Article
Engineering, Civil
Ioannis Matiatos, Christian Moeck, Yuliya Vystavna, Hannu Marttila, Natalie Orlowski, Soren Jessen, Jaivime Evaristo, Mathieu Sebilo, Gerbrand Koren, Elias Dimitriou, Sasha Mueller, Yiannis Panagopoulos, Michael P. Stockinger
Summary: There are challenges in simulating water flow and quality at a catchment-scale, particularly when it comes to tracking nitrate ions. Most models focus on specific compartments of the watershed and fail to consider catchment internal processes. Incorporating nitrate isotopes into these models can enhance their accuracy.
JOURNAL OF HYDROLOGY
(2023)
Article
Forestry
Lars Lundin, Torbjorn Nilsson
Summary: Forest fertilization with nitrogen can have adverse effects such as acidification and nitrate leaching. The study found high excess outflow of nitrogen, calcium, and magnesium, with nitrate dominating total nitrogen. Effects on pH were limited.
FOREST ECOLOGY AND MANAGEMENT
(2021)
Article
Engineering, Environmental
Seung-Hee Kim, Dong-Hun Lee, Min-Seob Kim, Han-Pil Rhee, Jin Hur, Kyung-Hoon Shin
Summary: In this study, an integrated framework was validated to effectively manage nitrate loading in complex river systems through quantitative estimation of nitrate sources. The isotopic compositions of nitrates showed different ranges among land-use types, reflecting different nitrate sources within watersheds. Hydrological conditions, such as water discharge, partially controlled total nitrate loads. Sewage transport near urban boundaries showed unique enhancement and increased total nitrate load in downstream areas. The isotopic and model-based nitrate fluxes showed good correlation for urban sources but poor correlation for agriculture-dominated land use.
Article
Environmental Sciences
Kevin A. Ryan, Thomas Adler, Ann Chalmers, Julia Perdrial, James B. Shanley, Aron Stubbins
Summary: The study found that concentrations of DOC and TDN in trees decreased exponentially with increasing precipitation, while stream concentrations increased with streamflow. In most cases, the fluxes of DOC and TDN from trees via throughfall and stemflow greatly exceeded stream fluxes, but the imbalance narrowed for larger storm events. The research highlights the differing impacts of event size on tree versus stream fluxes, which have important implications for forested ecosystems as hydrological events increase in intensity and frequency due to climate change.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2021)
Article
Environmental Sciences
Konstantina Pyrgaki, Efstratios Kelepertzis, Ariadne Argyraki, Pascal Boeckx, Fotini Botsou, Emmanuel Dassenakis
Summary: A coupled methodology of nitrogen isotopes, hydrogeochemical characterization, multivariate statistical analysis, and SIAR Bayesian modeling was used to identify the sources of NO3- and N transformation processes in three alluvial aquifers in central Greece. The study found that the groundwater in these aquifers is contaminated with hexavalent chromium and nitrate. The dominant nitrogen transformation process was nitrification, which was influenced by domestic sewage and N-bearing fertilizers. Multivariate statistical analysis revealed that salinization, silicate dissolution, and groundwater contamination due to fertilizer use were the main processes in the study areas.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Environmental Sciences
Juan Antonio Torres-Martinez, Abrahan Mora, Jurgen Mahlknecht, Luis W. Daessle, Pabel A. Cervantes-Aviles, Rogelio Ledesma-Ruiz
Summary: The study identified sources and transformations of nitrate in groundwater in Comarca Lagunera, northern Mexico. High nitrate concentrations were found in over 32% of sites, primarily sourced from concentrated animal-feeding operations' manure and urban sewage. Biogeochemical transformations varied along groundwater flow paths.
ENVIRONMENTAL POLLUTION
(2021)
Article
Environmental Studies
Devika Nair, Ken G. Evans, Sean M. Bellairs
Summary: This study aimed to analyze the impact of rainfall events on the upper catchment and their effect on downstream geomorphology using the HEC-HMS model. The research showed that the landform gradually attains stability over time, as indicated by the decreasing sediment spikes following rainfall-runoff events. The study also predicted the sediment yield based on simulated rainfall trends over a projected 50-year period.
Article
Environmental Sciences
Sri Adiyanti, Yasuyuki Maruya, Bradley D. Eyre, Perrine Mangion, Jeffrey Turner, Mathew R. Hipsey
Summary: This study demonstrates the successful allocation of nitrogen sources during wet periods by measuring the dual stable isotopes of nitrate in conjunction with routine nitrogen concentration data. The main land use exporting nitrogen during high rainfall periods was wetland, with reduced uncertainty in calculated rates when using dual isotopes.
WATER RESOURCES RESEARCH
(2022)
Article
Plant Sciences
Yi Hu, Robert D. Guy, Raju Y. Soolanayakanahally
Summary: Nitrogen isotope discrimination (ΔN-15) can be used as an indicator of nitrogen use in plants. In this study, a simple isotope mass balance (IMB) model was used to analyze the nitrogen use efficiency of different canola lines. The results showed that commercial hybrids had a higher capability to utilize ammonium as their sole nitrogen source compared to open-pollinated lines.
FRONTIERS IN PLANT SCIENCE
(2022)
Article
Engineering, Civil
Xiangqian Zhou, Seifeddine Jomaa, Xiaoqiang Yang, Ralf Merz, Yanping Wang, Michael Rode
Summary: Like many other regions in central Europe, Germany experienced summer droughts from 2015 to 2018, which significantly affected the river nitrate concentrations. In this study, a model was used to investigate the causal relations and spatial trends of nitrate concentrations in the Bode catchment. The model successfully captured the spatially contrasting trends of nitrate concentrations and revealed that droughts led to a decrease in nitrate concentrations due to reduced terrestrial export loading and increased in-stream retention efficiency. This study provides insights into water quality responses to future climate change.
JOURNAL OF HYDROLOGY
(2022)
Article
Engineering, Civil
Jun Zhang, Rongfei Wei, Teklit Zerizghi, Ziteng Wang, Meng Cui, Chenjun Du, Fujun Yue, Qingjun Guo
Summary: This study investigated the spatiotemporal variations of nitrate sources and transformations in the Yangtze River, and compared the current measurements after environmental regulations with historical records in 2006. The results showed that the dominant nitrate source changed after the implementation of environmental regulations, but the major nitrate transformations remained unaffected. This study provided significant information for adjusting and formulating new policies to control nitrate pollution.
JOURNAL OF HYDROLOGY
(2023)
Article
Environmental Sciences
Katharina Blaurock, Phil Garthen, Maria P. da Silva, Burkhard Beudert, Benjamin S. Gilfedder, Jan H. Fleckenstein, Stefan Peiffer, Oliver J. Lechtenfeld, Luisa Hopp
Summary: The transport of dissolved organic carbon (DOC) from soils to inland waters is crucial for the global carbon cycle. The interplay between microtopography and groundwater level dynamics plays a significant role in DOC export.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Liang Yu, Joachim C. Rozemeijer, Hans Peter Broers, Boris M. van Breukelen, Jack J. Middelburg, Maarten Ouboter, Ype van der Velde
Summary: High-frequency monitoring of nitrogen and phosphorus dynamics in a low-lying urban polder in Amsterdam revealed temporal variations at different scales, with electrical conductivity influenced by groundwater-seepage and runoff mixture, and nutrient fluxes regulated by primary production and iron transformations.
HYDROLOGY AND EARTH SYSTEM SCIENCES
(2021)
Article
Water Resources
J. I. Lopez-Moreno, I. Granados, A. Ceballos-Barbancho, E. Moran-Tejeda, J. Revuelto, E. Alonso-Gonzalez, S. Gascoin, J. Herrero, C. Deschamps-Berger, J. Latron
Summary: For the first time, this study investigated the streamflow and streamwater isotopes during snow accumulation and melting periods in two snow seasons. The results showed that the isotopic content of the streamwater gradually became depleted, and higher snowfall led to lower isotopic values. The interannual variability of isotopic signature during snowmelt posed a challenge in establishing reference values for hydrograph separation. The study also indicated the importance of alpine aquifers and piston flow in explaining the hydrological functioning of the catchment.
JOURNAL OF HYDROLOGY-REGIONAL STUDIES
(2023)
Article
Environmental Sciences
Shi-Qi Xu, Xue-Yan Liu, Zhong-Cong Sun, Chao-Chen Hu, Wolfgang Wanek, Keisuke Koba
Summary: The study investigated soil nitrogen transformations in 11 forests with different nitrogen deposition levels, finding that depolymerization, mineralization, and nitrification of soil nitrogen increased while losses decreased with increasing nitrogen deposition. The contribution of denitrification to total nitrate losses also increased with nitrogen deposition, providing new insights into soil nitrogen dynamics and forest nitrogen cycles under different deposition regimes.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Article
Engineering, Environmental
Caroline E. Pierce, Olha S. Furman, Sarah L. Nicholas, Jill Coleman Wasik, Caitlin M. Gionfriddo, Ann M. Wymore, Stephen D. Sebestyen, Randall K. Kolka, Carl P. J. Mitchell, Natalie A. Griffiths, Dwayne A. Elias, Edward A. Nater, Brandy M. Toner
Summary: We investigated the composition and spatial correlation of sulfur and mercury pools in peatland soil profiles. Our findings suggest that organic sulfur species play an important role in mercury methylation processes.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Water Resources
James B. Shanley, Ann T. Chalmers, Jon C. Denner, Stewart F. Clark, Stephen D. Sebestyen, Serena Matt, Thor E. Smith
Summary: The Sleepers River Research Watershed is a research area in Vermont, USA, established in 1957 by the U.S. Department of Agriculture. The U.S. Geological Survey currently operates and expands the hydrological foundation of the area. This data note introduces five freely available data releases in the watershed.
HYDROLOGICAL PROCESSES
(2022)
Article
Geochemistry & Geophysics
Xinbo Liu, Li Guo, Xihong Cui, John R. Butnor, Elizabeth W. Boyer, Dedi Yang, Jin Chen, Bihang Fan
Summary: In this study, ground-penetrating radar (GPR) was used to noninvasively characterize root water content (RWC) of coarse roots. An automatic GPR data processing framework was proposed to identify root reflections and extract waveform parameters to determine RWC. The developed models achieved good performance in estimating RWC with high accuracy, especially when applied to 2-GHz data.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Ecology
Sarah J. Shelley, Deanne J. Brice, Colleen M. Iversen, Randy K. Kolka, Stephen D. Sebestyen, Natalie A. Griffiths
Summary: Bryophytes play a crucial role in carbon accumulation in peatland ecosystems. Intrinsic and extrinsic factors both influence moss decomposition, with intrinsic characteristics driving early decay stages and extrinsic factors becoming more important over time. Longer-term studies are needed to fully understand the complexities of moss decay and inform carbon and climate models.
Article
Ecology
Colleen M. Iversen, John Latimer, Deanne J. Brice, Joanne Childs, Holly M. Vander Stel, Camille E. Defrenne, Jake Graham, Natalie A. Griffiths, Avni Malhotra, Richard J. Norby, Keith C. Oleheiser, Jana R. Phillips, Verity G. Salmon, Stephen D. Sebestyen, Xiaojuan Yang, Paul J. Hanson
Summary: Warming is found to exponentially increase plant-available ammonium and phosphate in a peatland ecosystem, with no effect from elevated CO2 levels. The dynamics of nutrient availability are influenced by peat depth and microtopography. Future predictions of peatland nutrient availability should take into account dynamic changes in nutrient acquisition by plants and microbes, as well as peat depth and microtopography.
Article
Water Resources
Veronica M. Porter, James B. Shanley, Stephen D. Sebestyen, Fengjing Liu
Summary: Previous studies on concentration-discharge (C-Q) relationships have focused on short-term or low-temporal resolution data, providing limited insight on catchment response over time or to climate change. In this study, using 15 solutes data from 1992 to 2015 at Sleepers River Research Watershed, the researchers compared C-Q relationships over decades, years, and seasons. They applied end-member mixing analysis (EMMA) to identify solute sources and flow path routing. The results showed that shifting mixing proportions of near-surface runoff (NSR), riparian groundwater, and hillslope hollow groundwater accounted for the temporal variability of conservative solutes in streamflow. The researchers also found that the b-coefficient of the C-Q relation decreased significantly with an increase in the groundwater to NSR concentration ratio for conservative solutes. Additionally, the strength of dilution or flushing was stronger during the snowmelt period compared to other seasons. These findings provide more tools for the interpretation of catchment processes and responses to climate change.
HYDROLOGICAL PROCESSES
(2022)
Article
Water Resources
Elizabeth W. Boyer, Max A. Moritz, Michael G. Brown
Summary: This study investigates the changes in the chemical composition of deionized water samples exposed to smoke. The results show that smoke inputs can lead to increased acidity, higher levels of organic matter, and an elevated content of inorganic nitrogen species in the water samples. However, the findings may not directly apply to natural waters, as the response may vary depending on the ionic strength and acid-neutralizing capacity of the water.
HYDROLOGICAL PROCESSES
(2022)
Article
Environmental Sciences
Colin P. R. McCarter, Susan L. Eggert, Stephen D. Sebestyen, Randall K. Kolka, Carl P. J. Mitchell
Summary: This study compared the effects of different forest management practices on the migration of mercury and related substances in runoff, and assessed the mercury concentrations in downstream peat soil. The study found that the removal of residual biomass significantly increased solute yields, but did not necessarily stimulate mercury methylation or accumulation in invertebrates.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2022)
Article
Forestry
Anna B. Stockstad, Robert A. Slesak, Alan J. Toczydlowski, Charles R. Blinn, Randall K. Kolka, Stephen D. Sebestyen
Summary: This study examined the responses of forest soils to simulated future climate conditions including reduced precipitation and snow removal. The results showed that the treatments had limited effects on soil respiration and nitrogen concentrations, likely due to the minimal impacts on soil moisture content and temperature. Soil drainage class was only a significant factor during the spring thaw period, with poorly drained plots having lower respiration rates compared to well-drained plots. Laboratory incubation experiments further confirmed the effects of drainage class and moisture content on soil respiration. Overall, the combined effects of reduced summer and winter precipitation on soil respiration and nitrogen dynamics were limited in the studied conditions.
Article
Environmental Sciences
Kevin A. Ryan, Thomas Adler, Ann T. Chalmers, Julia Perdrial, Stephen Sebestyen, James B. Shanley, Aron Stubbins
Summary: Tree-derived dissolved organic matter (DOM) is an important carbon flux in forested watersheds. This study assessed the optical properties and factors controlling DOM quality in a temperate deciduous forest. The results showed that throughfall and stemflow had higher concentrations of dissolved organic carbon and calcium than rainwater. A multiway model was developed to characterize DOM optical properties, and different tree species and seasons were found to influence DOM quality.
Article
Forestry
Anna B. Stockstad, Robert A. Slesak, Alan J. Toczydlowski, Charles R. Blinn, Randall K. Kolka, Stephen D. Sebestyen
Summary: Climate change affects precipitation patterns, including decreased snow accumulation and summer rainfall, in northern latitudes. These changes have implications for soil physical properties, specifically soil strength. Findings from this study show that snow removal leads to lower soil temperature, deeper frost penetration, while reduced rainfall has inconsistent effects on soil water content and strength. Drainage class and air freezing index can be used to predict the availability of frozen soil for forest management activities.
FOREST ECOLOGY AND MANAGEMENT
(2022)
Article
Environmental Sciences
Daniel Liptzin, Jens Boy, John L. Campbell, Nicholas Clarke, Jean-Paul Laclau, Roberto Godoy, Sherri L. Johnson, Klaus Kaiser, Gene E. Likens, Gunilla Pihl Karlsson, Daniel Markewitz, Michela Rogora, Stephen D. Sebestyen, James B. Shanley, Elena Vanguelova, Arne Verstraeten, Wolfgang Wilcke, Fred Worrall, William H. McDowell
Summary: Atmospheric deposition of dissolved organic carbon (DOC) plays an important role in the carbon cycle of terrestrial ecosystems. The concentration of DOC and precipitation are the key factors influencing the deposition of DOC, with higher concentrations observed in tropical regions. Seasonal variations in DOC concentration were observed, with higher concentrations during the growing season in temperate regions and during the dry season in tropical regions. Long-term data sets showed significant declines in DOC concentration, which may be attributed to decreases in anthropogenic emissions.
GLOBAL BIOGEOCHEMICAL CYCLES
(2022)
Article
Engineering, Environmental
Colin P. R. McCarter, Stephen D. Sebestyen, Jill K. Coleman Wasik, Coleman Wasik, Daniel R. Engstrom, Randall K. Kolka, Jeff D. Jeremiason, Edward B. Swain, Bruce A. Monson, Brian A. Branfireun, Steven J. Balogh, Edward A. Nater, Susan L. Eggert, Paris Ning, Carl P. J. Mitchell
Summary: This study presents empirical evidence of the relationship between declining sulfate deposition and changes in mercury methylation and water quality in peatlands. The results show that when sulfate additions stopped, the export of methylmercury quickly returned to baseline levels in the peatland-dominated catchment.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Civil
Mariel W. Jones, Stephen D. Sebestyen, Salli F. Dymond, G. H. Crystal Ng, Xue Feng
Summary: The relationship between snowmelt and spring streamflow is changing under warming temperatures and diminishing snowpack. The hydrologic connectivity across catchment landscape elements, such as snowpack and surface wetlands, plays a critical role in controlling the routing of snowmelt to streams. The effects of soil frost on the movement of water from a snowpack to a stream are not fully understood.
JOURNAL OF HYDROLOGY
(2023)
Article
Geochemistry & Geophysics
Juliana D. ' Andrilli, Carlos M. Romero, Phoebe Zito, David C. Podgorski, Robert A. Payn, Stephen D. Sebestyen, Andrew R. Zimmerman, Fernando L. Rosario -Ortiz
Summary: Patterns in Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) data provide insights into the characteristics of organic matter influenced by natural processes. This study reevaluates the molecular lability boundary (MLB) approach to assess organic matter lability, incorporating new data and considering different experimental conditions. The findings suggest the need to reframe the MLB approach to include lability indices for biotic, thermal, and photochemical processes, and provide a broader perspective on ecosystem form and function trends.
ORGANIC GEOCHEMISTRY
(2023)