A5061832508- Atmospheric and Environmental Gas Dynamics
- Marine and coastal ecosystems
- Methane Hydrates and Related Phenomena
- Hydrocarbon exploration and reservoir analysis
- Soil and Water Nutrient Dynamics
- Fish Ecology and Management Studies
- Hydrology and Watershed Management Studies
- Water Resources and Management
- Groundwater flow and contamination studies
- Geology and Paleoclimatology Research
- Peatlands and Wetlands Ecology
- Climate variability and models
- Arctic and Antarctic ice dynamics
- Climate change and permafrost
- Geological formations and processes
- Oceanographic and Atmospheric Processes
- Plant Water Relations and Carbon Dynamics
- Ecology and biodiversity studies
- Climate Change Policy and Economics
- CO2 Sequestration and Geologic Interactions
- Ocean Acidification Effects and Responses
- Soil erosion and sediment transport
- Air Quality Monitoring and Forecasting
- Vehicle emissions and performance
- Oil Spill Detection and Mitigation
University of Geneva
2013-2025
University of Waterloo
2021-2024
Université du Québec à Montréal
2015-2022
Charles Humbert 8
2020
Swiss Federal Institute of Aquatic Science and Technology
2010-2017
Baum Consult
2017
ETH Zurich
2010-2016
Environmental Protection Agency
2016
Chongqing Institute of Green and Intelligent Technology
2016
GEOMAR Helmholtz Centre for Ocean Research Kiel
2010
Collectively, reservoirs created by dams are thought to be an important source of greenhouse gases (GHGs) the atmosphere. So far, efforts quantify, model, and manage these emissions have been limited data availability inconsistencies in methodological approach. Here, we synthesize reservoir CH4, CO2, N2O emission with three main objectives: (1) generate a global estimate GHG from reservoirs, (2) identify best predictors emissions, (3) consider effect methodology on estimates. We that water...
Lakes and impoundments are an important source of methane (CH4), a potent greenhouse gas, to the atmosphere. A recent analysis shows aquatic productivity (i.e., eutrophication) is driver CH4 emissions from lentic waters. Considering that will increase over next century due climate change growing human population, concomitant in may occur. We simulate eutrophication waters under scenarios future nutrient loading inland show enhanced lakes substantially these systems (+30-90%) century. This...
Lakes and impoundments are important sources of greenhouse gases (GHG: i.e., CO
Methane emission pathways and their importance were quantified during a yearlong survey of temperate hydropower reservoir. Measurements using gas traps indicated very high ebullition rates, but due to the stochastic nature mass balance approach was crucial deduce system-wide methane sources losses. diffusion from sediment generally low seasonally stable did not account for concentration dissolved measured in reservoir discharge. A strong positive correlation between water temperature...
Inland waters transport and transform substantial amounts of carbon account for ∼18% global methane emissions. Large reservoirs with higher areal release rates than natural contribute significantly to freshwater However, there are millions small dams worldwide that receive trap high loads organic can therefore potentially emit significant the atmosphere. We evaluated effect damming on emissions in a central European impounded river. Direct comparison riverine reservoir reaches, where...
Abstract Methane (CH 4 ) emissions from aquatic systems should be coupled to CH production, and thus a temperature‐dependent process, yet recent evidence suggests that modeling may more complex due the biotic abiotic processes influencing emissions. We studied magnitude regulation of two pathways—ebullition diffusion—from 10 shallow ponds 3 lakes in Québec. Ebullitive fluxes averaged 4.6 ± 4.1 mmol m −2 d −1 , contributing ∼56% total (diffusive + ebullitive) In lakes, ebullition only...
Tropical reservoirs have been identified as important methane (CH(4)) sources to the atmosphere, primarily through turbine and downstream degassing. However, importance of ebullition (gas bubbling) remains unclear. We hypothesized that is a disproportionately large CH(4) source from with dendritic littoral zones because hot spots occurring where rivers supply allochthonous organic material. explored this hypothesis in Lake Kariba (Zambia/Zimbabwe; surface area >5000 km(2)) by surveying bays...
Methane (CH4) strongly contributes to observed global warming. As natural CH4 emissions mainly originate from wet ecosystems, it is important unravel how climate change may affect these emissions. This especially true for ebullition (bubble flux sediments), a pathway that has long been underestimated but generally dominates Here we show remarkably strong relationship between and temperature across wide range of freshwater ecosystems on different continents using multi-seasonal data the...
Organic carbon (OC) burial and greenhouse gas emission of inland waters plays an increasingly evident role in the balance continents, particularly young reservoirs tropics emit methane (CH 4 ) at high rates. Here we show that old, temperate reservoir acts simultaneously as a strong OC sink CH source, because sedimentation rate supplies reactive organic matter to deep, anoxic sediment strata, fuelling methanogenesis bubble (ebullition) from sediment. Damming river has resulted build‐up highly...
Ebullition (bubbling) is an important mechanism for the transfer of methane (CH4) from shallow waters to atmosphere. Because their stochastic nature, however, ebullition fluxes are difficult accurately resolve. Hydroacoustic surveys have potential significantly improve spatiotemporal observation emission fluxes, but knowledge bubble size distribution also necessary assess local, regional, and global water body CH4 estimates. Therefore, we explore importance small-scale flux variability on...
Contrasting the paradigm that methane is only produced in anoxic conditions, recent discoveries show oxic production (OMP, aka paradox) occurs oxygenated surface waters worldwide. OMP drivers and their contribution to global emissions, however, are not well constrained. In four adjacent pre-alpine lakes, we determine net rates using two mass balance approaches, accounting for sources sinks. We find three out of studied often as dominant source diffusive emissions. Correlations versus...
Abstract. Greenhouse gas budgets quantified via land-surface eddy covariance (EC) flux sites differ significantly from those obtained inverse modeling. A possible reason for the discrepancy between methods may be our gap in quantitative knowledge of methane (CH4) fluxes. In this study we carried out EC measurements during two intensive campaigns summer 2008 to quantify a hydropower reservoir and link its temporal variability environmental driving forces: water temperature pressure changes...
[1] A natural carbon dioxide (CO2) seep was discovered during an expedition to the southern German North Sea (October 2008). Elevated CO2 levels of ∼10–20 times above background were detected in seawater a salt dome ∼30 km north East-Frisian Island Juist. single elevated value 53 higher than measured, indicating possible point source from seafloor. Measured pH values around 6.8 support modeled for observed high concentration. These results are presented context seepage detection, light...
Abstract The potent greenhouse gas methane (CH 4 ) is readily emitted from tropical reservoirs, often via ebullition (bubbles). This highly stochastic emission pathway varies in space and time, however, hampering efforts to accurately assess total CH emissions water bodies. We systematically studied both the spatial temporal scales of variability a river inflow bay Brazilian reservoir. conducted multiple resolved surveys using hydroacoustic approach supplemented with bubble traps over...
Abstract The occurrence of oxic methane production (OMP) has been reported for numerous aquatic ecosystems. Its seasonal dynamics and contribution to global () emissions remains uncertain, however, due the lack measurements constraining spatial temporal variability OMP. In this study, we used data collected over 4 yrs with three types models estimate net production/consumption in surface mixed layer a eutrophic lake. These allowed us assess lateral fluxes' on estimations. All model results...
Abstract. We present the first high-resolution (500 m × 500 m) gridded methane (CH4) emission inventory for Switzerland, which integrates 90 % of national totals reported to United Nations Framework Convention on Climate Change (UNFCCC) and recent CH4 flux studies conducted by research groups across Switzerland. In addition anthropogenic emissions, we also include natural semi-natural fluxes, i.e., emissions from lakes reservoirs, wetlands, wild animals as well uptake forest soils. National...
Abstract An increasing number of rivers is being dammed, particularly in the tropics, and reservoir water surfaces can be a substantial anthropogenic source greenhouse gases. On average, 80% CO 2 ‐equivalent emission reservoirs globally has been attributed to CH 4 , which predominantly emitted via ebullition. Since ebullition highly variable across space time, both measuring upscaling an entire challenging, estimates are therefore not well constrained. We measured at high spatial resolution...
Abstract Fluxes of carbon dioxide (CO 2 ) and methane (CH 4 from hydroelectric water supply reservoirs are receiving increasing attention around the world with a number research groups having undertaken measurements these emissions across range lakes located in different climates landscapes. The use floating chambers (aka flux chambers) is most common technique for direct measurement fluxes. However, relative performance systems, especially chamber designs, not well documented. We report...
In the late 19th century, F.-A. Forel led investigations of Rhone River delta area Lake Geneva that resulted in discovery a textbook example river-fed system containing impressive subaquatic channels. Well ahead marine counterparts, scientific observations and interpretations water currents shaping edifice for first time documented how underflow carry cold, suspension-laden waters from river mouth all way to deep basin. These early laid basis follow-up studies 20th 21th centuries. Sediment...