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dc.contributor.authorTank, Suzanne E.  Concept link
dc.contributor.authorLesack, Lance F. W.  Concept link
dc.contributor.authorGareis, Jolie A. L.  Concept link
dc.contributor.authorOsburn, Christopher L.  Concept link
dc.contributor.authorHesslein, Ray H.  Concept link
dc.date.accessioned2014-04-21T18:32:49Z
dc.date.available2014-04-21T18:32:49Z
dc.date.issued2011-07
dc.identifier.citationLimnology and Oceanography 56 (2011): 1297-1309en_US
dc.identifier.urihttps://hdl.handle.net/1912/6575
dc.descriptionAuthor Posting. © American Society of Limnology and Oceanography, 2011. This article is posted here by permission of American Society of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography 56 (2011): 1297-1309, doi:10.4319/lo.2011.56.4.1297.en_US
dc.description.abstractLakes of the Mackenzie Delta occur across a gradient that contains three clear end members: those that remain connected to river-water channels throughout the summer; those that receive only brief inputs of river water during an annual spring flood but contain dense macrophyte stands; and those that experience significant permafrost thaw along their margins. We measured dissolved organic carbon (DOC) concentration, dissolved organic matter (DOM) absorption and fluorescence, and stable isotopes of DOM, DOM precursor materials, and bacteria to elucidate the importance of river water, macrophytes, and thermokarst as DOM sources to Mackenzie Delta lakes. Despite standing stocks of macrophyte C that are sevenfold to 12-fold greater than those of total DOC, stable isotopes indicated that autochthonous sources contributed less than 15% to overall DOM in macrophyte-rich lakes. Instead, fluorescence and absorption indicated that the moderate summertime increase in DOC concentration in macrophyte-rich lakes was the result of infrequent flushing, while bacterial δ13C indicated rapid bacterial removal of autochthonous DOC from the water column. In thermokarst lakes, summertime increases in DOC concentration were substantial, and stable isotopes indicated that much of this increase came from C released as a result of thermokarst-related processes. Our results indicate that these distinct sources of DOM to neighboring arctic Delta lakes may drive between-lake differences in C cycling and energy flow. Rapidly assimilated macrophyte DOM should be an important contributor to microbial food webs in our study lakes. In contrast, the accumulation of thermokarst-origin DOM allows for a significant role in physico-chemistry but indicates a lesser contribution of this DOM to higher trophic levels.en_US
dc.description.sponsorshipThis study was supported by a Discovery Grant and Northern Research Supplement from the Natural Sciences and Engineering Research Council of Canada (NSERC) to L.F.W.L.; funds from the Science Horizons Youth Internship Program, Northern Scientific Training Program, and NSERC Northern Research Internship. Personal financial support to S.E.T. was provided by a Simon Fraser University CD Nelson Memorial Graduate Scholarship, an NSERC Canada Graduate Scholarship-Doctoral, and a Garfield Weston Award for Northern Research.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAssociation for the Sciences of Limnology and Oceanographyen_US
dc.relation.urihttps://doi.org/10.4319/lo.2011.56.4.1297
dc.titleMultiple tracers demonstrate distinct sources of dissolved organic matter to lakes of the Mackenzie Delta, western Canadian Arcticen_US
dc.typeArticleen_US
dc.identifier.doi10.4319/lo.2011.56.4.1297


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