M. R. N. Moore, S. E. Tank, M. R. Kurek, M. Taskovic, A. M. McKenna, J. L. J. Smith, S. V. Kokelj, R. G. M. Spencer
{"title":"Ultrahigh resolution dissolved organic matter characterization reveals distinct permafrost characteristics on the Peel Plateau, Canada","authors":"M. R. N. Moore, S. E. Tank, M. R. Kurek, M. Taskovic, A. M. McKenna, J. L. J. Smith, S. V. Kokelj, R. G. M. Spencer","doi":"10.1007/s10533-023-01101-3","DOIUrl":null,"url":null,"abstract":"<div><p>The Arctic is warming at a rate twice that of other global ecosystems and changing climate conditions in the Arctic are mobilizing long frozen permafrost stores of organic carbon. In ice-rich regions, permafrost thaw on sloping terrain can cause land subsidence, and the development of thaw-driven mass wasting. The Peel Plateau, Northwest Territories, Canada has extensive thaw-driven landslides called retrogressive thaw slumps that are exposing early Holocene age paleo-thaw layers and Pleistocene age glaciogenic material deposited by the Laurentide Ice Sheet. This study aimed to see if unique retrogressive thaw slump derived permafrost inputs could be readily observed in streams across six diverse thermokarst features via optical and ultrahigh-resolution mass spectrometry. Aquatic samples from water draining thermokarst slump features, and downstream of thermokarst inputs exhibited higher dissolved organic carbon concentrations and lower aromaticity as evidenced by optical parameters (e.g. declining SUVA<sub>254</sub>, increasing <i>S</i><sub>275-295</sub>) and FT-ICR MS metrics (e.g. lower AI<sub>mod</sub> and nominal oxidation state of carbon) versus upstream of thermokarst impacts. Increases in the relative abundances of assigned heteroatomic molecular formulae (e.g. CHON, CHOS, CHONS) were also greater within and downstream of thermokarst features. The unique molecular formulae present in permafrost thermokarst inputs were determined (<i>n</i> = 1844) and subsequently tracked downstream. These permafrost marker formulae were enriched in aliphatics and H/C, as well as heteroatoms and exhibited low aromaticity. A portion of the unique molecular fingerprint persisted downstream, highlighting the potential to not only assess thermokarst inputs but also to follow these inputs and their fate downstream throughout the aquatic network.</p></div>","PeriodicalId":8901,"journal":{"name":"Biogeochemistry","volume":"167 2","pages":"99 - 117"},"PeriodicalIF":3.9000,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biogeochemistry","FirstCategoryId":"93","ListUrlMain":"https://link.springer.com/article/10.1007/s10533-023-01101-3","RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
The Arctic is warming at a rate twice that of other global ecosystems and changing climate conditions in the Arctic are mobilizing long frozen permafrost stores of organic carbon. In ice-rich regions, permafrost thaw on sloping terrain can cause land subsidence, and the development of thaw-driven mass wasting. The Peel Plateau, Northwest Territories, Canada has extensive thaw-driven landslides called retrogressive thaw slumps that are exposing early Holocene age paleo-thaw layers and Pleistocene age glaciogenic material deposited by the Laurentide Ice Sheet. This study aimed to see if unique retrogressive thaw slump derived permafrost inputs could be readily observed in streams across six diverse thermokarst features via optical and ultrahigh-resolution mass spectrometry. Aquatic samples from water draining thermokarst slump features, and downstream of thermokarst inputs exhibited higher dissolved organic carbon concentrations and lower aromaticity as evidenced by optical parameters (e.g. declining SUVA254, increasing S275-295) and FT-ICR MS metrics (e.g. lower AImod and nominal oxidation state of carbon) versus upstream of thermokarst impacts. Increases in the relative abundances of assigned heteroatomic molecular formulae (e.g. CHON, CHOS, CHONS) were also greater within and downstream of thermokarst features. The unique molecular formulae present in permafrost thermokarst inputs were determined (n = 1844) and subsequently tracked downstream. These permafrost marker formulae were enriched in aliphatics and H/C, as well as heteroatoms and exhibited low aromaticity. A portion of the unique molecular fingerprint persisted downstream, highlighting the potential to not only assess thermokarst inputs but also to follow these inputs and their fate downstream throughout the aquatic network.
期刊介绍:
Biogeochemistry publishes original and synthetic papers dealing with biotic controls on the chemistry of the environment, or with the geochemical control of the structure and function of ecosystems. Cycles are considered, either of individual elements or of specific classes of natural or anthropogenic compounds in ecosystems. Particular emphasis is given to coupled interactions of element cycles. The journal spans from the molecular to global scales to elucidate the mechanisms driving patterns in biogeochemical cycles through space and time. Studies on both natural and artificial ecosystems are published when they contribute to a general understanding of biogeochemistry.