Groundwater Dependent Ecosystems in Arid Zones Can Use Ancient Subterranean Carbon as an Energy Source in the Local Food Web

Dean, Joshua

doi:10.1029/2019jg005089

Cited by 4 publications

(3 citation statements)

References 18 publications

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“…Aged signals can therefore be diluted by modern contributions (turnover of litter), but old dates will definitively indicate significant contributions from the decomposition of old organic matter stored in the peat profile. DOC ages can also be dependent on water residence times (Dean, 2019) although this is unlikely to be a significant issue in the blanket peat systems. In these peatlands, water residence times are often short (minutes) as they tend to be hydrologically “flashy” systems (Shuttleworth et al., 2019), generating the majority of flow from surficial flow paths so that DOC from slow flow paths is a minor component of stormflow.…”

Section: Introductionmentioning

confidence: 99%

Carbon Loss Pathways in Degraded Peatlands: New Insights From Radiocarbon Measurements of Peatland Waters

et al. 2022

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Section: Introductionmentioning

confidence: 99%

Carbon Loss Pathways in Degraded Peatlands: New Insights From Radiocarbon Measurements of Peatland Waters

et al. 2022

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“…We therefore lumped them as soil “respiration” (Resp SZ , Reaction 1, Table 1) (Barba et al., 2018; Hanson et al., 2000). Resp DZ (Reaction 2, Table 1) represents respiration in the DZ from sources such as translocated DOC (from SZ), petrogenic carbon (Dean, 2019; Soulet et al., 2018), and deep root exudates ( OC DZ ). It also lumps in the direct input of DIC from deep root respiration, if present (Tune et al., 2020).…”

Section: Methodsmentioning

confidence: 99%

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

Kerins,

Sadayappan,

Zhi

et al. 2024

Water Resources Research

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Terrestrial production and export of dissolved organic and inorganic carbon (DOC and DIC) to streams depends on water flow and biogeochemical processes in and beneath soils. Yet, understanding of these processes in a rapidly changing climate is limited. Using the watershed‐scale reactive‐transport model BioRT‐HBV and stream data from a snow‐dominated catchment in the Rockies, we show deeper groundwater flow averaged about 20% of annual discharge, rising to ∼35% in drier years. DOC and DIC production and export peaked during snowmelt and wet years, driven more by hydrology than temperature. DOC was primarily produced in shallow soils (1.94 ± 1.45 gC/m2/year), stored via sorption, and flushed out during snowmelt. Some DOC was recharged to and further consumed in the deeper subsurface via respiration (−0.27 ± 0.02 gC/m2/year), therefore reducing concentrations in deeper groundwater and stream DOC concentrations at low discharge. Consequently, DOC was primarily exported from the shallow zone (1.62 ± 0.96 gC/m2/year, compared to 0.12 ± 0.02 gC/m2/year from the deeper zone). DIC was produced in both zones but at higher rates in shallow soils (1.34 ± 1.00 gC/m2/year) than in the deep subsurface (0.36 ± 0.02 gC/m2/year). Deep respiration elevated DIC concentrations in the deep zone and stream DIC concentrations at low discharge. In other words, deep respiration is responsible for the commonly‐observed increasing DOC concentrations (flushing) and decreasing DIC concentrations (dilution) with increasing discharge. DIC export from the shallow zone was ~66% of annual export but can drop to ∼53% in drier years. Numerical experiments suggest lower carbon production and export in a warmer, drier future, and a higher proportion from deeper flow and respiration processes. These results underscore the often‐overlooked but growing importance of deeper processes in a warming climate.

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“…Resp SZ represents the net DOC and DIC production from microbial processing of soil organic carbon (OC SZ ) and root respiration and exudates (Roots DOC&DIC ). Resp DZ represents DIC produced in the DZ where, in addition to translocated DOC from the shallow zone, petrogenic carbon (Dean, 2019;Soulet et al, 2018) and deep root exudates (Tune et al, 2020) can also act as sources of DIC. We use the temperature dependence function (f(T) in equation ( 6)) to account for the generally higher respiration rates in the summer, and the soil moisture function (f(S w )) to account for rate dependence on water content.…”

Section: Reaction Networkmentioning

confidence: 99%

BioRT-HBV 1.0: a Biogeochemical Reactive Transport Model at the Watershed Scale

Sadayappan,

Stewart,

Kerins

et al. 2024

Preprint

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Reactive Transport Models (RTMs) are essential for understanding and predicting intertwined ecohydrological and biogeochemical processes on land and in rivers. While traditional RTMs have focused primarily on subsurface processes, recent RTMs integrate hydrological and biogeochemical interactions between land surface and subsurface. These emergent, watershed-scale RTMs are often spatially explicit and require large amount of data and extensive computational expertise. There is however a pressing need to create parsimonious models that require less data and are accessible to scientists with less computational background. Here we introduce BioRT-HBV 1.0 (hereafter BioRT), a watershed-scale, hydro-biogeochemical model that builds upon the widely used, bucket-type HBV model (Hydrologiska Bryåns Vattenavdelning), known for its simplicity and minimal data requirements. BioRT uses the conceptual structure and hydrology output of HBV to simulate processes including solute transport and biogeochemical reactions driven by reaction thermodynamics and kinetics. These reactions include, for example, chemical weathering, soil respiration, and nutrient transformation. This paper presents the model structure and governing equations, demonstrates its utility with examples simulating carbon and nitrogen processes in a headwater catchment. As shown in the examples, when constrained by data, BioRT can be used to illuminate the dynamics of biogeochemical reactions in the invisible, arduous-to-measure subsurface, and their connections to observed solute export in streams and rivers. We posit that such parsimonious models increase model accessibility to users without in-depth computational training. It also can serve as an educational tool that promote pollination of ideas across different fields and foster a more diverse, equal, and inclusive user community.

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Groundwater Dependent Ecosystems in Arid Zones Can Use Ancient Subterranean Carbon as an Energy Source in the Local Food Web

Cited by 4 publications

References 18 publications

Carbon Loss Pathways in Degraded Peatlands: New Insights From Radiocarbon Measurements of Peatland Waters

Carbon Loss Pathways in Degraded Peatlands: New Insights From Radiocarbon Measurements of Peatland Waters

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

BioRT-HBV 1.0: a Biogeochemical Reactive Transport Model at the Watershed Scale

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