Yves T. Prairie

University of Quebec in Montreal | UQAM · Department of Biological Sciences

Aquatic sediments represent a key component for understanding CH4 dynamics and emission to the atmosphere. Once produced in the sediments, CH4 is released either by diffusion at the sediment–water interface or by bubbling out to the atmosphere when total gas pressure in the sediment exceeds local ambient pressure due to high CH4 production. Althoug...

Lentic waters are biogeochemical reactors, producing and receiving carbon (C) originally fixed by the terrestrial and aquatic biosphere, which is then buried in sediments or respired back to the atmosphere in the forms of carbon dioxide (CO2) and one of the more potent greenhouse gas (GHG) methane (CH4). Additionally, lakes serve as archives of ter...

Oxygen depletion constitutes a major threat to lake ecosystems and the services they provide. Most of the world’s lakes are located >45° N, where accelerated climate warming and elevated carbon loads might severely increase the risk of hypoxia, but this has not been systematically examined. Here analysis of 2.6 million water quality observations fr...

Tropical peatlands cycle and store large amounts of carbon in their soil and biomass1,2,3,4,5. Climate and land-use change alters greenhouse gas (GHG) fluxes of tropical peatlands, but the magnitude of these changes remains highly uncertain6,7,8,9,10,11,12,13,14,15,16,17,18,19. Here we measure net ecosystem exchanges of carbon dioxide, methane and...

The aerobic oxidation of methane (CH4) by methanotrophic bacteria (MOB) is the major sink of this highly potent greenhouse gas in freshwater environments. Yet, CH4 oxidation is one of the largest uncertain components in predicting the current and future CH4 emissions from these systems. While stable carbon isotopic mass balance is a powerful approa...

Reservoirs are essential for human populations, but their global carbon footprint is substantial (0.73–2.41 PgCO2-equivalent yr−1). Yet the temporal evolution of reservoir carbon emissions and their contribution to anthropogenic radiative forcing remains unresolved. Here we quantify the long-term historical and future evolution (1900–2060) of cumul...

Bacterial community structure can change rapidly across short spatial and temporal scales as environmental conditions vary, but the mechanisms underlying those changes are still poorly understood. Here we assessed how a lake microbial community assembles by following its reorganization from the main tributary, which, when flowing into the lake, fir...

Hypolimnetic waters and sediments of lakes and reservoirs are active sites of carbon dioxide (CO2) and methane (CH4) production and accumulation. These potent carbon greenhouse gases (C‐GHG) can be emitted to the atmosphere during water column mixing and, for hydropower reservoirs, through deep water discharge from the outflow. Deep CO2 and CH4 con...

Methanogenesis is traditionally considered as a strictly anaerobic process. Recent evidence suggests instead that the ubiquitous methane (CH4) oversaturation found in freshwater lakes is sustained, at least partially, by methanogenesis in oxic conditions. Although this paradigm shift is rapidly gaining acceptance, the magnitude and regulation of ox...

Over the last 40 years, dissolved organic carbon (DOC) has been increasing in freshwater across many boreal regions. The extent to which these long‐term changes have affected lake CO2 dynamics is unclear. We have studied the temporal trends in DOC and pressure of CO2 (pCO2) over 40 years in 15 lakes in two regions of Ontario (Canada) subjected to b...

In temperate lakes, severe oxygen depletion in the hypolimnion occurs annually in most of the lakes during summer stratification. The consumption of oxygen in the lake hypolimnion is directly related to environmental conditions. Existing models have identified mean hypolimnetic thickness (ZH), temperature and trophic status as important determinant...

Previous stable isotope and biomarker evidence has indicated that methanotrophy is an important pathway in the microbial loop of freshwater ecosystems, despite the low cell abundance of methane-oxidizing bacteria (MOB) and the low methane concentrations relative to the more abundant dissolved organic carbon (DOC). However, quantitative estimations...

Streams and rivers are known to be significant processors and emitters of carbon (C) to the atmosphere. There have been many large-scale estimates of fluvial C emissions, yet many lack quantification of temporal variability. Here, we compared the relative importance of spatial versus seasonal variability of CO2 and CH4 concentrations and fluxes, an...

Human-made reservoirs are now recognized as potentially significant sources of greenhouse gases, comparable to other anthropogenic sources, yet efforts to estimate these reservoir emissions have been hampered by the complexity of the underlying processes and a lack of coherent budgeting approaches. Here we present a unique modelling framework, the...

Collectively, reservoirs constitute a significant global source of C‐based greenhouse gases (GHGs). Yet, global estimates of reservoir carbon dioxide (CO2) and methane (CH4) emissions remain uncertain, varying more than four‐fold in recent analyses. Here we present results from a global application of the Greenhouse Gas from Reservoirs (G‐res) mode...

Headspace analysis of CO2 frequently has been used to quantify the concentration of CO2 in fresh water. According to basic chemical theory, not considering chemical equilibration of the carbonate system in the sample vials will result in a systematic error. By analysing the potential error for different types of water and experimental conditions, w...

Stable isotopic analysis is a popular method to understand the mechanisms sustaining methane (CH4) emissions in various aquatic environments. Yet, the general lack of concurrent measurements of isotopes and fluxes impedes our ability to establish a connection between the variation in the rates of CH4 emission and isotopic signature. Here, we examin...

Freshwaters are important emitters of carbon dioxide (CO2) and methane (CH4), two potent greenhouse gases (GHGs). While aquatic surface GHG fluxes have been extensively measured, there is much less information about their underlying sources. In lakes and reservoirs, surface GHG can originate from horizontal riverine flow, the hypolimnion, littoral...

Hydropower is usually considered as a low-carbon electricity source, as it does not lead to direct greenhouse gas (GHG) emissions, unlike producing electricity from fossil fuels. However, the flooding of lands following the construction of the dam generally leads to an increase in biogenic GHG emissions due to the degradation of biomass found in th...

Aim: We discuss the biogeochemistry of carbon in lakes and illustrate its main flows and transformation processes. We cover how and in what forms carbon enters lake ecosystems, how carbon is transformed within lakes, and the pathways through which it is transported out. We describe the main processes involved in the transformation of carbon between...

Freshwaters are important emitters of carbon dioxide (CO2) and methane (CH4) to the atmosphere, two potent greenhouse gases (GHG). While aquatic surface GHG fluxes have been extensively measured, there is much less information about their underlying sources. In lakes and reservoirs, surface GHG can originate from horizontal riverine flow, the hypol...

Headspace analysis of CO2 frequently has been used to quantify the concentration of CO2 in freshwater. According to basic chemical theory, not considering chemical equilibration of the carbonate system in the sample vials will result in a systematic error. In this paper we provide a method to quantify the potential error resulting from simple appli...

Streams and rivers are important components of the carbon cycle as they transport and transform dissolved organic matter (DOM). Using high‐resolution Fourier‐transform ion cyclotron resonance mass spectrometry, we studied the spatial distribution of DOM at the molecular level at more than 100 sites across a stream network during summer and winter b...

Methane-oxidizing bacteria (MOB) present in the water column mitigate methane (CH4) emissions from hydropower complexes to the atmosphere. By creating a discontinuity in rivers, dams cause large environmental variations, including in CH4 and oxygen concentrations, between upstream, reservoir, and downstream segments. Although highest freshwater met...

Streams and rivers are now recognized to be sites of intense carbon (C) emissions , yet the lack of C emission estimates that integrate beyond individual river systems has slowed their inclusion in landscape C budgets. Here we apply empirical models of CO 2 and CH 4 concentrations and gas exchange continuously along entire fluvial networks to deriv...

Reservoirs are important sources of greenhouse gases (GHGs) to the atmosphere, and their number is rapidly increasing, especially in tropical regions. Accurately predicting their current and future emissions is essential but hindered by fragmented data on the subject, which often fail to include all emission pathways (surface diffusion, ebullition,...

Lake methane (CH4) emissions are largely controlled by aerobic methane‐oxidizing bacteria (MOB) which mostly belong to the classes Alpha‐ and Gammaproteobacteria (Alpha‐ and Gamma‐MOB). Despite the known metabolic and ecological differences between the two MOB groups, their main environmental drivers and their relative contribution to CH4 oxidation...

The past two decades have witnessed growing global concern about excessive greenhouse gas (GHG) emissions by reservoirs and the development of hydropower. Literature review showed that life cycle GHG emissions per energy production of collected global dataset ranged from 0.04 to 237.0 gCO2eq/kW⋅h, with a mean of 25.8 ± 3.0 gCO2eq/kW⋅h. Synthesis fr...

Reservoirs are important sources of greenhouse gases (GHG) to the atmosphere and their number is rapidly increasing, especially in tropical regions. Accurately predicting their current and future emissions is essential but hindered by fragmented data on the subject, which often fail to include all emission pathways (diffusion, ebullition, degassing...

Aerobic methanotrophic bacteria (methanotrophs) use methane as a source of carbon and energy, thereby mitigating net methane emissions from natural sources. Methanotrophs represent a widespread and phylogenetically complex guild, yet the biogeography of this functional group and the factors that explain the taxonomic structure of the methanotrophic...

The distribution and quality of water resources vary dramatically across Canada, and human impacts such as land-use and climate changes are exacerbating uncertainties in water supply and security. At the national level, Canada has no enforceable standards for safe drinking water and no comprehensive water-monitoring program to provide detailed, tim...

Understanding the drivers of aerobic methane (CH4) oxidation (MOX) is paramount in assessing the current and potential future CH4 emissions from freshwater aquatic systems. Regulation of MOX kinetics is a complex function of CH4 and oxygen (O2) concentrations. While MOX activity is usually proportional to the concentration of CH4 itself, the effect...

The boreal biome is characterized by extremely dense and complex fluvial networks that are closely coupled to land. Reconstructing the role that these fluvial networks play in regional carbon (C) budgets requires identifying landscape and environmental drivers of riverine C that operate at the whole network scale and that can be applied across land...

Lakes are biogeochemical hotspots on the landscape, contributing significantly to the global carbon cycle despite their small areal coverage. Observations and models of lake carbon pools and fluxes are rarely explicitly combined through data assimilation despite successful use of this technique in other fields. Data assimilation adds value to both...

All the data and R code required to make the primary figures in Hutchins, R. H. S., Y. T. Prairie, and P. A. del Giorgio. Large-scale landscape drivers of CO2, CH4 and DOC in boreal river networks. Global Biogeochemical Cycles. 2019.

Inland waters have a significant influence on atmospheric methane (CH4) levels. However, processes determining the strength of CH4 emissions from these systems are not well defined. Aerobic oxidation is a major sink of CH4 in freshwater environments and thus an important determinant of aquatic CH4 emissions, yet strikingly little is known about its...

Lakes play an important role in the global carbon cycle, emitting significant amounts of the carbonic greenhouse gases, CO2 and methane (CH4). Nearly all lake studies have reported oxygenated surface waters oversaturated with (and thus continuously emitting) CH4, yet no consistent explanation exists to account for why CH4, which is produced in anox...

Freshwater reservoirs are a known source of greenhouse gas (GHG) to the atmosphere, but their quantitative significance is still only loosely constrained. Although part of this uncertainty can be attributed to the difficulties in measuring highly variable fluxes, it is also the result of a lack of a clear accounting methodology, particularly about...

Formal integration of models and data to test hypotheses about the processes controlling carbon dynamics in lakes is rare, despite the importance of lakes in the carbon cycle. We built a suite of models (n=102) representing different hypotheses about lake carbon processing, fit these models to data from a north-temperate lake using data assimilatio...

Phosphorus and nitrogen are key nutrients that affect abundance and growth of aquatic primary producers but cannot be directly remotely sensed as their dissolved or organic forms do not interact with the remote sensing signal. In addition, other lake water quality variables such as chlorophyll a and Secchi disk depth, have been previously successfu...

Soils export large amounts of organic matter to rivers, and there are still major uncertainties concerning the composition and reactivity of this material, and its fate within the fluvial network. Here we reconstructed the pattern of movement and processing of dissolved organic matter (DOM) along a soil-stream-river continuum under summer base-flow...

To quantify CO2 emissions from water surface of a reservoir that was shaped by flooding the boreal landscape, we developed a daily time-step reservoir biogeochemistry model. We calibrated the model using the measured concentrations of dissolved organic and inorganic carbon (C) in a young boreal hydroelectric reservoir, Eastmain-1 (EM-1), in norther...

Here, we explore the interaction between hydrology and the reactivity of allochthonous dissolved organic carbon (DOCalloch) in determining the potential of DOCalloch to generate CO2 through biological and photo-chemical mineralization in boreal lakes. We developed a mechanistic model that integrates the reactivity continuum (RC) concept to reconstr...

Methane (CH4) emissions from aquatic systems should be coupled to CH4 production, and thus a temperature-dependent process, yet recent evidence suggests that modeling CH4 emissions may be more complex due to the biotic and abiotic processes influencing emissions. We studied the magnitude and regulation of two CH4 pathways—ebullition and diffusion—f...

There is considerable debate on the role of hydroelectric reservoirs for the emission of CO2 and other greenhouse gases. To quantify CO2 emissions from a newly created reservoir that was formed by flooding the boreal landscape we developed a daily time-step reservoir model by integrating a terrestrial and an aquatic ecosystem model. We calibrated t...

Export of carbon (C) from watersheds represents a key component of local and regional C budgets. We explored the magnitude, variability, and drivers of inorganic, organic, and total C exports from 83 temperate catchments in southern Québec, Canada. The average dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and total C (TC) export...

Northern forests are important ecosystems for carbon (C) cycling and lakes within them process and bury large amounts of organic-C. Current burial estimates are poorly constrained and may discount other shifts in organic-C burial driven by global change. Here we analyse a suite of northern lakes to determine trends in organic-C burial throughout th...

Supplementary Figures 1-3, Supplementary Table 1 and Supplementary References.

We explored the whole-lake accumulation of CO2 during winter ice cover and in the hypolimnion during summer stratification, in 15 temperate and boreal lakes, and how these processes vary with lake trophic state and morphometry. We further estimated an annual CO2 budget for each lake that incorporates the fluxes resulting from winter ice-cover and s...

Estimating the distribution of water across the landscape is critical to understanding how local aquatic biogeochemical processes may upscale to regional or continental scales. Whereas technology to estimate the areal extent of inland waters has improved dramatically, predictions of lake bathymetry still rely primarily on correlations with lake are...

Dissolved inorganic carbon (DIC) is present in all natural waters. The concentration of DIC varies from less than 20μM in acidic soft waters to more than 5000μM in highly alkaline hard waters, but ranges between 100 and 1000μM in most systems. DIC is usually the most abundant form of C in water. DIC consists of three main constituents: free CO2 (a...