Effects of bedrock groundwater discharge on spatial variability of dissolved carbon, nitrogen, and phosphorous concentrations in stream water within a forest headwater catchment

Egusa, Tomohiro; Kumagai, Tomo’omi; Oda, Takayuki; Ohte, Nobuhito

doi:10.1002/hyp.13993

Cited by 3 publications

(1 citation statement)

References 72 publications

(114 reference statements)

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“…For example, for two basins in Northeast US, groundwater seeps led to headwater streams with some of the lowest DOC concentrations observed across the stream network (Vidon et al, 2014;Zimmer et al, 2013). Additionally, spatial studies in Sweden and Japan measured significant negative relationships between the percentage of groundwater and DOC concentrations (Egusa et al, 2021;Peralta-Tapia et al, 2015). The importance of groundwater on DOC concentrations after wildfire was also noted following in Alberta, CAN, where there was no measurable impact of wildfire on DOC concentrations in fens (Davidson et al, 2019) or boreal lakes (Olefeldt et al, 2013).…”

Section: Spatial Stream Network Models Of Docmentioning

confidence: 99%

The influence of burn severity on dissolved organic carbon concentrations across a stream network differs based on seasonal wetness conditions post-fire

Wampler,

Bladon,

Myers-Pigg

2024

Preprint

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Abstract. Large, high severity wildfires in many regions across the globe have increased concerns about their impacts on carbon cycling in watersheds. Altered sources of carbon and changes in catchment hydrology after wildfire can lead to shifts in dissolved organic carbon concentrations (DOC) in streams, which can have negative impacts on aquatic ecosystem health and downstream drinking water treatment. Despite its importance, post-fire DOC responses remain relatively unconstrained in the literature, and we lack critical knowledge of how burn severity, landscape elements, and climate interact to affect DOC concentrations. To improve our understanding of the impact of burn severity on DOC concentrations, we measured DOC at ~100 sites across a stream network extending upstream, within, and downstream of a large, high severity wildfire in Oregon, USA. We collected samples across the study sub-basin during four distinct seasonal wetness conditions. We used our high spatial resolution data to develop spatial stream network (SSN) models to predict DOC across the stream network and to improve our understanding of the controls on DOC concentrations. Spatially, we found no obvious wildfire signal—instead we observed a pattern of increasing DOC concentrations from the high elevation headwaters to the sub-basin outlet, while the mainstem maintained consistently low DOC concentrations. This suggests that effects from large wildfires may be “averaged” out at higher stream orders and larger spatial scales. With our DOC measurements grouped by burn severity group, we observed a significant decrease in the variability of DOC concentrations in the moderate and high burn severity sub-catchments. However, our SSN models were able to predict decreases in DOC concentrations with increases in burn severity across the stream network. Decreases in DOC concentrations were also highly variable across seasonal wetness conditions, with the greatest (-1.40 to -1.64 mg L-1) decrease in the high severity group during the wetting season. Additionally, our models indicated that in all seasons, baseflow index was more influential in predicting DOC concentrations than burn severity, indicating that groundwater discharge can obscure the impacts of wildfire in a stream network. Overall, our results suggest that landscape characteristics can regulate the DOC response to wildfire. Moreover, our results also indicate that the seasonal timing of sampling can influence the observed response of DOC concentrations to wildfire.

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Section: Spatial Stream Network Models Of Docmentioning

confidence: 99%

The influence of burn severity on dissolved organic carbon concentrations across a stream network differs based on seasonal wetness conditions post-fire

Wampler,

Bladon,

Myers-Pigg

2024

Preprint

View full text Add to dashboard Cite

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Weathered bedrock converts hydrological processes in loess hilly-gully critical zone

Luo,

Fan,

Shao

et al. 2023

Journal of Hydrology

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The influence of burn severity on dissolved organic carbon concentrations across a stream network differs based on seasonal wetness conditions

Wampler,

Bladon,

Myers-Pigg

2024

Biogeosciences

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Abstract. Large, high-severity wildfires in many regions across the globe have increased concerns about their impacts on carbon cycling in watersheds. Altered sources of carbon and changes in catchment hydrology after wildfire can lead to shifts in dissolved organic carbon (DOC) concentrations in streams, which can have negative impacts on aquatic ecosystem health and downstream drinking-water treatment. Despite its importance, post-fire DOC responses remain relatively unconstrained in the literature, and we lack critical knowledge of how burn severity, landscape elements, and climate interact to affect DOC concentrations. To improve our understanding of the impact of burn severity on DOC concentrations, we measured DOC at 129 sites across a stream network extending upstream, within, and downstream of a large, high-severity wildfire in Oregon, USA. We collected samples across the study sub-basin during four distinct seasonal wetness conditions. We used our high-spatial-resolution data to develop spatial stream network (SSN) models to predict DOC across the stream network and to improve our understanding of the controls on DOC concentrations. Spatially, we found no obvious wildfire signal – instead, we observed a pattern of increasing DOC concentrations from the high-elevation headwaters to the sub-basin outlet, while the mainstem maintained consistently low DOC concentrations. This suggests that effects from large wildfires may be “averaged” out at higher stream orders and larger spatial scales. When we grouped DOC concentrations by burn severity group, we observed a significant decrease in the variability of DOC concentrations in the moderate and high burn severity sub-catchments. However, our SSN models were able to predict decreases in DOC concentrations with increases in burn severity across the stream network. Decreases in DOC concentrations were also highly variable across seasonal wetness conditions, with the greatest (−1.40 to −1.64 mg L−1) decrease occurring in the high-severity group during the wetting season. Additionally, our models indicated that in all seasons, baseflow index was more influential in predicting DOC concentrations than burn severity was, indicating that groundwater discharge can obscure the impacts of wildfire in a stream network. Overall, our results suggested that landscape characteristics can regulate the DOC response to wildfire. Moreover, our results also indicated that the seasonal timing of sampling can influence the observed response of DOC concentrations to wildfire.

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Effects of bedrock groundwater discharge on spatial variability of dissolved carbon, nitrogen, and phosphorous concentrations in stream water within a forest headwater catchment

Cited by 3 publications

References 72 publications

The influence of burn severity on dissolved organic carbon concentrations across a stream network differs based on seasonal wetness conditions post-fire

The influence of burn severity on dissolved organic carbon concentrations across a stream network differs based on seasonal wetness conditions post-fire

Weathered bedrock converts hydrological processes in loess hilly-gully critical zone

The influence of burn severity on dissolved organic carbon concentrations across a stream network differs based on seasonal wetness conditions

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