Bogard, Matthew
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- ItemAgricultural land use impacts aquatic greenhouse gas emissions from wetlands in the Canadian Prairie Pothole Region(AGU, 2025) Logozzo, Laura A.; Soued, Cynthia; Bortolotti, Lauren E.; Badiou, Pascal; Kowal, Paige; Bogard, Matthew J.The Prairie Pothole Region (PPR) is the largest wetland complex in North America, with millions of wetlands punctuating the landscapes of Canada and the United States. Here, wetlands have been dramatically impacted by agricultural land use, with unclear implications for regional to global greenhouse gas (GHG) emissions budgets. By surveying wetlands across all three Canadian prairie provinces in the PPR, we show that emissions patterns of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from aquatic habitats differ among wetlands embedded in cropland versus perennial landcover. Wetlands in cropped landscapes had double the aquatic diffusive emissions (17.8 ± 29.3 vs. 7.7 ± 13.9 g CO2-eq m−2 d−1) largely driven by CH4. Structural equation modeling showed that all three GHGs responded differently to the surrounding landscape properties. Emissions of CH4 were the most sensitive to land use, responding positively to the elevated phosphorus content and lower sulfate content in cropped settings, despite higher organic matter content in wetlands in perennial landscapes. Aquatic N2O emissions were negligible, while CO2 emissions were high, but not strongly related to agricultural land use. While our estimates of aquatic CH4 emissions from PPR wetlands were high (15.6 ± 37.2 mmol CH4 m−2 d−1), accounting for fluxes from vegetated and soil habitats would lead to whole-wetland emissions rates that are lower and comparable to wetlands in other biomes. Our study represents an important step toward understanding wetland emission responses to land use in the PPR and other wetland-rich agricultural landscapes.
- ItemMulti-decadal impacts of effluent loading on phosphorus sorption capacity in a restored wetland(Elsevier, 2025) Mi, Chenxi; Soued, Cynthia; Bortolotti, Lauren E.; Padiou, Pascal; Page, Bryan; Denny, Mariya; Bogard, Matthew J.Natural wetlands are widely used and cost-effective systems for the passive remediation of phosphorus (P)-rich surface waters from various effluent sources. Yet the long-term biogeochemical impacts of effluent loading on wetland P retention capacity are unclear. Here, we had a unique opportunity to document the spatio-temporal evolution of sediment P sorption over a ∼25-year period of constant municipal and industrial effluent loading, as part of a wetland restoration and wastewater treatment strategy in one of the largest restored wetlands in Canada. Sediment P sorption experiments across Frank Lake's three basins revealed a wide spatial variation in sorption capacity, closely linked to sediment geochemistry gradients (Ca, Fe, and Mn). Relative to a similar study ∼25 years prior, P sorption capacity has become exhausted near the effluent inlet, but remarkably, remains elevated throughout the rest of the wetland. Compared to other prairie wetlands and global aquatic ecosystems, Frank Lake has a greater capacity overall to retain P through sediment sorption. Given the paucity of long-term (multi-decade) data on wetland response to effluent loading, we provide key insights into the dynamics of wetland P cycling in human-dominated watersheds.
- ItemSalinity causes widespread restriction of methane emissions from small inland waters(Springer Nature, 2024) Soued, Cynthia; Bogard, Matthew J.; Finlay, Kerri; Bortolotti, Lauren E.; Leavitt, Peter R.; Badiou, Pascal; Knox, Sara H.; Jensen, Sydney; Mueller, Peka; Lee, Sung Ching; Ng, Darian; Wissel, Björn; Chan, Chun Ngai; Page, Bryan; Kowal, PaigeInland waters are one of the largest natural sources of methane (CH4), a potent greenhouse gas, but emissions models and estimates were developed for solute-poor ecosystems and may not apply to salt-rich inland waters. Here we combine field surveys and eddy covariance measurements to show that salinity constrains microbial CH4 cycling through complex mechanisms, restricting aquatic emissions from one of the largest global hardwater regions (the Canadian Prairies). Existing models overestimated CH4 emissions from ponds and wetlands by up to several orders of magnitude, with discrepancies linked to salinity. While not significant for rivers and larger lakes, salinity interacted with organic matter availability to shape CH4 patterns in small lentic habitats. We estimate that excluding salinity leads to overestimation of emissions from small Canadian Prairie waterbodies by at least 81% ( ~ 1 Tg yr−1 CO2 equivalent), a quantity comparable to other major national emissions sources. Our findings are consistent with patterns in other hardwater landscapes, likely leading to an overestimation of global lentic CH4 emissions. Widespread salinization of inland waters may impact CH4 cycling and should be considered in future projections of aquatic emissions.
- ItemComposition and bioreactivity of dissolved organic matter leachates from end members in a mountain to prairie transitional river valley(AGU, 2024) Zhou, Xingzi; Logozzo, Laura A.; Johnston, Sarah Ellen; Zink, Lauren; Amerila, Armi-Lee; Bogard, Matthew J.River organic matter transformations impact the cycling of energy, carbon, and nutrients. The delivery of distinct dissolved organic matter (DOM) sources can alter aquatic DOM cycling and associated biogeochemical processes. Yet DOM source and reactivity are not well-defined for many river systems, including in western Canada. Here, we explore DOM cycling in the mainstem of the Oldman River (stream order 6–7), a heavily regulated river network in southern Alberta (Canada). We compared seasonal river DOM content, composition, and bioavailability with nine endmember leachates from the river valley using optical properties and incubations to estimate biodegradable dissolved organic carbon (BDOC). River DOM composition was most similar to terrestrial soil leachates, followed by autochthonous DOM leachates. River DOM bioavailability was low (BDOC = 0%–16.6%, mean of 7.1%). Endmember leachate bioavailability increased from soils (BDOC = 23.9%–53.7%), to autochthonous sources (fish excretion, macrophytes, biofilm; BDOC = 49.9%–80.0%), to terrestrial vegetation (leaves, shrubs, grass; BDOC > 80%), scaling positively with protein-like DOM content and amount of leachable dissolved organic carbon (DOC), and negatively with aromaticity. Seasonally, DOC concentrations changed little despite >15-fold increases in discharge during spring. River DOM composition shifted modestly toward soil-like endmembers in spring and more bioavailable autochthonous end members in autumn and winter. Low DOM bioavailability in the river mainstem and low DOC yields shown in previous work point to limited internal processing of DOM and limited bioavailable DOM delivery to downstream habitats, possibly due to upstream flow regulation. Our observations provide important insights into the functioning of western Canadian aquatic networks.