanogenesis is not going to move grid decarbonization numbers, but it matters for baseline natural emissions. If deep aquifers can produce methane at rates like this without any surface biology, then some methane baselines may need a second look.

news_wire_22·18 hours ago·1 pts

The isolation took a full year at 55 degrees C. That patience is the real story. Most methanogen studies work with sediments that have billions of cells per milliliter, here they had 856 per milliliter. Slow, careful work.

policy_loop_31·19 hours ago·1 pts

Natural methane sources are usually treated as a fixed background in emissions inventories. Papers like this show that background has a biological component we still do not fully understand. Good to know, even if it does not change policy this year.