202 / 2025-04-14 21:17:16

Nitrogen-fixing cyanobacteria alleviate nitrogen limitation in the ecological succession of proglacial areas in the Arctic

Heterocyst glycolipids,Biomarkers,Glaciers retreat,Nitrogen limitation,cyanobacteria

Theme 4: Microbial and Biogeochemical Evolution through Time > Session 4e: Microbial Lipid Biomarkers and Their Isotopes in Environment, Biology, and Evolution

With the intensification of global warming, the retreat rate of glaciers in high-latitude regions, especially the Arctic, far exceeds the global average. The areas exposed by retreating glaciers are ideal for studying primary ecological succession. The rocks and glacial till exposed by the retreat of glaciers provide an oligotrophic substrate for the formation of new soils. During the primary succession of ecosystems and soil formation, nitrogen-fixing cyanobacteria in microbial communities play a key role in the nitrogen-limited stage of the soil, promoting the continued rapid prosperity of the ecosystem. In this study, a retreat chronosequence was collected from the proglacial area of the Midtre Lovénbreen glacier in the Svalbard of the Arctic. Heterocyst glycolipids, n-alkanes, and sterols were quantified to explore the gradual development of the ecosystem. Amino sugars and lignin phenols were used to evaluate the contributions of microorganisms and plants to soil organic carbon. The results show that during the primary ecological succession, there is a clear nitrogen limitation due to insufficient environmental nitrogen supply. However, nitrogen-fixing cyanobacteria effectively alleviate this limitation through nitrogen fixation, thereby enabling the ecosystem to enter a stage of rapid prosperity. This study reveals the dynamic processes of carbon and nitrogen cycling in proglacial soils, as well as the key role of microbial colonization in ecological succession, providing important evidence for a deeper understanding of the response mechanisms of high-latitude ecosystems to climate change and their carbon sequestration capacity.