What the study found
The study found evidence for widespread methane cycling across the Laptev Sea shelf, with the strongest signals in the outer shelf region. It also found depleted carbon isotope signals in mid-shelf sediments and a more complicated pattern near the Lena River delta.
Why the authors say this matters
The authors say the findings help reveal broader cross-shelf patterns of enhanced methane cycling in the Laptev Sea. They also suggest that sedimentary biomarkers can preserve a time-integrated signal of methane oxidation where seawater methane measurements are highly variable.
What the researchers tested
The researchers measured the carbon isotope composition (δ13C, the ratio of stable carbon isotopes) of specific C30 hopanoids, which are membrane lipids from aerobic methanotrophs, in surface sediments from 23 sites across the Laptev Sea shelf. They also used 16S-rRNA analyses to assess interpretations of the hopanoids and possible sources.
What worked and what didn't
Across the shelf, the δ13C-C30 hopenes ranged from −57.5‰ to −37.1‰ and were consistently low, indicating aerobic methane oxidation. The depleted signals were most pronounced in the outer shelf, but also appeared in the mid-shelf region. Near the Lena River delta, the signals were isotopically heavier, which the authors say may reflect lower aerobic methane oxidation, a greater relative abundance of type II methanotrophs, and isotope dilution from non-methanotrophic sources; even there, the values were still much lower than δ13C-organic carbon.
What to keep in mind
The abstract notes that seawater methane concentrations are highly variable in space and time and can be affected by storm-driven exchanges to the atmosphere. It also says biomarker interpretation near the Lena River delta is complicated by mixed sources, and no additional limitations are described in the available summary.
Key points
- Low δ13C-C30 hopenes values across 23 sediment samples indicated aerobic methane oxidation.
- The strongest methane cycling signal was reported in the outer Laptev Sea shelf.
- Depleted biomarker signals were also found in the mid-shelf region, which had been thought to have lower methane cycling.
- Near the Lena River delta, heavier isotope values may reflect mixed influences, including lower methane oxidation and isotope dilution.
- The study used surface-sediment biomarkers and 16S-rRNA analyses to assess methane cycling.
Disclosure
- Research title:
- Sediment biomarkers indicate enhanced methane cycling across the Laptev Sea
- Authors:
- Albin Eriksson, Birgit Wild, Wei-Li Hong, Henry Holmstrand, F. J. A Nascimento, Stefano Bonaglia, Denis Kosmach, Igor Semiletov, Natalia Shakhova, Örjan Gustafsson
- Institutions:
- Bolin Centre for Climate Research, Bolin Centre for Climate Research, Bolin Centre for Climate Research, Bolin Centre for Climate Research, Institute of Geosphere Dynamics, National Research Tomsk State University, National Research Tomsk State University, Östersjöcentrum, Östersjöcentrum, Sakhalin State University, Stockholm University, Stockholm University, Stockholm University, Stockholm University, Stockholm University, Stockholm University, University of Gothenburg, V.I. Il'ichev Pacific Oceanological Institute, V.I. Il'ichev Pacific Oceanological Institute
- Publication date:
- 2026-02-24
- OpenAlex record:
- View
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