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274 results for “nitrogen deposition”
Umbilicaria Mammulata and Nitrogen Deposition at Harvard Forest 2006
Atmospheric N has quadrupled due to anthropogenic inputs and is projected to double again by 2050. The lichen Umbilicaria mammulata relies primarily on atmospheric deposition for nutrients, including N. Much of this species’ geographic distribution coincides with the N deposition gradient in the eastern US. We were interested in the potential impacts of N deposition on this species under realistic field conditions. Lichens were collected at six sites, ranging from Maine (low deposition) to West Virginia (high deposition). Thalli were analyzed for %C, %N, C:N, specific thallus weight (a measure of thickness), chlorophyll content, and chlorophyll fluorescence. Using stepwise regression we identified the most predictive model(s) using N deposition, environmental variables, and climate to predict differences in lichen ecophysiology and biochemistry across the gradient. While N deposition was important in predicting some responses, the model that best predicted %N in lichen only included mean minimum temperature, mean annual precipitation, and substrate slope. In controlled experiments at Grandfather Mountain (Linville NC) lichens were fertilized in situ with N to mimic deposition projected for 2050. There were no significant differences between control and fertilized thalli for any response variables, but differences did exist among sites. The results of this study highlight the complexities associated with sampling along a gradient of one factor in a multivariate environment.
Nitrogen Deposition and Pitcher Plant Morphology in Massachusetts and Vermont 1998-1999
Atmospheric transport and deposition of nutrients, especially nitrogen, is a global environmental problem with well-documented consequences for ecosystem dynamics. However, monitoring nitrogen deposition is relatively expensive, monitoring stations are widely spaced, and estimates and predicted impacts of nitrogen deposition are currently derived from spatial modeling and interpolation of limited data. Bogs are nutrient-poor ecosystems that are especially sensitive to increasing nutrient input, and carnivorous plants, which are characteristic of these widespread ecosystem types, may be especially sensitive indicators of N deposition. Botanical carnivory is thought to have evolved in nutrient-poor and well-lit habitats such as bogs because the marginal benefits accruing from carnivory exceed the marginal photosynthetic costs associated with the maintenance of carnivorous organs. However, the production of carnivorous organs can be a phenotypically plastic trait. The northern pitcher plant, Sarracenia purpurea, produces leaves specialized for prey capture and nutrient uptake (pitchers) and leaves that are more efficient at photosynthesis (phyllodia). We hypothesized that relative allocation to these two types of leaves reflects ambient nitrogen availability. We manipulated nutrient availability to plants with leaf enrichment and whole-plot fertilization experiments. Increased nitrogen, but not phosphorus, reduced production of pitchers relative to phyllodia; this result provided empirical support for the cost–benefit model of the evolution of botanical carnivory. Because this phenotypic shift in leaf production occurs in ecological time, our results suggest that S. purpurea could be a reliable and inexpensive biological indicator of nitrogen deposition rates. This suggestion is supported by field observations across a geographic gradient of nitrogen deposition.
Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Net Primary Production Quadrat Data at the Sevilleta National Wildlife Refuge, New Mexico
Humans are creating significant global environmental change, including shifts in climate, increased nitrogen (N) deposition, and the facilitation of species invasions. A multi-factorial field experiment is being performed in an arid grassland within the Sevilleta National Wildlife Refuge (NWR) to simulate increased nighttime temperature, higher N deposition, and heightened El Niño frequency (which increases winter precipitation by an average of 50%). The purpose of the experiment is to better understand the potential effects of environmental change on grassland community composition and the growth of introduced creosote seeds and seedlings. The focus is on the response of three dominant species, all of which are near their range margins and thus may be particularly susceptible to environmental change. It is hypothesized that warmer summer temperatures and increased evaporation will favor growth of black grama (Bouteloua eriopoda), a desert grass, but that increased winter precipitation and/or available nitrogen will favor the growth of blue grama (Bouteloua gracilis), a shortgrass prairie species. Furthermore, it is thought that the growth and survival of introduced creosote (Larrea tridentata) seeds and seedlings will be promoted by heightened winter precipitation, N addition, and warmer nighttime temperatures. Treatment effects on limiting resources (soil moisture, nitrogen mineralization), species growth (photosynthetic rates, creosote shoot elongation), species abundance, and net primary production (NPP) are all being measured to determine the interactive effects of key global change drivers on arid grassland plant community dynamics. To measure above-ground NPP (i.e., the change in plant biomass, represented by stems, flowers, fruit and foliage, over time), the vegetation variables in this dataset, including species composition and the cover and height of individuals, are sampled twice yearly (spring and fall) at permanent 1m x 1m plots. The data from these pl
Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Seasonal Biomass and Seasonal and Annual NPP at the Sevilleta National Wildlife Refuge, New Mexico
Begun in winter 2006, this long-term study at the Sevilleta LTER examines how heightened winter precipitation, N addition, and warmer nighttime temperatures affect above-ground biomass production (ANPP) in a mixed desert-grassland. Net primary production is a fundamental ecological variable that quantifies rates of carbon consumption and fixation. Estimates of NPP are important in understanding energy flow at a community level as well as spatial and temporal responses to a range of ecological processes. While measures of both below- and above-ground biomass are important in estimating total NPP, this study focuses on above-ground net primary production (ANPP). Above-ground net primary production is the change in plant biomass, including loss to death and decomposition, over a given period of time. Volumetric measurements are made using vegetation data from permanent plots (SEV176, "Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Net Primary Production Quadrat Data") and regressions correlating species biomass and volume constructed using seasonal harvest weights from SEV157, "Net Primary Productivity (NPP) Weight Data."
Modeled dry deposition flux of nitrogen (NO) in central Arizona, USA (1998)
The role of urban vegetation on NOx-derived dry deposition fluxes was investigated for the arid Phoenix (Arizona, USA) metropolitan area using the Community Multiscale Air Quality Model (CMAQ) (9-13 June 1998). A new land cover classification and updated land cover data were introduced in the model to account for spatial extent and heterogeneity of urban land cover. Adjustments were made in the deposition velocity calculations to consider the adaptation of local plants to the environmental conditions of Central Arizona. According to the simulations 25 % of the NOx derived dry deposition fluxes in the urban area were deposited on vegetation. When urban vegetation was excluded from the simulations NO2 deposition was reduced by 57 % because of the significantly lower deposition velocities of impervious compared to vegetated surfaces; nitric acid deposition was relatively unchanged. Using a diagnostic model with input data from urban air quality monitoring sites, hourly NO and NO2 dry N deposition fluxes were simulated for the entire year 1998 to ~6 kg ha-1 yr-1. Dry deposition declined during the summer months, due to lower pollutant concentrations and temperature-induced closure of the plant stomata during afternoon hours.
Modeled dry deposition flux of nitrogen dioxide (NO2) in central Arizona, USA (1998)
The role of urban vegetation on NOx-derived dry deposition fluxes was investigated for the arid Phoenix (Arizona, USA) metropolitan area using the Community Multiscale Air Quality Model (CMAQ) (9-13 June 1998). A new land cover classification and updated land cover data were introduced in the model to account for spatial extent and heterogeneity of urban land cover. Adjustments were made in the deposition velocity calculations to consider the adaptation of local plants to the environmental conditions of Central Arizona. According to the simulations 25 % of the NOx derived dry deposition fluxes in the urban area were deposited on vegetation. When urban vegetation was excluded from the simulations NO2 deposition was reduced by 57 % because of the significantly lower deposition velocities of impervious compared to vegetated surfaces; nitric acid deposition was relatively unchanged. Using a diagnostic model with input data from urban air quality monitoring sites, hourly NO and NO2 dry N deposition fluxes were simulated for the entire year 1998 to ~6 kg ha-1 yr-1. Dry deposition declined during the summer months, due to lower pollutant concentrations and temperature-induced closure of the plant stomata during afternoon hours.
Modeled dry deposition flux of nitrogen (HNO3) in central Arizona, USA (1998)
The role of urban vegetation on NOx-derived dry deposition fluxes was investigated for the arid Phoenix (Arizona, USA) metropolitan area using the Community Multiscale Air Quality Model (CMAQ) (9-13 June 1998). A new land cover classification and updated land cover data were introduced in the model to account for spatial extent and heterogeneity of urban land cover. Adjustments were made in the deposition velocity calculations to consider the adaptation of local plants to the environmental conditions of Central Arizona. According to the simulations 25 % of the NOx derived dry deposition fluxes in the urban area were deposited on vegetation. When urban vegetation was excluded from the simulations NO2 deposition was reduced by 57 % because of the significantly lower deposition velocities of impervious compared to vegetated surfaces; nitric acid deposition was relatively unchanged. Using a diagnostic model with input data from urban air quality monitoring sites, hourly NO and NO2 dry N deposition fluxes were simulated for the entire year 1998 to ~6 kg ha-1 yr-1. Dry deposition declined during the summer months, due to lower pollutant concentrations and temperature-induced closure of the plant stomata during afternoon hours.
Modeled dry deposition flux of total nitrogen in central Arizona, USA (1998)
The role of urban vegetation on NOx-derived dry deposition fluxes was investigated for the arid Phoenix (Arizona, USA) metropolitan area using the Community Multiscale Air Quality Model (CMAQ) (9-13 June 1998). A new land cover classification and updated land cover data were introduced in the model to account for spatial extent and heterogeneity of urban land cover. Adjustments were made in the deposition velocity calculations to consider the adaptation of local plants to the environmental conditions of Central Arizona. According to the simulations 25 % of the NOx derived dry deposition fluxes in the urban area were deposited on vegetation. When urban vegetation was excluded from the simulations NO2 deposition was reduced by 57 % because of the significantly lower deposition velocities of impervious compared to vegetated surfaces; nitric acid deposition was relatively unchanged. Using a diagnostic model with input data from urban air quality monitoring sites, hourly NO and NO2 dry N deposition fluxes were simulated for the entire year 1998 to ~6 kg ha-1 yr-1. Dry deposition declined during the summer months, due to lower pollutant concentrations and temperature-induced closure of the plant stomata during afternoon hours.
Plant aboveground biomass data: Long-Term Nitrogen Deposition During Grassland Succession
The purpose of this experiment is to measure how initially disturbing an area and adding nitrogen over a long time will affect the number of species, the type of species present, the amount of annual growth, and the change from year to year in the growth of each species in a plant community which is also relieved of grazing by large and small mammals. This experiment is conducted within fields (A, B, and C) which were initially low in soil nutrients. The ground was disturbed by thoroughly disking the area prior to establishment of the experiment. There are 8 different levels of nitrogen addition with other nutrients added to ensure that nitrogen remains the limiting nutrient, and a control which receives no nutrients. Nitrogen fertilizer (NH4NO3) is applied twice per year, once in early May and once in late June. There are six replicates of each treatment per field. The treatments were randomly assigned to plots of size 4 by 4 meters. The plots are in 6 plot by 9 plot grids with 1 meter aisles between plots. The plot grids are enclosed by a fence to keep out mammalian herbivores. Gophers are trapped and removed as they appear. In the spring of 1992, subexperiments E097 and E098 were established. E097 is in fields A and C where randomly selected plots within each treatment no longer receive fertilizer. E098 is in field B where randomly selected plots within each treatment are burned. Note that the design of E002 is similar to E001 except E002 was thoroughly disked prior to establishment.
Plant aboveground biomass data: Long-Term Nitrogen Deposition: Population, Community, and Ecosystem Consequences
The purpose of this experiment is to measure how adding nitrogen over a long time will affect the number of species, the type of species present, the amount of annual growth, and the change from year to year in the growth of each species in a plant community which is also relieved of grazing by large and small mammals. The experiment is being conducted within fields (A, B, C, and D) which were initially low in soil nutrients. There are 8 different levels of nitrogen addition with other nutrients added to ensure that nitrogen remains the limiting nutrient, and a control which receives no nutrients. There are 6 replicates of the 9 treatments in fields A, B, and C and 5 replicates in field D. The treatments were randomly assigned to the plots. In fields A, B, and C the plots are in 6 by 9 grids and are 4 by 4 meters in size with 1 meter aisles between plots. In field D the plots are 1.5 by 4 meters and are placed in a 3 by 17 grid. The plots are enclosed by a fence to keep out mammalian herbivores. Gophers are trapped and removed as they appear. Nitrogenfertilizer (NH4NO3) is applied twice per year, once in early May and once in late June. This experiment was begun in 1982 by David Tilman.
Root biomass data: Long-Term Nitrogen Deposition: Population, Community, and Ecosystem Consequences
The purpose of this experiment is to measure how adding nitrogen over a long time will affect the number of species, the type of species present, the amount of annual growth, and the change from year to year in the growth of each species in a plant community which is also relieved of grazing by large and small mammals. The experiment is being conducted within fields (A, B, C, and D) which were initially low in soil nutrients. There are 8 different levels of nitrogen addition with other nutrients added to ensure that nitrogen remains the limiting nutrient, and a control which receives no nutrients. There are 6 replicates of the 9 treatments in fields A, B, and C and 5 replicates in field D. The treatments were randomly assigned to the plots. In fields A, B, and C the plots are in 6 by 9 grids and are 4 by 4 meters in size with 1 meter aisles between plots. In field D the plots are 1.5 by 4 meters and are placed in a 3 by 17 grid. The plots are enclosed by a fence to keep out mammalian herbivores. Gophers are trapped and removed as they appear. Nitrogenfertilizer (NH4NO3) is applied twice per year, once in early May and once in late June. This experiment was begun in 1982 by David Tilman.
Soil nitrogen: Long-Term Nitrogen Deposition During Grassland Succession
The purpose of this experiment is to measure how initially disturbing an area and adding nitrogen over a long time will affect the number of species, the type of species present, the amount of annual growth, and the change from year to year in the growth of each species in a plant community which is also relieved of grazing by large and small mammals. This experiment is conducted within fields (A, B, and C) which were initially low in soil nutrients. The ground was disturbed by thoroughly disking the area prior to establishment of the experiment. There are 8 different levels of nitrogen addition with other nutrients added to ensure that nitrogen remains the limiting nutrient, and a control which receives no nutrients. Nitrogen fertilizer (NH4NO3) is applied twice per year, once in early May and once in late June. There are six replicates of each treatment per field. The treatments were randomly assigned to plots of size 4 by 4 meters. The plots are in 6 plot by 9 plot grids with 1 meter aisles between plots. The plot grids are enclosed by a fence to keep out mammalian herbivores. Gophers are trapped and removed as they appear. In the spring of 1992, subexperiments E097 and E098 were established. E097 is in fields A and C where randomly selected plots within each treatment no longer receive fertilizer. E098 is in field B where randomly selected plots within each treatment are burned. Note that the design of E002 is similar to E001 except E002 was thoroughly disked prior to establishment.
Soil carbon: Long-Term Nitrogen Deposition During Grassland Succession
The purpose of this experiment is to measure how initially disturbing an area and adding nitrogen over a long time will affect the number of species, the type of species present, the amount of annual growth, and the change from year to year in the growth of each species in a plant community which is also relieved of grazing by large and small mammals. This experiment is conducted within fields (A, B, and C) which were initially low in soil nutrients. The ground was disturbed by thoroughly disking the area prior to establishment of the experiment. There are 8 different levels of nitrogen addition with other nutrients added to ensure that nitrogen remains the limiting nutrient, and a control which receives no nutrients. Nitrogen fertilizer (NH4NO3) is applied twice per year, once in early May and once in late June. There are six replicates of each treatment per field. The treatments were randomly assigned to plots of size 4 by 4 meters. The plots are in 6 plot by 9 plot grids with 1 meter aisles between plots. The plot grids are enclosed by a fence to keep out mammalian herbivores. Gophers are trapped and removed as they appear. In the spring of 1992, subexperiments E097 and E098 were established. E097 is in fields A and C where randomly selected plots within each treatment no longer receive fertilizer. E098 is in field B where randomly selected plots within each treatment are burned. Note that the design of E002 is similar to E001 except E002 was thoroughly disked prior to establishment.
Counts of White-Tailed Deer Florivory: Long-Term Nitrogen Deposition: Population, Community, and Ecosystem Consequence
These data were collected in the e001 experiment within Field C to better characterize the impact of white-tailed deer on the plant community. These data represent counts of plant stems with an inflorescence present or those with evidence of herbivory that was interpreted as deer florivory.
Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Soil Temperature Data from the Sevilleta National Wildlife Refuge, New Mexico (1/2006 - 7/2009)
This data set provides soil temperature data in each plot of the warming experiment (see SEV176). Data are collected with automated soil temperature probes at 15-minute intervals at two soil depths under grass and bare patches in each of the 40 plots.
Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Soil Moisture Data from the Sevilleta National Wildlife Refuge, New Mexico (1/2006-8/2009)
This data set provides soil moisture data in each plot of the warming experiment (see SEV176). Data are collected with automated soil moisture probes at 30-minute intervals at two soil depths under grass and bare patches in each of the 40 plots.
Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Soil Temperature, Moisture, and Carbon Dioxide Data from the Sevilleta National Wildlife Refuge, New Mexico
Humans are creating significant global environmental change, including shifts in climate, increased nitrogen (N) deposition, and the facilitation of species invasions. A multi-factorial field experiment is being performed in an arid grassland within the Sevilleta National Wildlife Refuge (NWR) to simulate increased nighttime temperature, higher N deposition, and heightened El Nino frequency (which increases winter precipitation by an average of 50%). The purpose of the experiment is to better understand the potential effects of environmental drivers on grassland community composition, aboveground net primary production and soil respiration. The focus is on the response of two dominant grasses (Bouteloua gracilis and B eriopoda), in an ecotone near their range margins and thus these species may be particularly susceptible to global environmental change. It is hypothesized that warmer summer temperatures and increased evaporation will favor growth of black grama (Bouteloua eriopoda), a desert grass, but that increased winter precipitation and/or available nitrogen will favor the growth of blue grama (Bouteloua gracilis), a shortgrass prairie species. Treatment effects on limiting resources (soil moisture, nitrogen availability, species abundance, and net primary production (NPP) are all being measured to determine the interactive effects of key global change drivers on arid grassland plant community dynamics and ecosystem processes. This dataset shows values of soil moisture, soil temperature, and the CO2 flux of the amount of CO2 that has moved from soil to air. On 4 August 2009 lightning ignited a ~3300 ha wildfire that burned through the experiment and its surroundings. Because desert grassland fires are patchy, not all of the replicate plots burned in the wildfire. Therefore, seven days after the wildfire was extinguished, the Sevilleta NWR Fire Crew thoroughly burned the remaining plots allowing us to assess experimentally the effects of interactions among multip
Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Soil Nitrogen Data from the Sevilleta National Wildlife Refuge, New Mexico (2006 - 2020)
Humans are creating significant global environmental change, including shifts in climate, increased nitrogen (N) deposition, and the facilitation of species invasions. A multi-factorial field experiment is being performed in an arid grassland within the Sevilleta National Wildlife Refuge (NWR) to simulate increased nighttime temperature, higher N deposition, and heightened El Niño frequency (which increases winter precipitation by an average of 50%). The purpose of the experiment is to better understand the potential effects of environmental drivers on grassland community composition, aboveground net primary production and soil respiration. The focus is on the response of two dominant grasses (Bouteloua gracilis and B eriopoda), in an ecotone near their range margins and thus these species may be particularly susceptible to global environmental change. It is hypothesized that warmer summer temperatures and increased evaporation will favor growth of black grama (Bouteloua eriopoda), a desert grass, but that increased winter precipitation and/or available nitrogen will favor the growth of blue grama (Bouteloua gracilis), a shortgrass prairie species. Treatment effects on limiting resources (soil moisture, nitrogen availability, species abundance, and net primary production (NPP) are all being measured to determine the interactive effects of key global change drivers on arid grassland plant community dynamics and ecosystem processes. On 4 August 2009 lightning ignited a ~3300 ha wildfire that burned through the experiment and its surroundings. Because desert grassland fires are patchy, not all of the replicate plots burned in the wildfire. Therefore, seven days after the wildfire was extinguished, the Sevilleta NWR Fire Crew thoroughly burned the remaining plots allowing us to assess experimentally the effects of interactions among multiple global change presses and a pulse disturbance on post-fire grassland dynamics. This data set provides soil N availability in each
Fungal responses to plant invasion are greater under soil warming than simulated nitrogen deposition data
<p>This file includes the data associated with analyzing scripts for the following github entry: <a href="https://gitlab.ethz.ch/manthony/swan-x-invasion">https://gitlab.ethz.ch/manthony/swan-x-invasion</a>. </p> <p>This project studied the combined effects of nitrogen deposition, soil warming, and Alliaria petiolata (garlic mustard) invasion on soil fungal communities, functional genes, and soil physical and chemical properties.</p>
Data from: Ectomycorrhizal fungi are more sensitive to high soil nitrogen levels in forests exposed to nitrogen deposition
<p>Ectomycorrhizal fungi are essential for nitrogen cycling in many temperate forests and responsive to anthropogenic nitrogen addition, which generally, decreases host carbon allocation to the fungi. In the boreal region, however, ectomycorrhizal fungal biomass has been found to correlate positively with soil nitrogen availability. Still, responses to anthropogenic input, for instance through atmospheric deposition, are commonly negative.</p> <p>To elucidate whether variation in nitrogen supply affects ectomycorrhizal fungi differently depending on geographical context, we investigated ectomycorrhizal fungal communities along two fertility gradients across nemo-boreal forests with similar ranges in soil N/C ratios and inorganic nitrogen availability but located in regions with contrasting rates of nitrogen deposition.</p> <p>Ectomycorrhizal biomass and community composition remained relatively stable across the nitrogen-gradient with low atmospheric nitrogen deposition, but biomass decreased, and the community changed more drastically, with increasing nitrogen availability in the gradient subjected to higher rates of nitrogen deposition. Moreover, potential activities of enzymes involved in ectomycorrhizal mobilisation of organic nitrogen decreased as N/C ratios increased.</p> <p>In forests with low external input, we propose that stabilising feedbacks in tree-fungal interactions maintain ectomycorrhizal fungal biomass and communities even in highly fertile soils. In contrast, anthropogenic nitrogen input seems to impair ectomycorrhizal functions.</p>
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