Permafrost soils store approximately twice the amount of carbon currently present in Earth’s atmosphere and are acutely impacted by climate change due to the polar amplification of increasing global temperature. Many organic-rich permafrost sediments are located on large river floodplains, where river channel migration periodically erodes and re-deposits the upper tens of meters of sediment. Channel migration exerts a first-order control on the geographic distribution of permafrost and floodplain stratigraphy and thus may affect microbial habitats. Here, to examine how river channel migration in discontinuous permafrost environments affects microbial community composition, we used amplicon sequencing of the 16S rRNA gene on sediment samples from floodplain cores and exposed riverbanks along the Koyukuk River, a large tributary of the Yukon River in west-central Alaska. Microbial communities are sensitive to permafrost thaw: communities found in deep samples thawed by the river closely resembled near-surface active layer communities in non-metric multidimensional scaling analyses but did not resemble floodplain permafrost communities at the same depth. Microbial communities also displayed lower diversity and evenness in permafrost than in both the active layer and permafrost-free point bars recently deposited by river channel migration. Taxonomic assignments based on 16S and quantitative PCR for the methyl-coenzyme M reductase functional gene demonstrated that methanogens and methanotrophs are abundant in older permafrost-bearing deposits, but not in younger, non-permafrost point bar deposits. The results suggested that river migration, which regulates the distribution of permafrost, also modulates the distribution of microbes potentially capable of producing and consuming methane on the Koyukuk River floodplain.
Douglas, Madison M., et al. "Impact of river channel lateral migration on microbial communities across a discontinuous permafrost floodplain." Applied and Environmental Microbiology, vol. 87, no. 20, Sep. 2021. https://doi.org/10.1128/aem.01339-21
Douglas, Madison M., Lingappa, Usha F., Lamb, Michael P., Rowland, Joel C., West, A. Joshua, Li, Gen, Kemeny, Preston C., Chadwick, Austin J., Piliouras, Anastasia, Schwenk, Jonathan Paul, & Fischer, Woodward W. (2021). Impact of river channel lateral migration on microbial communities across a discontinuous permafrost floodplain. Applied and Environmental Microbiology, 87(20). https://doi.org/10.1128/aem.01339-21
Douglas, Madison M., Lingappa, Usha F., Lamb, Michael P., et al., "Impact of river channel lateral migration on microbial communities across a discontinuous permafrost floodplain," Applied and Environmental Microbiology 87, no. 20 (2021), https://doi.org/10.1128/aem.01339-21
@article{osti_1814778,
author = {Douglas, Madison M. and Lingappa, Usha F. and Lamb, Michael P. and Rowland, Joel C. and West, A. Joshua and Li, Gen and Kemeny, Preston C. and Chadwick, Austin J. and Piliouras, Anastasia and Schwenk, Jonathan Paul and others},
title = {Impact of river channel lateral migration on microbial communities across a discontinuous permafrost floodplain},
annote = {Permafrost soils store approximately twice the amount of carbon currently present in Earth’s atmosphere and are acutely impacted by climate change due to the polar amplification of increasing global temperature. Many organic-rich permafrost sediments are located on large river floodplains, where river channel migration periodically erodes and re-deposits the upper tens of meters of sediment. Channel migration exerts a first-order control on the geographic distribution of permafrost and floodplain stratigraphy and thus may affect microbial habitats. Here, to examine how river channel migration in discontinuous permafrost environments affects microbial community composition, we used amplicon sequencing of the 16S rRNA gene on sediment samples from floodplain cores and exposed riverbanks along the Koyukuk River, a large tributary of the Yukon River in west-central Alaska. Microbial communities are sensitive to permafrost thaw: communities found in deep samples thawed by the river closely resembled near-surface active layer communities in non-metric multidimensional scaling analyses but did not resemble floodplain permafrost communities at the same depth. Microbial communities also displayed lower diversity and evenness in permafrost than in both the active layer and permafrost-free point bars recently deposited by river channel migration. Taxonomic assignments based on 16S and quantitative PCR for the methyl-coenzyme M reductase functional gene demonstrated that methanogens and methanotrophs are abundant in older permafrost-bearing deposits, but not in younger, non-permafrost point bar deposits. The results suggested that river migration, which regulates the distribution of permafrost, also modulates the distribution of microbes potentially capable of producing and consuming methane on the Koyukuk River floodplain.},
doi = {10.1128/aem.01339-21},
url = {https://www.osti.gov/biblio/1814778},
journal = {Applied and Environmental Microbiology},
issn = {ISSN 0099-2240},
number = {20},
volume = {87},
place = {United States},
publisher = {American Society for Microbiology},
year = {2021},
month = {09}}
Environmental System Science Data Infrastructure for a Virtual Ecosystem; Incorporating the Hydrological Controls on Carbon Cycling in Floodplain Ecosystems into Earth System Models (ESMs)https://doi.org/10.15485/1571527