Microbial community response to experimental warming in boreal peatlands

Boreal peatlands are vital for global carbon storage as limited microbial decomposition slows carbon release. However, climate change is expected to affect microbial communities and biomasses, and therefore carbon storage in peatlands. This study sampled experimentally warmed plots from two fens with differing vegetation across two years. Metabarcode sequencing and quantitative PCR (qPCR) assessed changes in microbial diversity and biomass, focusing on bacteria, fungi, and protists. qPCR was also tested as a biomass proxy and corroborated fungal-to-bacterial biomass ratios at each fen, indicating carbon sequestration potential. Experimental warming had no significant effect on microbial diversity, composition, or fungal-to-bacterial ratios, though microbial communities were more influenced by sampling year. This could be from insufficient temporal resolution to detect long-term community changes over short-term variations. Overall, the study demonstrates the importance of temporal scale in characterizing microbial trends in boreal peatlands and shows qPCR provides a reasonable biomass proxy.