Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"nitrogen deposition"”.
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Nitrogen deposition and nitrification in coniferous forests’
The increased inorganic nitrogen (N) deposition in the last decades has become a major concern for the health of forest ecosystems. High anthropogenic N emissions, mainly from fossil fuel combustion and livestock agriculture, have resulted in both high gaseous concentrations and high deposition in …
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Metabolic differentiation in the lichen Cladonia portentosa from different wet nitrogen deposition regimes’
The deposition of atmospheric nitrogen is now recognized as a major driver of<br/>biodiversity changes at mid to high latitudes. It has previously been shown that<br/>regional variations in wet nitrogen deposition in the British Isles are reflected in<br/>broad targeted chemical parameters in the …
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EFFECTS OF NITROGEN DEPOSITION ON BOREAL BOGS: A THREE YEAR NITROGEN FERTILIZATION AND TRACER EXPERIMENT
… cycling. Oligotrophic bogs are naturally nitrogen (N) limited, receiving nutrients only via atmospheric deposition. Increased nutrient deposition, particularly N will almost certainly change the microbiology, biogeochemistry, and C and nutrient balances in bogs. Both primary production and …
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The effect of simulated nitrogen deposition on growth and ecosystem functioning of managed P. patula plantation ecosystems in South Africa
… to investigate the effects of future NO₃ and NH₄ deposition on growth and nutrient cycling in P. patula plantations growing on shale-derived soil. This study consists of a field and pot-grown seedling experiments, the former commencing in November 1995 and the latter in August 1996.
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Modeling of N2O emission from unmanaged terrestrial ecosystem soils
… and moist tropical forest and areas with high nitrogen deposition are the major sources of N2O emissions, while there are significantly low emissions from the high latitude ecosystems as a result of low temperature and high soil nitrogen limitation. These results are consistent with both …
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The effects of temperature and moisture on alpine microbial processes across a gradient of soil development
… by global change. Climate change and atmospheric nitrogen deposition are exposing soils to novel temperature regimes, melting alpine glaciers, altering precipitation patterns, and directly introducing bioavailable nutrients. Because microbial communities are important drivers of nutrient cycling …
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Global change drivers and their impact on herbaceous, ant, and grasshopper assemblages in an African semi-arid savanna
… As savannas are nutrient limited, an increase in nitrogen deposition will have major consequences for vegetation structure and this can only be exacerbated by increased rainfall amounts. Current research suggests that these predicted increases in water and nutrients will result in increasing grass …
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Potential of temporal and spatial analysis techniques as tools for exploring changes in forest site productivity and following environmental interactions : Finnish-German comparative study
… change, increasing CO2, foliar nutrition, nitrogen deposition, were assessed for the complete data set of 33 sites in Finland and 32 sites in Germany. <br>The most important investigated anthropogenic influences on site productivity changes were the deposition of nitrogen (oxidized and …
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Carbon storage in grasslands : the impact of atmospheric nitrogen pollution
Atmospheric nitrogen deposition is a major threat to biodiversity and ecosystem service provision around the globe. It is known that nitrogen enrichment affects various chemical and biological processes involved in carbon cycling and storage in soil. This is especially significant as soil carbon …
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Identifying long term patterns and drivers of vegetation structure in an African savanna using stable carbon and nitrogen isotopes
… This study aims to investigate vegetation and Nitrogen cycling changes over time in a diverse patch mosaic landscape in Hluhluwe-iMfolozi Park to identify drivers of vegetation structure and their dynamism over time. Sediment from a 150cm core (taken using a Russian corer) was analyzed for …
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Seasonal, biogeochemical, and microbial response of soils to simultaneous warming and nitrogen additions
<p>Climate warming and nitrogen deposition are global environmental threats that could alter soil microbial communities and the biogeochemical processes they perform. Few studies have examined interactive effects of elevated temperatures and nitrogen inputs. Many studies have also not considered …
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Exploring interactions between agriculture and air quality on regional to global scales
… restrictions. We also assess the effect of nitrogen deposition on crops compared to PM. Overall, we highlight the need for better observations of both ammonia concentrations and the impacts of PM on crop growth to reduce uncertainty in these interactions.
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Effects of Acid Deposition and Changing Climate on the Hydrochemistry and Critical Loads of Watersheds in the Adirondack Region of New York
<p>Despite decreases in acidic deposition since the 1970s, the recovery of surface waters from acidification has been limited primarily due to the depletion of exchangeable base cations, net mineralization of organic sulfur and nitrogen and release of previously retained SO42- and NO3-, and …
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Understanding drivers of long-term change in semi-natural habitats.
… in species composition across the survey period. Nitrogen deposition may have contributed towards community changes between 1970 and 1990, as indicated by the change in soil properties and the associated decline in species diversity. However, between 1990 and 2016 vegetation change is likely to be …
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Impact of spatial and temporal distribution of ammonia emissions from chemical fertilizer usage on predictions of air quality in the Midwest United States
… protect human health and visibility. Atmospheric deposition of NH3 and other reactive nitrogen compounds exacerbates surface water eutrophication, soil acidity and ecosystem damages. Accurate prediction of impacts of NH3 emissions on PM formation and reactive nitrogen deposition using chemical …
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