31 research outputs found
Trends in stream nitrogen concentrations for forested reference catchments across the USA
To examine whether stream nitrogen concentrations in forested reference catchments have changed over time and if patterns were consistent across the USA, we synthesized up to 44 yr of data collected from 22 catchments at seven USDA Forest Service Experimental Forests. Trends in stream nitrogen presented high spatial variability both among catchments at a site and among sites across the USA. We found both increasing and decreasing trends in monthly flow-weighted stream nitrate and ammonium concentrations. At a subset of the catchments, we found that the length and period of analysis influenced whether trends were positive, negative or non-significant. Trends also differed among neighboring catchments within several Experimental Forests, suggesting the importance of catchment-specific factors in determining nutrient exports. Over the longest time periods, trends were more consistent among catchments within sites, although there are fewer long-term records for analysis. These findings highlight the critical value of long-term, uninterrupted stream chemistry monitoring at a network of sites across the USA to elucidate patterns of change in nutrient concentrations at minimally disturbed forested sites
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Trends in stream nitrogen concentrations for forested reference catchments across the USA
To examine whether stream nitrogen concentrations in forested reference catchments have
changed over time and if patterns were consistent across the USA, we synthesized up to 44 yr
of data collected from 22 catchments at seven USDA Forest Service Experimental Forests.
Trends in stream nitrogen presented high spatial variability both among catchments at a site
and among sites across the USA. We found both increasing and decreasing trends in monthly
flow-weighted stream nitrate and ammonium concentrations. At a subset of the catchments,
we found that the length and period of analysis influenced whether trends were positive,
negative or non-significant. Trends also differed among neighboring catchments within several
Experimental Forests, suggesting the importance of catchment-specific factors in determining
nutrient exports. Over the longest time periods, trends were more consistent among
catchments within sites, although there are fewer long-term records for analysis. These
findings highlight the critical value of long-term, uninterrupted stream chemistry monitoring
at a network of sites across the USA to elucidate patterns of change in nutrient concentrations
at minimally disturbed forested sites.Keywords: forested catchment, nitrate, trends, stream, reference catchments, ammoniumKeywords: forested catchment, nitrate, trends, stream, reference catchments, ammoniu
Carbon balance for different management practices for fast growing tree species planted on former pastureland in southern Europe: a case study using the CO2Fix model
IL-6 production in the vascular adventitia and adventitia-media-crosstalk in neointima formation
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ArgerichAlbaFESTrendsStreamNitrogen.pdf
To examine whether stream nitrogen concentrations in forested reference catchments have
changed over time and if patterns were consistent across the USA, we synthesized up to 44 yr
of data collected from 22 catchments at seven USDA Forest Service Experimental Forests.
Trends in stream nitrogen presented high spatial variability both among catchments at a site
and among sites across the USA. We found both increasing and decreasing trends in monthly
flow-weighted stream nitrate and ammonium concentrations. At a subset of the catchments,
we found that the length and period of analysis influenced whether trends were positive,
negative or non-significant. Trends also differed among neighboring catchments within several
Experimental Forests, suggesting the importance of catchment-specific factors in determining
nutrient exports. Over the longest time periods, trends were more consistent among
catchments within sites, although there are fewer long-term records for analysis. These
findings highlight the critical value of long-term, uninterrupted stream chemistry monitoring
at a network of sites across the USA to elucidate patterns of change in nutrient concentrations
at minimally disturbed forested sites
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ArgerichAlbaFESTrendsStreamNitrogen(Supplementary Material).pdf
To examine whether stream nitrogen concentrations in forested reference catchments have
changed over time and if patterns were consistent across the USA, we synthesized up to 44 yr
of data collected from 22 catchments at seven USDA Forest Service Experimental Forests.
Trends in stream nitrogen presented high spatial variability both among catchments at a site
and among sites across the USA. We found both increasing and decreasing trends in monthly
flow-weighted stream nitrate and ammonium concentrations. At a subset of the catchments,
we found that the length and period of analysis influenced whether trends were positive,
negative or non-significant. Trends also differed among neighboring catchments within several
Experimental Forests, suggesting the importance of catchment-specific factors in determining
nutrient exports. Over the longest time periods, trends were more consistent among
catchments within sites, although there are fewer long-term records for analysis. These
findings highlight the critical value of long-term, uninterrupted stream chemistry monitoring
at a network of sites across the USA to elucidate patterns of change in nutrient concentrations
at minimally disturbed forested sites
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ArgerichAlbaFESTTrendsStreamNitrogen(VideoAbstract).mp4
To examine whether stream nitrogen concentrations in forested reference catchments have
changed over time and if patterns were consistent across the USA, we synthesized up to 44 yr
of data collected from 22 catchments at seven USDA Forest Service Experimental Forests.
Trends in stream nitrogen presented high spatial variability both among catchments at a site
and among sites across the USA. We found both increasing and decreasing trends in monthly
flow-weighted stream nitrate and ammonium concentrations. At a subset of the catchments,
we found that the length and period of analysis influenced whether trends were positive,
negative or non-significant. Trends also differed among neighboring catchments within several
Experimental Forests, suggesting the importance of catchment-specific factors in determining
nutrient exports. Over the longest time periods, trends were more consistent among
catchments within sites, although there are fewer long-term records for analysis. These
findings highlight the critical value of long-term, uninterrupted stream chemistry monitoring
at a network of sites across the USA to elucidate patterns of change in nutrient concentrations
at minimally disturbed forested sites
Soil carbon availability decouples net nitrogen mineralization and net nitrification across United States Long Term Ecological Research sites
Autotrophic and heterotrophic organisms require resources in stoichiometrically balanced ratios of carbon (C) to nutrients, the demand for which links organismal and ecosystem-level biogeochemical cycles. In soils, the relative availability of C and nitrogen (N) also defines the strength of competition for ammonium between autotrophic nitrifiers and heterotrophic decomposers, which may influence the coupled dynamics between N mineralization and nitrification. Here, we use data from the publicly available US National Science Foundation funded Long Term Ecological Research (LTER) network to evaluate the influence of soil C concentration on the relationship between net nitrification and net N mineralization. We found that soil C availability constrains the fraction of mineralized N that is ultimately nitrified across the continental gradient, contributing to reduced rates of nitrification in soils with high C concentrations. Nitrate, which is produced by nitrification, is a highly mobile ion that easily leaches to aquatic ecosystems or denitrifies into the greenhouse gas nitrous oxide (N2O). Understanding the connection between soil C concentration and soil N transformations is thus important for managing potential ecosystem N losses, understanding the biogeochemical constraints of these losses, and accurately representing coupled C-N dynamics in ecosystem models
Mitochondrial Complex IV Subunit 4 Isoform 2 Is Essential for Acute Pulmonary Oxygen Sensing
Wildland Fire in Ecosystems Effects of Fire on Soil and Water
This state-of-knowledge review about the effects of fire on soils and water can assist land and fire managers with information on the physical, chemical, and biological effects of fire needed to successfully conduct ecosystem management, and effectively inform others about the role and impacts of wildland fire. Chapter topics include the soil resource, soil physical properties and fire, soil chemistry effects, soil biology responses, the hydrologic cycle and water resources, water quality, aquatic biology, fire effects on wetland and riparian systems, fire effects models, and watershed rehabilitation