River ecosystem metabolism and carbon biogeochemistry in a changing world

Nature, Journal Year: 2023, Volume and Issue: 613(7944), P. 449 - 459

Published: Jan. 18, 2023

Language: Английский

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The status and stability of permafrost carbon on the Tibetan Plateau

Earth-Science Reviews, Journal Year: 2020, Volume and Issue: 211, P. 103433 - 103433

Published: Nov. 5, 2020

Language: Английский

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Toward catchment hydro‐biogeochemical theories

Wiley Interdisciplinary Reviews Water, Journal Year: 2020, Volume and Issue: 8(1)

Published: Dec. 3, 2020

Abstract Headwater catchments are the fundamental units that connect land to ocean. Hydrological flow and biogeochemical processes intricately coupled, yet their respective sciences have progressed without much integration. Reaction kinetic theories prescribe rate dependence on environmental variables (e.g., temperature water content) advanced substantially, mostly in well‐mixed reactors, columns, warming experiments considering characteristics of hydrological at catchment scale. These shown significant divergence from observations natural systems. On other hand, theories, including transit time theory, substantially not been incorporated into understanding reactions Here we advocate for development integrated hydro‐biogeochemical across gradients climate, vegetation, geology conditions. The lack such presents barriers mechanisms forecasting future Critical Zone under human‐ climate‐induced perturbations. Although integration has started co‐located measurements well way, tremendous challenges remain. In particular, even this era “big data,” still limited by data will need (1) intensify beyond river channels characterize vertical connectivity broadly shallow deep subsurface; (2) expand older dating scales reflected stable isotopes; (3) combine use reactive solutes, nonreactive tracers, (4) augment environments undergoing rapid changes. To develop it is essential engage models all stages model‐informed collection strategies maximize usage; adopt a “simple but simplistic,” or fit‐for‐purpose approach include process‐based models; blend data‐driven framework “theory‐guided science.” Within hypothesis testing, model‐data fusion can advance mechanistically link catchments' internal structures external drivers functioning. It only field hydro‐biogeochemistry, also enable hind‐ fore‐casting serve society large. Broadly, education cultivate thinkers intersections traditional disciplines with hollistic approaches interacting complex earth This article categorized under: Engineering Water > Methods

Language: Английский

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River water quality shaped by land–river connectivity in a changing climate

Nature Climate Change, Journal Year: 2024, Volume and Issue: 14(3), P. 225 - 237

Published: March 1, 2024

Language: Английский

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Distinct Source Water Chemistry Shapes Contrasting Concentration‐Discharge Patterns

Water Resources Research, Journal Year: 2019, Volume and Issue: 55(5), P. 4233 - 4251

Published: April 15, 2019

Abstract Understanding concentration‐discharge (C‐Q) relationships are essential for predicting chemical weathering and biogeochemical cycling under changing climate anthropogenic conditions. Contrasting C‐Q have been observed widely, yet a mechanistic framework that can interpret diverse patterns remains elusive. This work hypothesizes seemingly disparate driven by switching dominance of end‐member source waters their contrasts arising from subsurface heterogeneity. We use data Coal Creek, high‐elevation mountainous catchment in Colorado, recently developed watershed reactive transport model (BioRT‐Flux‐PIHM). Sensitivity analysis Monte‐Carlo simulations (500 cases) show reaction kinetics thermodynamics distribution materials across depths govern the chemistry gradients shallow soil water deeper groundwater entering stream. The alternating organic‐poor geo‐solute‐rich dry conditions organic‐rich geo‐solute‐poor during spring melt leads to flushing pattern dissolved organic carbon dilution geogenic solutes (e.g., Na, Ca, Mg). In addition, extent concentration regulates power law slopes ( b ) via general equation . At low ratios versus concentrations (C ratio = C sw /C gw < 0.6), occurs; at high > 1.8), arises; chemostasis occurs between. quantitatively interprets values 11 (dissolved carbon, P, NO 3 − , K, Si, Mg, Al, Mn, Fe) three catchments (Coal Shale Hills, Plynlimon) differing climate, geologic, land cover indicates potentially broad regulation heterogeneity determining wide applications this quantifying values, which implications transformation scale.

Language: Английский

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Temperature controls production but hydrology regulates export of dissolved organic carbon at the catchment scale

Hydrology and earth system sciences, Journal Year: 2020, Volume and Issue: 24(2), P. 945 - 966

Published: Feb. 27, 2020

Abstract. Lateral carbon flux through river networks is an important and poorly understood component of the global budget. This work investigates how temperature hydrology control production export dissolved organic (DOC) in Susquehanna Shale Hills Critical Zone Observatory Pennsylvania, USA. Using field measurements daily stream discharge, evapotranspiration, DOC concentration, we calibrated catchment-scale biogeochemical reactive transport model BioRT-Flux-PIHM (Biogeochemical Reactive Transport–Flux–Penn State Integrated Hydrologic Model, BFP), which met satisfactory standard a Nash–Sutcliffe efficiency (NSE) value greater than 0.5. We used to estimate compare rates (Rp; sum local individual grid cells) rate (Re; product concentration discharge at outlet, or load). Results showed that Rp varied by less order magnitude, primarily depending on seasonal temperature. In contrast, Re more 3 orders magnitude was strongly associated with variation hydrological connectivity. summer, high evapotranspiration dried disconnected hillslopes from stream, driving its maximum but minimum. During this period, only exported organic-poor groundwater organic-rich soil water swales bordering stream. The produced accumulated later flushed out during wet cold period (winter spring) when peaked as reconnected uphill reached reproduced observed concentration–discharge (C–Q) relationship characterized unusual flushing–dilution pattern concentrations intermediate indicating three end-members source waters. A sensitivity analysis indicated nonlinearity caused shifts relative contribution different waters under flow conditions. At low reflected chemistry groundwater; dominated swales; concentration. persisted regardless long deeper remained (<18 % streamflow). When increased above 18 %, comparable amounts swale mixed masked swales. case, C–Q patterns switched flushing-only increasing discharge. These results depict conceptual catchment serves producer storage reservoir for hot dry conditions transitions into exporter study also illustrates controls – paths, respectively can create temporal asynchrony scale. Future warming extremes could accentuate asynchrony, occurring periods lateral dominating major storm events.

Language: Английский

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Streams as Mirrors: Reading Subsurface Water Chemistry From Stream Chemistry

Water Resources Research, Journal Year: 2021, Volume and Issue: 58(1)

Published: Oct. 22, 2021

Abstract The shallow and deep hypothesis suggests that stream concentration‐discharge (CQ) relationships are shaped by distinct source waters from different depths. Under this hypothesis, baseflows typically dominated groundwater mostly reflect chemistry, whereas high flows soil water chemistry. Aspects of draw on applications like end member mixing analyses hydrograph separation, yet direct data support for the remains scarce. This work tests using co‐located measurements water, groundwater, streamwater chemistry at two intensively monitored sites, W‐9 catchment Sleepers River (Vermont, United States) Hafren Plynlimon (Wales). At both depth profiles subsurface CQ 10 solutes analyzed broadly consistent with hypothesis. Solutes more abundant (e.g., calcium) exhibit dilution patterns (concentration decreases increasing discharge). Conversely, enriched in soils nitrate) generally flushing increases may hold true catchments share such biogeochemical stratifications subsurface. Soil chemistries were estimated high‐ low‐flow average relative errors ranging 24% to 82%. indicates streams mirror waters: can be used infer scarcely measured especially where there members.

Language: Английский

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Archetypes and Controls of Riverine Nutrient Export Across German Catchments

Water Resources Research, Journal Year: 2021, Volume and Issue: 57(4)

Published: March 14, 2021

Abstract Elevated nutrient inputs challenge the health and functioning of aquatic ecosystems. To improve riverine water quality management, it is necessary to understand underlying biogeochemical physical processes, anthropogenic drivers their interactions at catchment scale. We hypothesize that spatial heterogeneity sources dominantly controls variability in‐stream concentration dynamics among catchments. investigated mean nitrate (NO 3 − ), phosphate (PO 4 3− total organic carbon (TOC) concentrations concentration‐discharge ( C‐Q ) relationships in 787 German catchments a newly assembled data base, covering wide range physiographic settings. linked metrics characteristics using partial least squares regressions random forests. found archetypal patterns with enrichment dominating NO TOC, dilution PO export. Both variance sites increased agricultural land use. argue subsurface denitrification can buffer high nitrogen cause decline depth, resulting chemodynamic, strongly positive patterns. Mean were related point sources, though low predictive power suggests effects unaccounted processes. In contrast, diffuse explained observed TOC levels positively abundance riparian wetlands, while hydrological descriptors important for explaining dynamics. Our study shows strong modulation by natural dynamics, only dominate across Germany.

Language: Английский

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Spatial and Temporal Variability in Concentration‐Discharge Relationships at the Event Scale

Water Resources Research, Journal Year: 2021, Volume and Issue: 57(10)

Published: Sept. 29, 2021

Abstract The analysis of concentration‐discharge (C‐Q) relationships from low‐frequency observations is commonly used to assess solute sources, mobilization, and reactive transport processes at the catchment scale. High‐frequency concentration measurements are increasingly available offer additional insights into event‐scale export dynamics. However, only few studies have integrated inter‐annual C‐Q relationships. Here, we analyze high‐frequency specific conductance (EC), nitrate (NO 3 ‐N) concentrations spectral absorbance 254 nm (SAC , as a proxy for dissolved organic carbon) over two year period four neighboring catchments in Germany ranging more pristine forested agriculturally managed settings. We apply an method that adds hysteresis term established power law model so intercept, slope can be characterized simultaneously. found inter‐event variability were most pronounced SAC all NO ‐N catchments. event responses smallest closely coupled explainable by antecedent conditions hint common near‐stream source. In contrast, patterns EC agricultural without buffer zones around streams less variable similar relationship indicating homogeneity mobilization time. Event‐scale thus added key functioning whenever contrasted with responses. Analyzing long‐term behavior one coherent framework helps disentangle these scattered patterns.

Language: Английский

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Climate Controls on River Chemistry

Earth s Future, Journal Year: 2022, Volume and Issue: 10(6)

Published: May 16, 2022

Abstract How does climate control river chemistry? Existing literature has examined extensively the response of chemistry to short‐term weather conditions from event seasonal scales. Patterns and drivers long‐term, baseline have remained poorly understood. Here we compile analyze data 506 minimally impacted rivers (412,801 points) in contiguous United States (CAMELS‐Chem) identify patterns chemistry. Despite distinct sources diverse reaction characteristics, a universal pattern emerges for 16 major solutes at continental scale. Their long‐term mean concentrations ( C m ) decrease with discharge Q ), elevated arid climates lower humid climates, indicating overwhelming regulation by compared local Critical Zone characteristics such as lithology topography. To understand pattern, parsimonious watershed reactor model was solved bringing together hydrology (storage–discharge relationship) biogeochemical theories traditionally separate disciplines. The derivation steady state solutions lead power law form relationships. illuminates two competing processes that determine solute concentrations: production subsurface chemical weathering reactions, export (or removal) discharge, water flushing capacity dictated vegetation. In other words, watersheds function primarily reactors produce accumulate transporters climates. With space‐for‐time substitution, these results indicate places where dwindles warming climate, will elevate even without human perturbation, threatening quality aquatic ecosystems. Water deterioration therefore should be considered global calculation future risks.

Language: Английский

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