scholarly journals Modeling geogenic and atmospheric nitrogen through the East River Watershed, Colorado Rocky Mountains

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247907
Author(s):  
Taylor Maavara ◽  
Erica R. Siirila-Woodburn ◽  
Fadji Maina ◽  
Reed M. Maxwell ◽  
James E. Sample ◽  
...  
Keyword(s):  
Plant Litter ◽  
Watershed Scale ◽  
Total N ◽  
River Watershed ◽  
Mancos Shale ◽  
N Sources ◽  
East River ◽  
Bedrock Weathering ◽  
Mountainous Watersheds ◽  
Colorado Rocky Mountains

There is a growing understanding of the role that bedrock weathering can play as a source of nitrogen (N) to soils, groundwater and river systems. The significance is particularly apparent in mountainous environments where weathering fluxes can be large. However, our understanding of the relative contributions of rock-derived, or geogenic, N to the total N supply of mountainous watersheds remains poorly understood. In this study, we develop the High-Altitude Nitrogen Suite of Models (HAN-SoMo), a watershed-scale ensemble of process-based models to quantify the relative sources, transformations, and sinks of geogenic and atmospheric N through a mountain watershed. Our study is based in the East River Watershed (ERW) in the Upper Colorado River Basin. The East River is a near-pristine headwater watershed underlain primarily by an N-rich Mancos Shale bedrock, enabling the timing and magnitude of geogenic and atmospheric contributions to watershed scale dissolved N-exports to be quantified. Several calibration scenarios were developed to explore equifinality using >1600 N concentration measurements from streams, groundwater, and vadose zone samples collected over the course of four years across the watershed. When accounting for recycling of N through plant litter turnover, rock weathering accounts for approximately 12% of the annual dissolved N sources to the watershed in the most probable calibration scenario (0–31% in other scenarios), and 21% (0–44% in other scenarios) when considering only “new” N sources (i.e. geogenic and atmospheric). On an annual scale, instream dissolved N elimination, plant turnover (including cattle grazing) and atmospheric deposition are the most important controls on N cycling.

scholarly journals Microbial communities across a hillslope-riparian transect shaped by proximity to the stream, groundwater table, and weathered bedrock

2018 ◽  
Author(s):  
Adi Lavy ◽  
David Geller McGrath ◽  
Paula B. Matheus Carnevali ◽  
Jiamin Wan ◽  
Wenming Dong ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Riparian Zone ◽  
Limited Information ◽  
Metabolic Potential ◽  
Carbon And Nitrogen ◽  
East River ◽  
Mountainous Watersheds ◽  
Geochemical Analyses ◽  
Selenium Reduction ◽  
And Function

AbstractWatersheds are important suppliers of freshwater for human societies. Within mountainous watersheds, microbial communities impact water chemistry and element fluxes as water from precipitation events discharges through soils and underlying weathered rock, yet there is limited information regarding the structure and function of these communities. Within the East River, CO watershed, we conducted a depth-resolved, hillslope to riparian zone transect study to identify factors that control how microorganisms are distributed and their functions. Metagenomic and geochemical analyses indicate that distance from the East River and proximity to groundwater and underlying weathered shale strongly impact microbial community structure and metabolic potential. Riparian zone microbial communities are compositionally distinct from all hillslope communities. Bacteria from phyla lacking isolated representatives consistently increase in abundance with increasing depth, but only in the riparian zone saturated sediments did we find Candidate Phyla Radiation bacteria. Riparian zone microbial communities are functionally differentiated from hillslope communities based on their capacities for carbon and nitrogen fixation and sulfate reduction. Selenium reduction is prominent at depth in weathered shale and saturated riparian zone sediments. We anticipate that the drivers of community composition and metabolic potential identified throughout the studied transect will predict patterns across the larger watershed hillslope system.

Watershed-scale distributions of heavy metals in the hyporheic zones of a heavily polluted Maozhou River watershed, southern China

Chemosphere ◽  
2020 ◽  
Vol 239 ◽  
pp. 124773 ◽  
Author(s):  
Kai Yu ◽  
Yanhua Duan ◽  
Peng Liao ◽  
Lin Xie ◽  
Qianqian Li ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Southern China ◽  
Watershed Scale ◽  
River Watershed ◽  
Hyporheic Zones

scholarly journals Watershed scale response to climate change--East River Basin, Colorado

Fact Sheet ◽  
2012 ◽  
Author(s):  
William A. Battaglin ◽  
Lauren E. Hay ◽  
Steven L. Markstrom
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Watershed Scale ◽  
East River ◽  
Scale Response ◽  
East River Basin

scholarly journals Urochloa ruziziensis responses to sources and doses of urea

2016 ◽  
Vol 20 (5) ◽  
pp. 401-407 ◽  
Author(s):  
João E. S. Lima ◽  
Adriano S. Nascente ◽  
Wilson M. Leandro ◽  
Pedro M. da Silveira
Keyword(s):  
Chlorophyll Content ◽  
Dry Matter ◽  
N Fertilization ◽  
N Losses ◽  
Total N ◽  
Rainy Period ◽  
N Sources ◽  
Use Efficiency ◽  
Tiller Density ◽  
Relative Chlorophyll Content

ABSTRACT The use of products that promote reduction of nitrogen (N) losses from the urea fertilizer can contribute to increasing its use efficiency in forage grasses. This study aimed to evaluate the effects of N sources and doses on the growth of Urochloa ruziziensis. The experiment was carried out in the growing season of 2007/2008 in Santo Antônio de Goiás-GO, in a Brazilian Oxisol. A completely randomized block was used, with four replicates in a factorial scheme, corresponding to two N sources (conventional urea and urea with urease inhibitor) and five N doses (0, 50, 100, 200 and 300 kg ha-1), divided into equal applications in five periods (Nov 14 to Dec 13, Dec 14 to Jan 12, Jan 13 to Feb 11 - rainy season, Mar 24 to Apr 22 and Jul 10 to Aug 08 - dry season). The effects of the treatments were evaluated for: shoot dry matter, tiller density, total N content in the leaves and relative chlorophyll content. N fertilizer sources did not affect the evaluated variables; however, N fertilization allowed linear increases in all variables with higher values during the rainy period. The relative chlorophyll content in U. ruziziensis had positive correlation with its dry matter productivity.

scholarly journals Modeling the Production of Multiple Ecosystem Services from Agricultural and Forest Landscapes in Rhode Island

2013 ◽  
Vol 42 (1) ◽  
pp. 251-274 ◽  
Author(s):  
Tingting Liu ◽  
Nathaniel H. Merrill ◽  
Arthur J. Gold ◽  
Dorothy Q. Kellogg ◽  
Emi Uchida
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Ecosystem Services ◽  
Land Use Change ◽  
Rhode Island ◽  
Land Management ◽  
Management Practices ◽  
Watershed Scale ◽  
River Watershed ◽  
Change Climate

This study spatially quantifies hydrological ecosystem services and the production of ecosystem services at the watershed scale. We also investigate the effects of stressors such as land use change, climate change, and choices in land management practices on production of ecosystem services and their values. We demonstrate the approach in the Beaver River watershed in Rhode Island. Our key finding is that choices in land use and land management practices create tradeoffs across multiple ecosystem services and the extent of these tradeoffs depends considerably on the scenarios and ecosystem services being compared.

Plant litter decomposition and nutrient cycling in north Queensland tropical rain-forest communities of differing successional status

2008 ◽  
Vol 24 (3) ◽  
pp. 317-327 ◽  
Author(s):  
Scott A. Parsons ◽  
Robert A. Congdon
Keyword(s):  
Mass Loss ◽  
Rain Forest ◽  
Tropical Rain Forest ◽  
Nutrient Dynamics ◽  
Plant Litter ◽  
Pioneer Species ◽  
Soil Processes ◽  
Forest Communities ◽  
Forest Species ◽  
Total N

Abstract:Soil processes are essential in enabling forest regeneration in disturbed landscapes. Little is known about whether litterfall from dominating pioneer species in secondary rain forest is functionally equivalent to that of mixed rain-forest litter in terms of contribution to soil processes. This study used the litterbag technique to quantify the decomposition and nutrient dynamics of leaf litter characteristic of three wet tropical forest communities in the Paluma Range National Park, Queensland, Australia over 511 d. These were: undisturbed primary rain forest (mixed rain-forest species), selectively logged secondary rain forest (pioneer Alphitonia petriei) and tall open eucalypt forest (Eucalyptus grandis). Mass loss, total N, total P, K, Ca and Mg dynamics of the decaying leaves were determined, and different mathematical models were used to explain the mass loss data. Rainfall and temperature data were also collected from each site. The leaves of A. petriei and E. grandis both decomposed significantly slower in situ than the mixed rain-forest species (39%, 38% and 29% ash-free dry mass remaining respectively). Nitrogen and phosphorus were immobilized, with 182% N and 134% P remaining in E. grandis, 127% N and 132% P remaining in A. petriei and 168% N and 121% P remaining in the mixed rain-forest species. The initial lignin:P ratio and initial lignin:N ratio exerted significant controls on decomposition rates. The exceptionally slow decomposition of the pioneer species is likely to limit soil processes at disturbed tropical rain-forest sites in Australia.

scholarly journals A Deep-Learning Hybrid-Predictive-Modeling Approach for Estimating Evapotranspiration and Ecosystem Respiration

2020 ◽  
Author(s):  
Jiancong Chen ◽  
Baptiste Dafflon ◽  
Anh Phuong Tran ◽  
Nicola Falco ◽  
Susan S. Hubbard
Keyword(s):  
Climate Change ◽  
Remote Sensing ◽  
Deep Learning ◽  
Predictive Modeling ◽  
Ecosystem Respiration ◽  
Carbon Fluxes ◽  
River Watershed ◽  
Mountainous Regions ◽  
East River ◽  
Physically Based

Abstract. Gradual changes in meteorological forcings (such as temperature and precipitation) are reshaping vulnerable ecosystems, leading to uncertain effects on ecosystem dynamics, including water and carbon fluxes. Estimating evapotranspiration (ET) and ecosystem respiration (RECO) is essential for analyzing the effect of climate change on ecosystem behavior. To obtain a better understanding of these processes, we need to improve our estimation of water and carbon fluxes over space and time, which is difficult within ecosystems where we have only sparse data. In this study, we developed a hybrid predictive modeling approach (HPM) that integrates eddy covariance measurements, physically-based model simulation results, meteorological forcings, and remote sensing datasets to estimate evapotranspiration (ET) and ecosystem respiration (RECO) in high space-time resolution. HPM relies on a deep learning algorithm-long short term memory (LSTM) – as well as direct measurements or outputs from physically-based models. We tested and validated HPM estimation results at sites within various mountainous regions, given their importance for water resources, their vulnerability to climate change, and the recognized difficulties in estimating ET and RECO in mountainous regions. We benchmarked estimates of ET and RECO obtained from the HPM method against measurements made at FLUXNET stations and outputs from the Community Land Model (CLM) at Rocky Mountain SNOTEL stations. At the mountainous East River Watershed site in the Upper Colorado River Basin, we explored how ET and RECO dynamics estimated from the new HPM approach vary with different vegetation and meteorological forcings. The results of this study indicate that HPM is capable of identifying complicated interactions among meteorological forcings, ET, and RECO variables, as well as providing reliable estimation of ET and RECO across relevant spatiotemporal scales. With HPM estimation of ET and RECO at the East River Watershed, we found that abiotic factors of temperature and radiation predominantly explained ET spatial variability; whereas RECO variability was largely controlled by biotic factors, such as vegetation type. In general, our study demonstrated that the HPM approach can circumvent the typical lack of spatiotemporally dense data needed to estimate ET and RECO over space and time, as well as the parametric and structural uncertainty inherent in mechanistic models. While the current limitations of the HPM approach are driven by the temporal and spatial resolution of available datasets (such as NDVI), ongoing advances in remote sensing are expected to further improve accuracy and resolution of ET and RECO estimation using HPM.

scholarly journals Temporal variability in bioassays of ammonia exchange potential in relation to plant and soil nitrogen parameters in intensively managed grassland

2008 ◽  
Vol 5 (4) ◽  
pp. 2749-2772 ◽  
Author(s):  
M. Mattsson ◽  
B. Herrmann ◽  
M. David ◽  
B. Loubet ◽  
M. Riedo ◽  
...  
Keyword(s):  
Leaf Tissue ◽  
Climatic Conditions ◽  
Plant Litter ◽  
Exchange Potential ◽  
Tall Grass ◽  
Total N ◽  
Nh3 Emission ◽  
Intensively Managed ◽  
Ammonia Exchange ◽  
Grass Sward

Abstract. The exchange of ammonia between crop canopies and the atmosphere depends on a range of plant parameters and climatic conditions but little is known about effects of management factors. We have here investigated the ammonia exchange potential of a grass sward dominated by Lolium perenne in response to cutting and fertilization. Tall grass showed a low potential for NH3 emission before cutting. During re-growth after cutting, leaf tissue concentrations of NO3−, NH4+, soluble N and total N increased along with apoplastic NH4+ concentrations. In contrast, apoplastic pH decreased resulting in largely unaltered NH3 emission potential. A high potential for NH3 emission was shown by the plant litter. Fertilization with 100 kg N ha−1 one week after cutting caused the apoplastic NH4+ concentration of the newly emerging leaves to increase dramatically. The apoplastic NH4+ concentration peaked the day after the fertiliser was applied and thereafter decreased over the following 10 days until reaching the same level as before fertilisation. A positive correlation was found between NH4+ concentrations in leaf apoplast, bulk tissue and litter throughout the experimental period. Leaf soluble N was negatively correlated with apoplastic NH4+ concentration whereas total N was weakly correlated with NH4+ concentrations in leaf tissue and soil.

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