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dc.contributor.authorTelford, Richard J.eng
dc.contributor.authorBirks, Harry John Betteleyeng
dc.contributor.authorSaros, Jasmine E.eng
dc.contributor.authorHazewinkel, Roderick R. O.eng
dc.contributor.authorPerren, Bianca B.eng
dc.contributor.authorSaulnier-Talbot, Émilieeng
dc.contributor.authorWolfe, Alexander P.eng
dc.PublishedPLoS ONE 5(4): e10026en
dc.description.abstractBackground Although arctic lakes have responded sensitively to 20th-century climate change, it remains uncertain how these ecological transformations compare with alpine and montane-boreal counterparts over the same interval. Furthermore, it is unclear to what degree other forcings, including atmospheric deposition of anthropogenic reactive nitrogen (Nr), have participated in recent regime shifts. Diatom-based paleolimnological syntheses offer an effective tool for retrospective assessments of past and ongoing changes in remote lake ecosystems. Methodology/Principal Findings We synthesized 52 dated sediment diatom records from lakes in western North America and west Greenland, spanning broad latitudinal and altitudinal gradients, and representing alpine (n = 15), arctic (n = 20), and forested boreal-montane (n = 17) ecosystems. Diatom compositional turnover (β-diversity) during the 20th century was estimated using Detrended Canonical Correspondence Analysis (DCCA) for each site and compared, for cores with sufficiently robust chronologies, to both the 19th century and the prior ~250 years (Little Ice Age). For both arctic and alpine lakes, β-diversity during the 20th century is significantly greater than the previous 350 years, and increases with both latitude and altitude. Because no correlation is apparent between 20th-century diatom β-diversity and any single physical or limnological parameter (including lake and catchment area, maximum depth, pH, conductivity, [NO3−], modeled Nr deposition, ambient summer and winter air temperatures, and modeled temperature trends 1948–2008), we used Principal Components Analysis (PCA) to summarize the amplitude of recent changes in relationship to lake pH, lake:catchment area ratio, modeled Nr deposition, and recent temperature trends. Conclusions/Significance The ecological responses of remote lakes to post-industrial environmental changes are complex. However, two regions reveal concentrations of sites with elevated 20th-century diatom β-diversity: the Arctic where temperatures are increasing most rapidly, and mid-latitude alpine lakes impacted by high Nr deposition rates. We predict that remote lakes will continue to shift towards new ecological states in the Anthropocene, particularly in regions where these two forcings begin to intersect geographically.en_US
dc.publisherPublic Library of Scienceen_US
dc.rightsAttribution CC BYeng
dc.titleQuantifying recent ecological changes in remote lakes of North America and Greenland using sediment diatom assemblagesen_US
dc.typePeer reviewed
dc.typeJournal article
dc.description.versionAccepted versionen_US
dc.rights.holderHobbs et al.en_US
dc.rights.holderCopyright 2010 Hobbs et al.en_US
dc.subject.nsiVDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Sedimentologi: 456nob
dc.subject.nsiVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økologi: 488nob

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