Journal ArticleDOI
Do spectrally inferred determinations of chlorophyll a reflect trends in lake trophic status
Neal Michelutti,Jules M. Blais,Brian F. Cumming,Andrew M. Paterson,Kathleen M. Rühland,Alexander P. Wolfe,John P. Smol +6 more
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In this paper, the authors evaluate how well visible reflectance spectroscopy (VRS) determinations track past trends in aquatic primary production using sediment cores from several lake systems with well-known trophic histories.Abstract:
Visible reflectance spectroscopy (VRS) has been used to reconstruct lake sediment chlorophyll a concentrations. Despite good concordance between inferred and measured chlorophyll a values, questions remain as to whether this spectral technique is tracking past changes in aquatic primary production, or simply recording a diagenetic signal. In this study, we critically evaluate how well VRS chlorophyll a determinations track past trends in aquatic primary production using sediment cores from several lake systems with well-known trophic histories. Our study sites include Arctic, boreal and prairie lakes that encompass a gradient of trophic states. In general, our spectrally inferred chlorophyll a values tracked past trends in lake trophic status consistent with historical measurements of production, or as inferred by independent proxies of primary production. We conclude that VRS chlorophyll a inferences indeed track histories of lake production trends and that this method is widely applicable as a rapid, inexpensive and non-destructive alternative to wet-chemical analyses of sediment chlorophyll a concentrations.read more
Citations
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Legacy of a half century of Athabasca oil sands development recorded by lake ecosystems
TL;DR: It is shown that polycyclic aromatic hydrocarbons within lake sediments, particularly C1-C4–alkylated PAHs, increased significantly after development of the bitumen resource began, followed by significant increases in dibenzothiophenes.
Journal ArticleDOI
Arctic Holocene proxy climate database – new approaches to assessing geochronological accuracy and encoding climate variables
Hanna S. Sundqvist,Darrell S. Kaufman,Nicholas P. McKay,Nicholas L. Balascio,Jason P. Briner,Les C. Cwynar,Hans Petter Sejrup,Heikki Seppä,Dmitry Subetto,Dmitry Subetto,Dmitry Subetto,John T. Andrews,Yarrow Axford,Jostein Bakke,Jostein Bakke,Harry John Betteley Birks,Harry John Betteley Birks,Harry John Betteley Birks,Stephen J. Brooks,A. de Vernal,Anne E. Jennings,Fredrik Charpentier Ljungqvist,Kathleen M. Rühland,Casey Saenger,John P. Smol,A. E. Viau +25 more
TL;DR: In this article, a systematic compilation of previously published Holocene proxy climate records from the Arctic is presented, including 170 sites from north of 58° N latitude where proxy time series extend back at least to 6 cal ka (all ages in this article are in calendar years before present -BP), are resolved at submillennial scale (at least one value every 400 ± 200 years) and have age models constrained by at least one age every 3000 years.
Journal ArticleDOI
Global warming triggers the loss of a key Arctic refugium
TL;DR: The rapid transformation of one of the Earth's last remaining Arctic refugia is document, a change that is being driven by global warming, exceeding the range of regional long-term variability.
Journal ArticleDOI
Recent changes in a remote Arctic lake are unique within the past 200,000 years.
Yarrow Axford,Jason P. Briner,Colin A. Cooke,Donna R. Francis,Neal Michelutti,Gifford H. Miller,John P. Smol,Elizabeth K. Thomas,Cheryl R. Wilson,Alexander P. Wolfe +9 more
TL;DR: A lake sediment sequence from the Canadian Arctic is presented that records warm periods of the past 200,000 years, including the 20th century, and provides a perspective on recent changes in the Arctic.
Journal ArticleDOI
Spectrocolorimetric interpretation of sedimentary dynamics: The new “Q7/4 diagram”
Maxime Debret,Maxime Debret,David Sebag,Marc Desmet,W. Balsam,Yoann Copard,Brice Mourier,Brice Mourier,A.S. Susperrigui,A.S. Susperrigui,Fabien Arnaud,Ilham Bentaleb,Emmanuel Chapron,Elisabeth Lallier-Vergès,Thierry Winiarski +14 more
TL;DR: The Q7/4 diagram as mentioned in this paper allows the identification of different sediment components and provides 5 distinct poles: Clayey deposits, organic rich deposits (chlorophyll a and by products), altered organic matter deposits, iron rich deposits, carbonated deposits.
References
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Tracking environmental change using lake sediments. Volume 3: Terrestrial, algal, and siliceous indicators.
John P. Smol,H. J. B. Birks +1 more
TL;DR: In this article, a closed loop approach for time-lapse seismic monitoring is used for deblended data reconstruction using a closed-loop approach based on time lapse seismic monitoring.
Journal ArticleDOI
Eutrophication and Recovery in Experimental Lakes: Implications for Lake Management
TL;DR: Combinations of phosphorus, nitrogen, and carbon were added to several small lakes in northwestern Ontario, Canada, at rates similar to those in many culturally eutrophied lakes, and the high affinity of sediments for phosphorus indicate that rapid abatement of eutphication may be expected to follow phosphorus control measures.
Journal ArticleDOI
A stable isotope (δ13C, δ15N) model for the North Water food web: implications for evaluating trophodynamics and the flow of energy and contaminants
TL;DR: The isotopic model confirmed the trophic magnification of PCB 153 in this high-Arctic food web due to a strong correlation between contaminant concentration and organism δ15N values, demonstrating the utility of combining isotopic and contaminant approaches to food-web studies.
food web: implications for evaluating trophodynamics and the flow of energy and contaminants
TL;DR: In this article, the authors used d 15 N values of food web components from particulate organic matter (POM) through polar bears (Ursus maritimus) to create a trophic-level model based on the assumptions that Calanus hyperboreus occupies TL 2.0 and there is a 2.4% enrichment in 15 N between birds and their diets, and a 3.8% enrichment for all other components.
Journal ArticleDOI
Multi-proxy studies in palaeolimnology
Hilary H. Birks,Hilary H. Birks,Hilary H. Birks,H. John B. Birks,H. John B. Birks,H. John B. Birks +5 more
TL;DR: In this paper, the importance of pollen analysis and plant macrofossil analysis in multi-proxy studies is emphasised as lake history cannot be interpreted without knowledge of catchment history.
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