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Dillon, Peter J.; Molot, Lewis A.

doi:10.1023/a:1005731828660

Cited by 227 publications

(44 citation statements)

References 33 publications

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“…This point is seldom addressed in the current literature on long-term emissions from man-made impoundments but is critical to the proper assessment of human-induced changes to the landscape. We are unable to project empirically the relative importance of these two processes or how it will change over the long-term, but back-of-the-envelope calculations based on an average apparent mass transfer coefficient of 3.2 m yr À1 for DOC [Dillon and Molot, 1997] suggests that only 10-20% of the projected long-term C emissions from the Eastmain reservoir can be attributed to natural but displaced emissions. A process-based model is currently under development to further address such question (N. T. Roulet et al, manuscript in preparation, 2012).…”

Section: Net C Emissions Per Energy Generationmentioning

confidence: 99%

The net carbon footprint of a newly created boreal hydroelectric reservoir

Teodoru

Bastien

Bonneville

et al. 2012

Global Biogeochemical Cycles

137

102

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[1] We present here the first comprehensive assessment of the carbon (C) footprint associated with the creation of a boreal hydroelectric reservoir (Eastmain-1 in northern Québec, Canada). This is the result of a large-scale, interdisciplinary study that spanned over a 7-years period (2003)(2004)(2005)(2006)(2007)(2008)(2009)), where we quantified the major C gas (CO 2 and CH 4 ) sources and sinks of the terrestrial and aquatic components of the pre-flood landscape, and also for the reservoir following the impoundment in 2006. The pre-flood landscape was roughly neutral in terms of C, and the balance between pre-and post-flood C sources/sinks indicates that the reservoir was initially (first year post-flood in 2006) a large net source of CO 2 (2270 mg C m À2 d À1) but a much smaller source of CH 4 (0.2 mg C m À2 d À1). While net CO 2 emissions declined steeply in subsequent years (down to 835 mg C m À2 d À1 in 2009), net CH 4 emissions remained constant or increased slightly relative to pre-flood emissions. Our results also suggest that the reservoir will continue to emit carbon gas over the long-term at rates exceeding the carbon footprint of the pre-flood landscape, although the sources of C supporting these emissions have yet to be determined. Extrapolation of these empirical trends over the projected life span (100 years) of the reservoir yields integrated long-term net C emissions per energy generation well below the range of the natural-gas combined-cycle, which is considered the current industry standard.

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Section: Net C Emissions Per Energy Generationmentioning

confidence: 99%

The net carbon footprint of a newly created boreal hydroelectric reservoir

Teodoru

Bastien

Bonneville

et al. 2012

Global Biogeochemical Cycles

137

102

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“…The rates of loss were -1.9 molÁm -2 Áyear -1 for Lake 239, -1.4 molÁm -2 Áyear -1 for Lake 302S, and -0.85 molÁm -2 Áyear -1 for Lake 302N. Dillon and Molot (1997) found a mean DOC disappearance rate in five central Ontario lakes equivalent to a settling rate of 3.2 mÁyear -1 . This would yield loss rates of -0.32 to -1.6 molÁm -2 Áyear -1 , respectively, for DOC concentrations of 100-500 mmolÁL -1 .…”

Section: Resultsmentioning

confidence: 77%

“…Loss of DOC mass per unit time in Lakes 302S and 302N was less than in Lake 239 (1.4 versus 0.85 molÁm -2 Áyear -1 ) but still in the range observed by Dillon and Molot (1997). Gennings et al (2001), working on the same watersheds as Dillon and Molot (1997), found increased DOC loss at lower pH in bottle incubations of stream waters.…”

Section: Discussionmentioning

confidence: 72%

“…Gennings et al (2001), working on the same watersheds as Dillon and Molot (1997), found increased DOC loss at lower pH in bottle incubations of stream waters. This is not the case with our budget-derived rates of loss of DOC mass.…”

Section: Discussionmentioning

confidence: 93%

“…Kopacek et al (2003) reported DOC loss rates of 1.6-3.7 molÁm -2 Áyear -1 . Dillon and Molot (1997) reported DOC loss rates of 0.32-1.43 molÁm -2 Áyear -1 for seven lakes in central Ontario, Canada. Our estimate of the loss rate in Lake 239 is 1.9 molÁm -2 Áyear -1 , which according to Kopacek et al (2003) would result in ALK production of about 70 mequiv.Ám -2 Áday -1 .…”

Section: Discussionmentioning

confidence: 99%

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Separating the effects on water chemistry of climate variation and experimental manipulation in the long-term acidification and recovery of lakesThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

Hesslein

Turner

Guss

et al. 2009

Can. J. Fish. Aquat. Sci.

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Changes in climate, in particular significant changes in precipitation and evaporation and thus runoff, as well as changes in regional atmospheric deposition can affect the changes in chemical masses or concentrations in lakes. We have examined the changes in alkalinity, sulfate, and dissolved organic carbon (DOC) during a 20-year period when Lake 302S and Lake 302N at the Experimental Lakes Area (Ontario, Canada) were acidified with sulfuric, nitric, and hydrochloric acids and returned to natural pH. We used the corresponding 20-year history in Lake 239 to build chemical mass balance models for the experimental lakes. With these models, we assessed the production of alkalinity and the loss of sulfate and DOC in the context of atmospheric and watershed inputs and our experimental acid additions. Alkalinity production was greatest during the period of highest acid inputs and not detectable during pH recovery even in the early stages when pH was still low. Sulfate loss was also greatest while sulfate concentrations were increasing but counter to expectations not directly related to sulfate concentrations. Losses of the mass of DOC showed little change in response to acid additions over the 20 years, but first-order losses increased at low pH.Résumé : Les changements climatiques, en particulier les modifications significatives des précipitations et de l'évaporation et, par conséquent, du ruissellement, de même que les variations dans les dépôts atmosphériques régionaux peuvent affecter les changements des masses et des concentrations chimiques dans les lacs. Nous examinons les modifications de l'alcalinité, des sulfates et du carbone organique dissous (DOC) sur une période 20 ans durant laquelle le lac 302S et le lac 302N de la Région des lacs expérimentaux (Ontario, Canada) ont été acidifiés avec des acides sulfurique, nitrique et chlorhydrique, puis restaurés à leur pH naturel. Nous utilisons l'histoire correspondante des mêmes 20 années du lac 239 afin d'établir des modèles de bilan massique chimique pour les lacs expérimentaux. À l'aide des modèles, nous avons évalué la production d'alcalinité et la perte de sulfates et de DOC en fonction des apports de l'atmosphère et du bassin versant, ainsi que de nos additions expérimentales d'acides. La production d'alcalinité a été maximale durant la période des apports les plus importants d'acides; elle n'a pu être décelée durant le rétablissement du pH, même aux stades initiaux lorsque le pH était encore bas. La perte de sulfates était aussi maximale alors que les concentrations de sulfates augmentaient, mais contrairement aux attentes, sans relation directe avec les concentrations de sulfates. Les pertes de masse de DOC se sont peu modifiées en réaction aux additions d'acides sur la période de 20 ans, mais les pertes du premier ordre ont augmenté aux pH bas.[Traduit par la Rédaction]

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The use of mass balance investigations in the study of the biogeochemical cycle of sulfur

1997

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The use of mass balances in the investigation of the biogeochemical cycle of sulfur is reviewed for three systems: 1) upland catchments, 2) wetlands, and 3) lakes. In upland catchments, the major inputs of sulfur are via wet and dry atmospheric deposition, whereas outputs or losses occur primarily through volatilization and/or runo. In addition, sulfur may be stored in vegetation and in the forest¯oor. In wetlands (particularly peatlands), a large proportion of the sulfur inputs are derived from surface and groundwater originating in the upland system. Because of the¯uctuating water table in wetlands, they can act as a source or sink for sulfate, depending on the redox conditions. Wetlands, therefore, can signi®cantly aect input-output budgets for lakes. In most lakes, only a small portion of the sulfate input is retained, (i.e. not lost from the lake via out¯ow), indicating that there is an excess of sulfate relative to biological needs. Seepage lakes are exceptions to this generalization. Although the reactivity of the sulfate input to many lakes is low, sulfate levels, especially in regions receiving substantial atmospheric sulfur deposition, are high enough that the portion reduced results in substantial in-lake alkalinity production; in fact, in many cases, alkalinity production from sulfate reduction is greater than that resulting from not only other in-lake processes but from external sources (the catchment) as well.The importance of mass balance investigations in elucidating the biogeochemical cycling of sulfur is stressed and the need for additional studies on a whole-system basis stressed.

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Untitled

Cited by 227 publications

References 33 publications

The net carbon footprint of a newly created boreal hydroelectric reservoir

The net carbon footprint of a newly created boreal hydroelectric reservoir

Separating the effects on water chemistry of climate variation and experimental manipulation in the long-term acidification and recovery of lakesThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

The use of mass balance investigations in the study of the biogeochemical cycle of sulfur

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