EPA Science Inventory

Search Criteria: the term 'nitrogen OR phosphorus OR nutrient' in any part of any record.
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    Integrated Science Assessment (ISA) for Oxides of Nitrogen – Health Criteria (First External Review Draft, 2013) (ASSESSMENT DOCUMENT)
    EPA is announcing the availability of the First External Review Draft of the <i>Integrated Science Assessment for Oxides of Nitrogen – Health Criteria</I> for public comment and independent peer review. This draft document provides EPA’s evaluation and synthesis of the most polic...
    Integrated Science Assessment (ISA) for Oxides of Nitrogen, Oxides of Sulfur and Particulate Matter - Ecological Criteria (First External Review Draft, Mar 2017) (ASSESSMENT DOCUMENT)
    This draft ISA document represents a concise synthesis and evaluation of the most policy-relevant science and will ultimately provide the scientific bases for EPA’s decision on retaining or revising the current secondary standards for NO2, SO2, PM 2.5 and PM 10 since the prior re...
    A modeling study examining the impact of nutrient boundaries on primary production on the Louisiana Continental Shelf (JOURNAL)
    A mass balance eutrophication model, Gulf of Mexico Dissolved Oxygen Model (GoMDOM), has been developed and applied to describe nitrogen, phosphorus and primary production in the Louisiana shelf of the Gulf of Mexico. Features of this model include bi-directional boundary exchan...
    Latitudinal gradients in oceanic and watershed nitrogen sources to Pacific coast estuaries of North America (PRESENTATION)
    To assess the relative importance of terrestrial versus oceanic nutrient sources, we assembled natural abundance nitrogen stable isotope (&delta;15N) data for nitrate, green macroalgae, seagrass (Zostera marina) and mussels in the nearshore and in estuaries along the west coast o...
    Unexpected Responses of autotrophs to nutrient loading: Influence of water residence time on eutrophication expression (PRESENTATION)
    Water residence time may critically influence the expression of estuarine eutrophication symptoms such as phytoplankton blooms, anoxia/hypoxia, build-up of organic matter, and altered community composition. While a conceptual model was developed in the late 1990&rsquo;s; pioneer...
    Comparative analysis of long-term chlorophyll data with generalized additive model - San Francisco Bay and St. Lucie Estuary (PRESENTATION)
    The health of estuarine ecosystems is often influenced by hydraulic and nutrient loading from upstream watersheds. We examined four decades of monitoring data of nutrient export into the Indian River Lagoon and San Francisco Bay, both of which have received considerable attentio...
    Linking terrestrial phosphorus inputs to riverine export across the United States (JOURNAL)
    Humans have greatly accelerated phosphorus (P) flows from land to aquatic ecosystems, causing eutrophication, harmful algal blooms, and hypoxia. A variety of statistical and mechanistic models have been used to explore the relationship between P management on land and P losses to...
    Modeling Historical and Projected Future Atmospheric Nitrogen Loading to the Chesapeake Bay Watershed (PRESENTATION)
    Land use and climate change are expected to alter key processes in the Chesapeake Bay watershed and can potentially exacerbate the impact of excess nitrogen. Atmospheric sources are one of the largest loadings of nitrogen to the Chesapeake Bay watershed. In this study, we explore...
    Modeling the Air-Vegetation-Soil Exchange of Reactive Nitrogen (PRESENTATION)
    Nitrogen is an essential building block of all proteins and thus an essential nutrient for all life. However, in excess reactive nitrogen can lead to poor air or water quality, loss of biodiversity, and impact respiratory and cardiac health. Human activity has perturbed this cycl...
    Projections of Atmospheric Nutrient Deposition to the Chesapeake Bay Watershed (PRESENTATION)
    Atmospheric deposition remains one of the largest loadings of nutrients to the Chesapeake Bay watershed. The interplay between future land use, climate, and emission changes, however, will cause shifts in the future nutrient deposition regime (e.g., oxidized vs. reduced nitrogen...
    New, national bottom-up estimate for tree-based biological nitrogen fixation in the US (PRESENTATION)
    Nitrogen is a limiting nutrient in many ecosystems, but is also a chief pollutant from human activity. Quantifying human impacts on the nitrogen cycle and investigating natural ecosystem nitrogen cycling both require an understanding of the magnitude of nitrogen inputs from biolo...
    Nitrogen input inventory in the Nooksack-Abbotsford-Sumas Transboundary Region: Key component of an international nitrogen management study. (PRESENTATION)
    Background/Question/Methods: Nitrogen (N) is an essential biological element, so optimizing N use for food production while minimizing the release of N and co-pollutants to the environment is an important challenge. The Nooksack-lower Fraser Valley, spanning a portion of the w...
    Development of an epiphyte indicator of nutrient enrichment. A critical evaluation of observational and experimental studies (JOURNAL)
    An extensive review of the literature on epiphytes on submerged aquatic vegetation (SAV), primarily seagrasses but including some brackish and freshwater rooted macrophytes, was conducted in order to evaluate the evidence for response of epiphyte metrics to increased nutrients. ...
    Nitrogen input inventory in the Nooksack-Abbotsford-Sumas Transboundary Region: Key component of an international nitrogen management study (PRESENTATION)
    Nitrogen (N) is an essential biological element, so optimizing N use for food production while minimizing the release of N and co-pollutants to the environment is an important challenge. The Nooksack-Abbotsford-Sumas Transboundary (NAS) Region, spanning a portion of the western...
    Trends in nitrogen isotope ratios of juvenile winter flounder reflect changing nitrogen inputs to Rhode Island, USA estuarine systems (JOURNAL)
    Nitrogen isotope ratios (d 15N) in juvenile winter flounder, Pseudopleuronectes americanus, were used to examine changes in nitrogen inputs to several Rhode Island, USA estuarine systems. Fish were collected over two three-year periods with a ten-year interval between sampling pe...
    Using Stable Isotopes to Assess Connectivity: the Importance of Oceanic and Watershed Nitrogen Sources for Estuarine Primary Producers (PRESENTATION)
    Estuaries located at the interface of terrestrial and oceanic ecosystems receive nutrients from both ecosystems. Stable isotopes of primary producers and consumers are often used as an indicator of nutrient sources. We assembled natural abundance nitrogen stable isotope (δ15N) d...
    Modeling and Recent Shift in the Composition of Atmospheric Reactive Nitrogen (PRESENTATION)
    Nitrogen is an essential building block of all proteins and thus an essential nutrient for all life. Reactive nitrogen, which is naturally produced via enzymatic reactions, forest fires and lightning, is continually recycled and cascades through air, water, and soil media. Human ...
    Chronic nitrogen deposition influences the chemical dynamics of leaf litter and fine roots during decomposition (JOURNAL)
    Atmospheric nitrogen deposition induces a forest carbon sink across broad parts of the Northern Hemisphere; this carbon sink may partly result from slower litter decomposition. Although microbial responses to experimental nitrogen deposition have been well-studied, evidence linki...
    The nitrogen footprint tool network: a multi-institution program to reduce nitrogen pollution (JOURNAL)
    Anthropogenic sources of reactive nitrogen have local and global impacts on air and water quality and detrimental effects on human and ecosystem health. This paper uses the nitrogen footprint tool (NFT) to determine the amount of nitrogen (N) released as a result of institutional...
    Comparing Institution Nitrogen Footprints: Metrics for Assessing and Tracking Environmental Impact (JOURNAL)
    When multiple institutions with strong sustainability initiatives use a new environmental impact assessment tool, there is an impulse to compare. The first seven institutions to calculate their nitrogen footprints using the nitrogen footprint tool have worked collaboratively to i...
    Growth, morphometrics and nutrient content of farmed eastern oysters, Crassostrea virginica (Gmelin), in New Hampshire, USA (JOURNAL)
    When harvested, oysters represent a removal from the ecosystem of nutrients such as nitrogen (N)and carbon (C). A number of factors potentially affect nutrient content, but a quantitative understanding across the geographical range of the eastern oysters is lacking. This study wa...
    A Case Study on Nitrogen Uptake and Denitrification in a Restored Urban Stream in Baltimore, Maryland (PRESENTATION)
    Restoring urban infrastructure and managing the nitrogen cycle represent emerging challenges for urban water quality. We investigated whether stormwater control measures (SCMs), a form of green infrastructure, integrated into restored and degraded urban stream networks can influe...
    Research to Inform Nutrient Thresholds and Prioritization of Watersheds for Nutrient Management (PRESENTATION)
    The information in this presentation focuses on SSWR's 4.02 project, which will advance the science needed to inform decisions to prioritize watersheds and nutrient sources for nutrient management and define appropriate nutrient levels for the nation&rsquo;s waters, two importan...
    Watershed modeling and monitoring for assessing nutrient trading viability and increasing the adoption of nutrient management practices (PRESENTATION)
    Presentation for the American Water Works Association Water Sustainability Conference. The presentation highlights latest results from water quality trading research conducted by ORD using the East Fork Watershed in Southwestern Ohio as a case study. The watershed has a nutrient ...
    Long-Term Simulated Atmospheric Nitrogen Deposition Alters Leaf and Fine Root Decomposition (JOURNAL)
    Atmospheric nitrogen deposition has been suggested to increase forest carbon sequestration across much of the Northern Hemisphere; slower organic matter decomposition could contribute to this increase. At four sugar maple (Acer saccharum)-dominated northern hardwood forests, we p...