Investigating Spatial and Temporal Nitrogen Dynamics in a Forested Headwater Stream Over the Course of an Annual Drying Event

Journal of Geophysical Research Biogeosciences, Journal Year: 2025, Volume and Issue: 130(4)

Published: March 27, 2025

Abstract Headwater streams make up nearly 80% of the stream network by length and play an important role in shaping physical, chemical, biological functions downstream waters. In Southeastern US, these systems are beginning to experience increases frequency duration drying, but it is unclear how increased drying will impact water quality. To begin address this issue, we examined nitrogen dynamics a forested headwater across annual event. The event was divided into seasonal wet (March–June), dry‐down (June–October), rewet (November–March) periods. We used combination quality sensors at watershed outlet, spatially distributed synoptic sampling net denitrification conditions physicochemical variables watershed, series potential experiments examine variation biogeochemical state At nitrate concentrations were positively correlated with watershed‐scale connectivity during period, while streamflow period. Throughout varied more seasons than space, greater Further, temperature, nitrate, ammonium inversely related streamflow. Finally, measurements confirmed period experienced highest rates. Our results highlight connection between humid systems, providing key information for developing predictive understanding streams.

Language: Английский

BioRT‐HBV 1.0: A Biogeochemical Reactive Transport Model at the Watershed Scale

Journal of Advances in Modeling Earth Systems, Journal Year: 2024, Volume and Issue: 16(12)

Published: Nov. 30, 2024

Abstract Reactive Transport Models (RTMs) are essential tools for understanding and predicting intertwined ecohydrological biogeochemical processes on land in rivers. While traditional RTMs have focused primarily subsurface processes, recent watershed‐scale integrated interactions between surface subsurface. These emergent, often spatially explicit require extensive data, computational power, expertise. There is however a pressing need to create parsimonious models that minimal data accessible scientists with limited background. To end, we developed BioRT‐HBV 1.0, watershed‐scale, hydro‐biogeochemical RTM builds upon the widely used, bucket‐type HBV model known its simplicity requirements. uses conceptual structure hydrology output of simulate including advective solute transport reactions depend reaction thermodynamics kinetics. include, example, chemical weathering, soil respiration, nutrient transformation. The time series weather (air temperature, precipitation, potential evapotranspiration) initial conditions water, soils, rocks as input, times rates concentrations waters This paper presents governing equations demonstrates utility examples simulating carbon nitrogen headwater catchment. As shown examples, can be used illuminate dynamics invisible, arduous‐to‐measure subsurface, their influence observed stream or river chemistry export. With easy‐to‐use graphical user interface, useful research tool users without in‐depth training. It additionally serve an educational promotes pollination ideas across disciplines foster diverse, equal, inclusive community.

Language: Английский

Hydrology Outweighs Temperature in Driving Production and Export of Dissolved Carbon in a Snowy Mountain Catchment

Water Resources Research, Journal Year: 2024, Volume and Issue: 60(7)

Published: July 1, 2024

Abstract Terrestrial production and export of dissolved organic inorganic carbon (DOC DIC) to streams depends on water flow biogeochemical processes in beneath soils. Yet, understanding these a rapidly changing climate is limited. Using the watershed‐scale reactive‐transport model BioRT‐HBV stream data from snow‐dominated catchment Rockies, we show deeper groundwater averaged about 20% annual discharge, rising ∼35% drier years. DOC DIC peaked during snowmelt wet years, driven more by hydrology than temperature. was primarily produced shallow soils (1.94 ± 1.45 gC/m 2 /year), stored via sorption, flushed out snowmelt. Some recharged further consumed subsurface respiration (−0.27 0.02 therefore reducing concentrations at low discharge. Consequently, exported zone (1.62 0.96 /year, compared 0.12 /year zone). both zones but higher rates (1.34 1.00 /year) deep (0.36 /year). Deep elevated In other words, responsible for commonly‐observed increasing (flushing) decreasing (dilution) with ~66% can drop ∼53% Numerical experiments suggest lower warmer, future, proportion processes. These results underscore often‐overlooked growing importance warming climate.

Language: Английский