Dominic Vachon

@article{https://doi.org/10.1111/gcb.15448,

title = {Integrating carbon emission, accumulation and transport in inland waters to understand their role in the global carbon cycle},

author = {Dominic Vachon and Ryan A Sponseller and Jan Karlsson},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.15448},

doi = {https://doi.org/10.1111/gcb.15448},

year  = {2021},

date = {2021-01-01},

journal = {Global Change Biology},

volume = {27},

number = {4},

pages = {719-727},

abstract = {Abstract Inland waters receive a significant quantity of carbon (C) from land. The fate of this C during transit, whether it is emitted to the atmosphere, accumulated in sediments or transported to the ocean, can considerably reshape the landscape C balance. However, these different fates of terrestrial C are not independent but are instead linked via several catchment and aquatic processes. Thus, according to mass conservation, any environmental change inducing a shift in a particular C fate should come at the expense of at least one other fate. Nonetheless, studies that have investigated C emission, accumulation and transport concertedly are scarce, resulting in fragmented knowledge of the role of inland waters in the global C cycle. Here, we propose a framework to understand how different C fates in aquatic systems are interlinked and covary under environmental changes. First, to explore how C fates are currently distributed in streams, rivers, reservoirs and lakes, we compiled data from the literature and show that ‘C fate allocation’ varies widely both within and among inland water systems types. Secondly, we developed a framework that integrates C fates in any inland water system by identifying the key processes underlying their linkages. Our framework places the partitioning between the different C forms, and how this is controlled by export from land, internal transformations and hydrology, as central to understanding C fate allocation. We argue that, by focusing on a single fate, studies could risk drawing misleading conclusions regarding how environmental changes will alter the role of inland waters in the global C cycle. Our framework thus allows us to holistically assess the consequences of such changes on coupled C fluxes, setting a foundation for understanding the contemporary and future fate of land-derived C in inland water systems.},

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pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1002/lol2.10161,

title = {Methane emission offsets carbon dioxide uptake in a small productive lake},

author = {Dominic Vachon and Timon Langenegger and Daphne Donis and Stan E Beaubien and Daniel F McGinnis},

url = {https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.1002/lol2.10161},

doi = {https://doi.org/10.1002/lol2.10161},

year  = {2020},

date = {2020-01-01},

journal = {Limnology and Oceanography Letters},

volume = {5},

number = {6},

pages = {384-392},

abstract = {Abstract Here, we investigate the importance of net CH4 production and emissions in the carbon (C) budget of a small productive lake by monitoring CH4, CO2, and O2 for two consecutive years. During the study period, the lake was mostly a net emitter of both CH4 and CO2, while showing positive net ecosystem production. The analyses suggest that during the whole study period, 32% ± 26% of C produced by net ecosystem production was ultimately converted to CH4 and emitted to the atmosphere. When converted to global warming potential, CH4 emission (in CO2 equivalents) was about 3–10 times higher than CO2 removal from in-lake net ecosystem production over 100-yr and 20-yr time frames, respectively. Although more work in similar systems is needed to generalize these findings, our results provide evidence of the important greenhouse gas imbalance in human-impacted aquatic systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1002/lol2.10135,

title = {Paired O2–CO2 measurements provide emergent insights into aquatic ecosystem function},

author = {Dominic Vachon and Steven Sadro and Matthew J Bogard and Jean-François Lapierre and Helen M Baulch and James A Rusak and Blaize A Denfeld and Alo Laas and Marcus Klaus and Jan Karlsson and Gesa A Weyhenmeyer and Paul A del Giorgio},

url = {https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.1002/lol2.10135},

doi = {https://doi.org/10.1002/lol2.10135},

year  = {2020},

date = {2020-01-01},

journal = {Limnology and Oceanography Letters},

volume = {5},

number = {4},

pages = {287-294},

abstract = {Scientific Significance Statement Metabolic stoichiometry predicts that dissolved oxygen (O2) and carbon dioxide (CO2) in aquatic ecosystems should covary inversely; however, field observations often diverge from theoretical expectations. Here, we propose a suite of metrics describing this O2 and CO2 decoupling and introduce a conceptual framework for interpreting these metrics within aquatic ecosystems. Within this framework, we interpret cross-system patterns of high-frequency O2 and CO2 measurements in 11 northern lakes and extract emergent insights into the metabolic behavior and the simultaneous roles of chemical and physical forcing in shaping ecosystem processes. This approach leverages the power of high-frequency paired O2–CO2 measurements, and yields a novel, integrative aquatic system typology which can also be applicable more broadly to streams and rivers, wetlands and marine systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1002/lno.11172,

title = {Influence of water column stratification and mixing patterns on the fate of methane produced in deep sediments of a small eutrophic lake},

author = {Dominic Vachon and Timon Langenegger and Daphne Donis and Daniel F McGinnis},

url = {https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.1002/lno.11172},

doi = {https://doi.org/10.1002/lno.11172},

year  = {2019},

date = {2019-01-01},

journal = {Limnology and Oceanography},

volume = {64},

number = {5},

pages = {2114-2128},

abstract = {Abstract Methane (CH4), a potent greenhouse gas, is produced in and emitted from lakes at globally significant rates. The drivers controlling the proportion of produced CH4 that will reach the atmosphere, however, are still not well understood. We sampled a small eutrophic lake (Soppensee, Switzerland) in 2016–2017 for CH4 concentrations profiles and emissions, combined with water column hydrodynamics to investigate the fate of CH4 produced in hypolimnetic sediments. Using a mass balance approach for the periods between April and October of both years, net CH4 production rates in hypolimnetic sediments ranged between 11.4 and 17.7 mmol m−2 d−1, of which 66–88% was stored in the hypolimnion, 13–27% was diffused to the epilimnion, and 6–7% left the sediments via ebullition. Combining these results with a process-based model we show that water column turbulent diffusivity (K z) had a major influence on the fate of produced CH4 in the sediments, where higher K z values potentially lead to greater proportion being oxidized and lower K z lead to a greater proportion being stored. During fall when the water column mixes, we found that a greater proportion of stored CH4 is emitted if the lake mixes rapidly, whereas a greater proportion will be oxidized if the water column mixes more gradually. This work highlights the central role of lake hydrodynamics in regulating CH4 dynamics and further suggests the potential for CH4 production and emissions to be sensitive to climate-driven alterations in lake mixing regimes and stratification.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1002/lno.10454,

title = {Reconstructing the seasonal dynamics and relative contribution of the major processes sustaining CO2 emissions in northern lakes},

author = {Dominic Vachon and Christopher T Solomon and Paul A del Giorgio},

url = {https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.1002/lno.10454},

doi = {https://doi.org/10.1002/lno.10454},

year  = {2017},

date = {2017-01-01},

journal = {Limnology and Oceanography},

volume = {62},

number = {2},

pages = {706-722},

abstract = {Abstract Lake CO2 emissions are an important component of the carbon balance of northern landscapes, yet the temporal dynamics of the underlying mechanisms sustaining CO2 emissions are less understood. Here, we reconstruct the major biotic and abiotic processes influencing CO2 dynamics over an annual cycle in three limnologically different lakes, using a combination of empirical measurements and process-based modeling. Our results suggest that the relative importance of each process sustaining CO2 emissions is not only variable among lakes, but also highly variable among seasons within one lake. Spring CO2 emissions were largely sustained by the release of under ice accumulation (between about 50–100%), although photo-chemical DOC mineralization and hydrologic CO2 loading were also relatively important. In summer, due to warmer temperature, pelagic and benthic metabolism were the main sources of CO2 emissions. In the fall, lake CO2 emissions were generally sustained by hydrologic CO2 inputs, while hypolimnetic CO2 accumulation and release also contributed to fall CO2 emission in the deepest lake. On an annual basis, lake CO2 emissions ranged between 21.4 g C m−2 yr−1 and 55.5 g C m−2 yr−1. Our results confirm that the major processes all contributed significantly to CO2 emissions, but their relative contributions were modulated by the seasonal patterns in climate and hydrology, and by differences in morphology and organic carbon inputs among lakes. These lake- and season-specific features need to be considered both in the upscaling of lake processes at regional scales, and in predicting lake CO2 emissions under scenarios of climate and environmental change.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}