{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,13]],"date-time":"2026-03-13T11:34:20Z","timestamp":1773401660674,"version":"3.50.1"},"reference-count":59,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2020,10,31]],"date-time":"2020-10-31T00:00:00Z","timestamp":1604102400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","award":["UIDB\/00100\/2020"],"award-info":[{"award-number":["UIDB\/00100\/2020"]}]},{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","award":["UID\/AMB\/50017\/2019"],"award-info":[{"award-number":["UID\/AMB\/50017\/2019"]}]},{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","award":["UID\/QUI\/00062\/2019"],"award-info":[{"award-number":["UID\/QUI\/00062\/2019"]}]},{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","award":["IF\/00798\/2015"],"award-info":[{"award-number":["IF\/00798\/2015"]}]},{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","award":["SFRH\/BD\/145142\/2019"],"award-info":[{"award-number":["SFRH\/BD\/145142\/2019"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Water"],"abstract":"<jats:p>Thermokarst lakes result from the thawing of ice-rich permafrost and are widespread across northern landscapes. These waters are strong emitters of methane, especially in permafrost peatland regions, where they are stained black by high concentrations of dissolved organic matter (DOM). In the present study, we aimed to structurally characterize the DOM from a set of peatland thermokarst lakes that are known to be intense sites of microbial decomposition and methane emission. Samples were collected at different depths from three thermokarst lakes in the Sasapimakwananisikw (SAS) River valley near the eastern Hudson Bay community of Kuujjuarapik\u2013Whapmagoostui (Nunavik, Canada). Samples were analyzed by spectrofluorometry, Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and elemental analysis. Fluorescence analyses indicated considerable amounts of autochthonous DOM in the surface waters of one of SAS 1A, indicating a strong bioavailability of labile DOM, and consequently a greater methanogenic potential. The three lakes differed in their chemical composition and diversity, suggesting various DOM transformations phenomena. The usefulness of complementary analytical approaches to characterize the complex mixture of DOM in permafrost peatland waters cannot be overlooked, representing a first step towards greater comprehension of the organic geochemical properties of these permafrost-derived systems.<\/jats:p>","DOI":"10.3390\/w12113059","type":"journal-article","created":{"date-parts":[[2020,10,31]],"date-time":"2020-10-31T21:39:56Z","timestamp":1604180396000},"page":"3059","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Structural Characterization of Dissolved Organic Matter in Permafrost Peatland Lakes"],"prefix":"10.3390","volume":"12","author":[{"given":"Diogo","family":"Folhas","sequence":"first","affiliation":[{"name":"Centro de Qu\u00edmica Estrutural, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"},{"name":"Department of Chemistry &amp; CESAM, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Centre d\u00b4\u00e9tudes nordiques (CEN), Universit\u00e9 Laval, Quebec City, QC G1V 0A6, Canada"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4868-4099","authenticated-orcid":false,"given":"Armando C.","family":"Duarte","sequence":"additional","affiliation":[{"name":"Department of Chemistry &amp; CESAM, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"given":"Martin","family":"Pilote","sequence":"additional","affiliation":[{"name":"Centre d\u00b4\u00e9tudes nordiques (CEN), Universit\u00e9 Laval, Quebec City, QC G1V 0A6, Canada"},{"name":"Environment and Climate Change Canada, Aquatic Contaminants Research Division, Montreal, QC H2Y 2E7, Canada"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9055-1938","authenticated-orcid":false,"given":"Warwick F.","family":"Vincent","sequence":"additional","affiliation":[{"name":"Centre d\u00b4\u00e9tudes nordiques (CEN), Universit\u00e9 Laval, Quebec City, QC G1V 0A6, Canada"},{"name":"D\u00e9partement de biologie, Universit\u00e9 Laval, Quebec City, QC G1V 0A6, Canada"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0752-0490","authenticated-orcid":false,"given":"Pedro","family":"Freitas","sequence":"additional","affiliation":[{"name":"Centre d\u00b4\u00e9tudes nordiques (CEN), Universit\u00e9 Laval, Quebec City, QC G1V 0A6, Canada"},{"name":"Centro de Estudos Geogr\u00e1ficos, Instituto de Geografia e Ordenamento do Territ\u00f3rio, Universidade de Lisboa, 1600-276 Lisboa, Portugal"}]},{"given":"Gon\u00e7alo","family":"Vieira","sequence":"additional","affiliation":[{"name":"Centro de Estudos Geogr\u00e1ficos, Instituto de Geografia e Ordenamento do Territ\u00f3rio, Universidade de Lisboa, 1600-276 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2861-8286","authenticated-orcid":false,"given":"Artur M. S.","family":"Silva","sequence":"additional","affiliation":[{"name":"Department of Chemistry &amp; QOPNA and LAQV-REQUIMTE, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1825-6528","authenticated-orcid":false,"given":"Regina M. B. O.","family":"Duarte","sequence":"additional","affiliation":[{"name":"Department of Chemistry &amp; CESAM, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5190-446X","authenticated-orcid":false,"given":"Jo\u00e3o","family":"Can\u00e1rio","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica Estrutural, Instituto Superior T\u00e9cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,10,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"221","DOI":"10.5194\/tc-6-221-2012","article-title":"Derivation and Analysis of a High-Resolution Estimate of Global Permafrost Zonation","volume":"6","author":"Gruber","year":"2012","journal-title":"Cryosphere"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"6573","DOI":"10.5194\/bg-11-6573-2014","article-title":"Estimated Stocks of Circumpolar Permafrost Carbon with Quantified Uncertainty Ranges and Identified Data Gaps","volume":"11","author":"Hugelius","year":"2014","journal-title":"Biogeosciences"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3389\/fmicb.2019.01656","article-title":"Contrasting Winter Versus Summer Microbial Communities and Metabolic Functions in a Permafrost Thaw Lake","volume":"10","author":"Vigneron","year":"2019","journal-title":"Front. 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