Опубликована: Янв. 1, 2024
Язык: Английский
Water Resources Research, Год журнала: 2025, Номер 61(4)
Опубликована: Март 29, 2025
Abstract Headwater catchments have strong impacts on downstream waterways, near‐shore ecosystems, and the quality of water available for growing human populations. Thus, understanding how solutes are exported through these upland landscapes is critically important. A body literature highlights interaction topography, climate, critical zone structure as a key control streamflow chemical export. However, more focused work needed to pinpoint variability in subsurface across lithologically complex regions signals at catchment outlets. Here, we aim better understand lithology zones modulate response solute export patterns two central coastal California headwater that similar vegetation, climate but different lithologies. We monitored collected surface samples outlets dissolved major ions organic carbon (DOC) consecutive years. The with mélange bedrock displayed much flashier hydrologic behavior 7.8 times higher peak flow values 1.9 mean event concentrations DOC, suggesting shorter shallower paths likely arise from bedrock. Despite distinct DOC export, ion were broadly chemostatic, which may be driven by rapid reactions both catchments. Our contributes building an integrated subtle differences can profound routed
Язык: Английский
Процитировано
1
The Science of The Total Environment, Год журнала: 2024, Номер 940, С. 173677 - 173677
Опубликована: Май 31, 2024
Eutrophication is a significant environmental problem caused by nutrient loads from both point and non-point sources. Weather variables, particularly precipitation, affect the concentration of nutrients in water bodies, those sources, two contrasting ways. Heavy precipitation causes surface runoff which transports pollutants to rivers increases concentration. Conversely, increased river flow can dilute concentration, lowering it. This study investigates impact extreme prolonged after dry period on total phosphorus Moehne Erft Germany, given projected increase frequency events long drought periods due climate change. The comprises parts: selecting weather days 2001 2021 comparing observed Total Phosphorus concentrations with estimated derived Generalized Additive Models linear regression based discharge-concentration relationship. Changes TP response continuous were also studied. Our results showed that during wet post-dry rainfall events, consistently surpassed expected values, underscoring profound influence intense mobilization. However, we be non-unidirectional. work distinguished three key innovations: 1) addressing limitations studying effects quality limited temporal resolution, 2) incorporating non-linear modeling approaches for relationships, 3) performing comprehensive analysis spatial patterns varying patterns.
Язык: Английский
Процитировано
8
Water Research, Год журнала: 2024, Номер 264, С. 122108 - 122108
Опубликована: Июль 25, 2024
The profound influence of climate change on the hydrological cycle raises concerns about its potential impacts water quality, particularly in agricultural catchments. Here, we analysed 200 storm events monitored for nitrate and total phosphorus (TP) at sub-hourly intervals from 2016 to 2023 Kervidy-Naizin catchment (north-western France). Using Extreme Value theory, identified with extreme concentrations compared their hydroclimatic characteristics those non-extreme events. We hypothesised that concentration occurred under conditions, which are projected become more frequent future. showed dilution patterns nitrate, decreasing by up 41 %, accretion TP, increasing 1400 % Hydroclimatic conditions during were characterised high rainfall intensities low antecedent discharge, but no particular mean discharge. During events, concentration-discharge relationships exhibited primarily clockwise hysteresis, whereas TP displayed an equal mix anticlockwise loops. In contrast, hysteresis weak TP. interpreted these dynamics controls as result infiltration-excess overland flow diluting nitrate-rich groundwater exporting large amounts intensive following droughts, while fluctuations riparian zone streambed remobilization control nutrient exports Given frequency intensity extremes, such retrospective analyses can provide valuable insights into future streams draining
Язык: Английский
Процитировано
7
Water, Год журнала: 2024, Номер 16(18), С. 2628 - 2628
Опубликована: Сен. 16, 2024
This study investigates the long-term trends (1992–2022) of nitrogen and phosphorus loadings exported by River Po to Adriatic Sea, better analyse how changes in hydrology are affecting timing magnitude river nutrient loads. We used 30 years monitoring data order (a) identify main temporal patterns their interactions at a decadal, annual seasonal scale, (b) estimate precipitation effects on load formation evaluate whether which extent hydrological regime affects export across (c) monthly scale transport dynamic N P chemical species (hydrological vs. biogeochemical control). The analysis shows general decrease both loadings, but different between elements species, as well undergoing variations. found statistically significant relationships loads, demonstrates that drive intra- interannual time scales considered this study. Precipitation-induced trigger deliveries sea, peaking spring autumn. is mainly concentrated summer dry period, while total diminishes mismatch results variable molar N:P ratios within year. extreme drought flood events, along with progressive snowmelt contribution water fluxes, expected exacerbate variability turn perturbate biodiversity, food webs trophic state Northern Sea.
Язык: Английский
Процитировано
4
Chaos Solitons & Fractals, Год журнала: 2025, Номер 195, С. 116167 - 116167
Опубликована: Март 14, 2025
Язык: Английский
Процитировано
0
Hydrological Processes, Год журнала: 2025, Номер 39(5)
Опубликована: Май 1, 2025
ABSTRACT Machine‐learning models have been surprisingly successful at predicting stream solute concentrations, even for solutes without dedicated sensors. It would be extremely valuable if these could predict concentrations in streams beyond the one which they were trained. We assessed generalisability of random forest by training them or more and testing another. Models made using grab sample sensor data from 10 New Hampshire rivers. As observed previous studies, trained capable accurately that stream. However, on produced inaccurate predictions other streams, with exception measured sensors (i.e., nitrate dissolved organic carbon). Using multiple watersheds improved model results, but performance was still worse than mean dataset (Nash–Sutcliffe Efficiency < 0). Our results demonstrate machine‐learning thus far reliably only where trained, as differences concentration patterns sensor‐solute relationships limit their broader applicability.
Язык: Английский
Процитировано
0
Geophysical Research Letters, Год журнала: 2024, Номер 51(10)
Опубликована: Май 23, 2024
Abstract The mechanisms driving catchment nitrogen storage and release operate at multiple spatiotemporal scales. Consequently, analyses grounded in different observational timescales can yield discrepant interpretations of underlying mechanisms. To assess the consistency nitrate export patterns between event‐ inter‐annual scales, we evaluated years high‐frequency observations concentrations (C) discharge (Q) including 3,480 discrete events from 28 dominantly agricultural catchments. We observed consistent often drastic divergence long‐term median event‐specific C‐Q patterns. Most catchments showed enrichment (positive slope), but were, on average, more chemostatic (close‐to‐zero slopes). slope variability was high for small decreased with event magnitude, approaching during largest storms, yielding compelling evidence against source limitation. conclude that temporal scales magnitudes are controlled by processes, therefore embedding complementary information.
Язык: Английский
Процитировано
3
Hydrological Processes, Год журнала: 2024, Номер 38(6)
Опубликована: Июнь 1, 2024
Abstract Understanding controls on solute export to streams is challenging because heterogeneous catchments can respond uniquely drivers of environmental change. To understand general patterns, we used a large‐scale inductive approach evaluate concentration–discharge (C–Q) metrics across spanning broad range catchment attributes and hydroclimatic drivers. We leveraged paired C–Q data for 11 solutes from CAMELS‐Chem, database built upon an existing dataset relatively undisturbed the contiguous USA. Because relationships with Q thresholds reflect shift in dynamics are poorly characterized diverse catchments, analysed using Bayesian segmented regression quantify relationship. Threshold responses were rare, representing only 12% relationships, 56% which occurred predominantly sourced bedrock. Further, dominated by one or two patterns that reflected vertical solute–source distributions. Specifically, bedrock had diluting 43%–70% soils more enrichment 35%–51% catchments. also linked patterns. The generally weak despite diversity attribute types considered. However, central USA typically drove most divergent behaviour solutes. illustrate how our generated new hypotheses be tested at discrete, representative deductive approaches better processes underlying Finally, given these long‐term minimally disturbed findings as benchmarks change
Язык: Английский
Процитировано
3
Water Resources Research, Год журнала: 2025, Номер 61(3)
Опубликована: Март 1, 2025
Abstract Hydrologic regimes are affecting terrestrial carbon transformation, chemical weathering and lateral transport. However, its impacts on dissolved export patterns remains elusive. In this study, we collected a 2‐year high‐frequency inorganic (DIC) organic (DOC) dataset, namely wet year (Rainfall = 1,158 mm) dry 603 mm). The results showed that drought led to significant decrease in concentration discharge during the monitoring period. During non‐storm periods, DIC DOC shifted from dilution chemostatic enrichment years, respectively. were reversed storm periods. dominated by chemostatic, respectively, while both year. Structural equation models revealed aridity index temperature may affect patterns. We further classified events into three major types conceptualized catchment‐scale transport mechanisms for carbon. Dry‐AMCs result behavior, whereas Wet‐AMCs behavior due increased hydrological connectivity. third type corresponds extreme events, where larger overland flow often but behavior. These findings reveal predominant role of altering decreasing concentrations fluxes modifying
Язык: Английский
Процитировано
0
Journal of Geophysical Research Biogeosciences, Год журнала: 2025, Номер 130(4)
Опубликована: Март 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.
Язык: Английский
Процитировано
0