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Nuisance blooms of heterocystous Cyanobacteria in Lake Winnipeg have nearly doubled in size since the mid 1990s. The increases are the result of a recent rapid increase in loading and concentration of phosphorus. The rapid increase in phosphorus is largely the result of two factors. The first factor is the result of rapidly increased livestock production and use of synthetic fertilizer in the Red River Valley, with smaller contributions of phosphorus from the city of Winnipeg and other human development in the Red and Winnipeg river basins. The second factor is the increased frequency and intensity of spring floods in the Red River watershed in recent years, which have greatly enhanced the transfer of phosphorus...
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Mangrove restoration has a strong potential to enhance the services provided by coastal wetlands on a number of Department of the Interior (DOI) managed lands throughout the southeastern United States of America. Services include storm protection, water quality improvement, and biological carbon sequestration. Forest structural attributes including basal area, tree height, and stem density by species are used to calculate above ground biomass and above ground productivity. Percent cover is used to asses the forest canopy health. The data collected for the soils are: bulk density, percent total Nitrogen, percent total Carbon, and selected samples percent total Phosporus. The forest structure plots were placed in...
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the nine Chesapeake Bay River Input Monitoring (RIM) stations for the period 1985 through 2015. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). Yields (represents the mass of constituent transported from a unit area of a given watershed) are used to compare the export loads from one basin to another. Yield results are obtained by dividing the annual load (pounds) of a given constituent by the respective watershed...
Phosphorus and nitrogen uptake capacities were assessed during 36–58 d drying cycles to determine whether the ability of sagebrush (Artemisia tridentata Nutt.) to absorb these nutrients changed as the roots were subjected to increasing levels of water stress. Water was withheld from mature plants in large (6 I) containers and the uptake capacity of excised roots in solution was determined as soil water potentials decreased from −0.03 MPa to −5.0 MPa. Phosphorus uptake rates of excised roots at given substrate concentrations increased as preharvest soil water potentials decreased to −5.0 MPa. Vmax and Km also increased as soil water potentials declined. Declining soil water potentials depressed nitrogen uptake...
Phosphorus (P) has been proposed to directly limit primary productivity in some temperate grassland ecosystems. Our study of a recovering prairie on Colorado's Front Range suggests that P availability, possibly via regulation of nitrogen (N) fixation, may strongly influence N availability in recovering prairie soils. Consequently, increased P availability could indirectly affect plant growth through the alleviation of N limitation. At our site, concentrations of soil inorganic N were nearly three times higher in plots fertilized with P than in control plots. Subsequent acetylene reduction analyses showed that soil N fixation rates were more than double for P fertilization plots. These results highlight potential...
Interspecific variation in polyphenol production by plants has been interpreted in terms of defense against herbivores. Several recent lines of evidence suggest that polyphenols also influence the pools and fluxes of inorganic and organic soil nutrients. Such effects could have far-ranging consequences for nutrient competition among and between plants and microbes, and for ecosystem nutrient cycling and retention. The significance of polyphenols for nutrient cycling and plant productivity is still uncertain, but it could provide an alternative or complementary explanation for the variability in polyphenol production by plants. Published in Trends in Ecology & Evolution, volume 15, issue 6, on pages 238 - 243, in...
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay Nontidal Network (NTN) stations for the period 1985 through 2016. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment that was exported from each of the NTN watersheds. To determine the trend in loads, the annual load results are flow normalized to integrate out the year-to-year variability in river discharge....
N limitation to primary production and other ecosystem processes is widespread. To understand the causes and distribution of N limitation, we must understand the controls of biological N fixation. The physiology of this process is reasonably well characterized, but our understanding of ecological controls is sparse, except in a few cultivated ecosystems. We review information on the ecological controls of N fixation in free-living cyanobacteria, vascular plant symbioses, and heterotrophic bacteria, with a view toward developing improved conceptual and simulation models of ecological controls of biological N fixation. A model (Howarth et al. 1999) of cyanobacterial fixation in lakes (where N fixation generally increases...
The availability of nutrients is a critical determinant of ecological dynamics in grasslands, but the relationships between soil resource availability and nutrient limitation across ecosystems are not clear. To better understand how soil nutrient availability determines nutrient limitation in vegetation, we grew the same species of grass (Schizachyrium scoparium) in 98 North American grassland soils and fertilized them factorially with nitrogen (N) and phosphorus (P). On average adding N, P, and the two nutrients together increased biomass relative to unfertilized plants by 81%, 22%, and 131%, respectively. Plants grown on low-P soils were not primarily limited by P. Instead, these plants were colimited by N and...
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This data shows select streamgage locations throughout the Red River of the North Basin upstream of Emerson, Manitoba, and basin outlines for eight subbasins..
Geostatistical analyses show that the distribution of soil N, P and K is strongly associated with the presence of shrubs in desert habitats. Shrubs concentrate the biogeochemical cycle of these elements in ?islands of fertility? that are localized beneath their canopies, while adjacent barren, intershrub spaces are comparatively devoid of biotic activity. Both physical and biological processes are involved in the formation of shrub islands. Losses of semiarid grassland in favor of invading shrubs initiate these changes in the distribution of soil nutrients, which may promote the further invasion and persistence of shrubs and cause potential feedbacks between desertification and the Earth's climate system. Published...
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Effects of annual additions of mineral N and P (100 kg ha-1) on plant species composition and annual aboveground net primary production (ANPP) were investigated during the first three years following disturbance in a semi-arid ecosystem. Additions of N reduced richness of perennial plant species during years 2 and 3, while P reduced the number of perennial species only in year 3. From year 1 to year 2, annual and biennial species richness declined in all treatments while ANPP of annual species increased greatly. Added N increased ANPP of annual species while it decreased ANPP of most perennial species relative to the unfertilized control treatment. Community similarities were higher for the control and native vegetation...
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In drylands of southeastern Utah, USA, the invasive exotic grass Bromus tectorum L. occurs in distinct spatial patterns suggesting soil control of ecosystem susceptibility to invasion. To improve our understanding of these patterns, we examined performance of B. tectorum in relation to additions of water, KCl, MgO, and CaO at seventeen 1600 m2 sites distributed across a calcareous soil gradient in Canyonlands National Park. Water additions resulted in a 57% increase in B. tectorum establishment. Fall establishment was significantly correlated with silt and clay content in wet plots but not in dry plots, suggesting that texture effects on B. tectorum establishment patterns may be greater in wet years than in dry...
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay Nontidal Network (NTN) stations for the period 1985 through 2014. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment that was exported from each of the NTN watersheds. To determine the trend in loads, the annual load results are flow normalized to integrate out the year-to-year variability in river discharge....
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay Nontidal Network (NTN) stations for the period 1985 through 2016. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment that was exported from each of the NTN watersheds.
In regions subject to strong winds, considerable amounts of soil are transported off land and deposited to nearby fields and surface water. This study investigated the nutrient supply from deposition of erodible-sized soil to surrounding soil and surface water in a controlled laboratory setting. Wind-erodible fraction (WEF) aggregates were collected from a field with no manure or fertilizer application (Treatment WEF0) and a field that had received 180 Mg ha-1 year-1 of cattle manure (WEF180) for 30 years. The WEF aggregates were applied to a loamy sand soil and to distilled water at rates equivalent to 0, 10, 50, 100, and 150 Mg ha-1 and incubated for 2 years. Deposition of carbon and nutrient-enriched WEF aggregates...
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This USGS Data Release represents tabular data for chemical and physical attributes, rates of deposition, erosion, and mineralization of bank and floodplain sediments and soils from five study sites in the Smith Creek watershed between 2012 and 2015. The data release was produced in compliance with the new 'open data' requirements as a way to make the scientific products associated with USGS research efforts and publications available to the public. The dataset consists of 2 separate items: 1. Smith Creek floodplain soils dataset (tabular data) 2. Smith Creek bank soils dataset (tabular data) These data support the following publication: Gillespie, J.L., Noe, G.B., Hupp, C.R., Gellis, A.C., and Schenk, E.R.,...
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay Nontidal Network (NTN) stations for the period 1985 through 2016. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment that was exported from each of the NTN watersheds.
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These data report the percent of crop acreage, within each basin (basins 1-8, see accompanying shapefiles), enrolled in the Conservation Reserve Program (CRP).
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These data describe the percent of cropland harvested as wheat, corn, and soybean within each basin (basins 1-8, see accompanying shapefiles). Data are available for other crops; however, these three were chosen because wheat is a traditional crop that has been grown for a long time in the Basin and corn and soybeans have increased in recent times because of wetter conditions, the demand for biofuels, and advances in breeding short-season, drought-tolerant crops. The data come from the National Agricultural Statistics Service (NASS) Census of Agriculture (COA) and have estimates for 1974, 1978, 1982, 1986, 1992, 1997, 2002, 2007, and 2012. Years with missing data were estimated estimated using multivariate imputation...
map background search result map search result map Plant community dynamics in a semi-arid ecosystem in relation to nutrient addition following a major disturbance Performance of Bromus tectorum L. in relation to soil properties, water additions, and chemical amendments in calcareous soils of southeastern Utah, USA Conservation Reserve Program Estimates Red River of the North Basin Wheat Corn Soy Estimates Red River of the North Basin Streamgage and basin outline shapefiles for the Red River of the North Floodplain sedimentation, bank erosion, and biogeochemical cycling of sediment and nutrients in Smith Creek (Virginia) 2012-2015: U.S. Geological Survey data release Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay Nontidal Network stations: Water years 1985-2014 Baseline data for a hydrological restoration of a mangrove forest near Goodland, Florida (2015 - 2017) Chesapeake Bay Nontidal Network 2005-2014: Average Yields Chesapeake Bay Nontidal Network 1985-2016: Monthly loads Chesapeake Bay Nontidal Network 1985-2016: Short- and long-term trends Chesapeake Bay Nontidal Network 1985-2016: WRTDS output data Baseline data for a hydrological restoration of a mangrove forest near Goodland, Florida (2015 - 2017) Floodplain sedimentation, bank erosion, and biogeochemical cycling of sediment and nutrients in Smith Creek (Virginia) 2012-2015: U.S. Geological Survey data release Performance of Bromus tectorum L. in relation to soil properties, water additions, and chemical amendments in calcareous soils of southeastern Utah, USA Plant community dynamics in a semi-arid ecosystem in relation to nutrient addition following a major disturbance Conservation Reserve Program Estimates Red River of the North Basin Wheat Corn Soy Estimates Red River of the North Basin Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay Nontidal Network stations: Water years 1985-2014 Chesapeake Bay Nontidal Network 2005-2014: Average Yields Chesapeake Bay Nontidal Network 1985-2016: Monthly loads Chesapeake Bay Nontidal Network 1985-2016: Short- and long-term trends Chesapeake Bay Nontidal Network 1985-2016: WRTDS output data Streamgage and basin outline shapefiles for the Red River of the North