Nitrogen (N) fluxes show a substantial variability at the landscape scale. Emissions are transferred by atmospheric, hydrological and anthropogenic dispersion between different landscape elements or ecosystems, e.g. farms, fields, forests or moorland. These landscape N fluxes can cause impacts to the environment, such as loss of biodiversity. The aim of this study is to illustrate how landscape N fluxes can be quantified by integrating atmospheric and fluvial fluxes in a Scottish landscape of 6 km x 6 km that contains intensively managed poultry farming, extensively managed beef and sheep farming, semi-natural moorland and woodland. Atmospheric ammonia (NH3) emissions of two deep pit free range layer poultry houses were estimated by high time-resolution measurements of NH3 concentrations and meteorological variables downwind of layer poultry houses and the application of an inverse Gaussian plume model. Atmospheric NH3 concentrations and deposition fluxes across the study landscape were studied at a resolution of 25 m x 25 m. The approach combined a detailed landscape inventory of all farm activities providing high resolution NH3 emission estimates for atmospheric dispersion modelling and an intensive measurement programme of spatial NH3 concentrations for verifying modelled NH3 concentrations. The spatially diverse emission pattern resulted in a high spatial variability of modelled mean annual NH3 concentrations (0.3 to 77.9 μg NH3 m-3) and dry deposition fluxes (0.1 to >100 kg NH3-N ha-1 yr-1) within the landscape. Annual downstream fluxes and variation in spatial concentration of dissolved inorganic nitrogen (NH4 + and NO3 -) and dissolved organic nitrogen (DON) were studied in the two main catchments within the study landscape (agricultural grassland vs. semi-natural moorland catchment). The grassland catchment was associated with an annual downstream total dissolved nitrogen (TDN) flux of 14.4 kg N ha-1 yr-1, which was 66% higher than the flux of 8.7 kg ha-1 yr-1 from the moorland catchment. This difference was largely due to the NO3 - flux being one order of magnitude higher in the grassland catchment. The contribution of DON to the TDN flux varied between the catchments with 49% in the grassland and 81% in the moorland catchment. Fluvial and atmospheric N fluxes were combined to derive N budgets of the two catchments. Agricultural activities accounted for the majority of N input to the catchments, with atmospheric deposition also playing a significant role, especially in the moorland catchment. Both catchments showed large stream export fluxes compared to their net import which suggests that their capacity of N storage is limited. This thesis quantifies major N fluxes in a study landscape and shows their large spatial variability. Agricultural activities dominate landscape N dynamics. The work demonstrates the importance of considering landscape N variability when attempting to reduce the environmental impact of agricultural activities.

Nitrogen (N) is known to be a limiting factor in peatlands and as such, the vegetation present has adapted to living in low N conditions. This makes such ecosystems particularly vulnerable to increases in the deposition of reactive N (Nr), which may result in significant changes to its biodiversity and biogeochemistry. Since the industrial revolution, the amount of anthropogenic Nr globally has increased from ~15 Tg N y-1 in the 1860’s to ~187 Tg N y-1 in 2005, and is estimated to reach ~267 Tg N yr-1 by 2050 (Galloway et al. 2004, Galloway et al. 2008). Consequences include acidification, loss of biodiversity, changes in vegetation, N-saturation, eutrophication, health impacts and the release of greenhouse gases.Objectives of this thesis were (i) to measure key components of the N-budget at Auchencorth Moss, a Scottish moorland, for a two year period (Jan 2009 – Dec 2010) and (ii) to compare current deposition rates with those measured 14/15 years previously. Annual fluxes of N inputs were estimated from measurements of wet only deposition, estimates of N-fixation deposition and from atmospheric deposition modelled from hourly concentrations of N containing gases and aerosols. Exports were estimated from stream measurements and from atmospheric emissions modelled from hourly concentrations. Organic N is often an underreported part of the N-cycle, but the results presented here suggest it is an important part of the N story. An attempt to identify (dissolved organic nitrogen) DON compounds in both precipitation and stream water was made using GC×GC-NCD. Ten unique compounds were detected, of which only five could be identified: pyrrole, benzonitrile, dodecylamine, N-nitrosodipropylamine and decylamine. Pyrrole, benzonitrile and three unknown compounds were present in both precipitation and stream samples. Ammonia (NH3) fluxes were measured over a 7 month period in 2009 using a wet-chemistry gradient system with online analysis and calculated with the aerodynamic gradient method. The results were used to refine a bi-directional dynamic exchange model. Several parameters were updated, including an increased stomatal emission potential from 180 to 350, a reduction of the minimum cuticular resistance (Rw,min) used to calculate Rw from 20 s m-1 to 15 s m-1 and an increase in the leaching rate (Kr¬) from the leaf surfaces from -0.01 to -0.1 s-1. The exchange parameterisations used to estimate HNO3, HONO and the aerosol compounds were taken from the literature and earlier studies at the site.Overall, Auchencorth was found to accumulate N, with deposition exceeding export by -1.61 kg N ha-1 yr-1. The main N deposition was from NH3, followed by wet deposition of ammonium. DON, which is not routinely included in N budgets, contributed 6.5% of total deposition. The largest loss of N was as DON via the stream with N losses of -5.31 kg N ha-1 yr-1 or 71.8% of total export. Between 1995 and 2009/2010, deposition decreased by 0.81 kg N ha-1 yr-1, with the wet deposition of inorganic nitrogen decreasing by 25.2%, but dry deposition increasing by 12.5%. DON, N2O and N-fixation were not included in the comparison as they were not measured in 1995.This thesis has demonstrated that DON is an important parameter in the overall N budget, and should be routinely measured when assessing the N status of ecosystems.

The nitrogen budgets of Eurotia lanata (Pursh.) Moq. and Atriplex confertifolia (Torr. and Frem.) S. Wats salt desert shrub plant communities were investigated. In each, a complete biomass and organic nitrogen inventory was made. In addition, investigations of the nitrogen fixation potential of soil surface microflora and inorganic soil nitrogen relationships were carried out. Greater total biomass and organic nitrogen was found in the above-ground portions, annual shoot productivity, and litter of the Atriplex community. However, the Atriplex community was exceeded by the Eurotia community in root biomass. Roots accounted for 74 and 87 percent of the plant biomass and 83 and 90 percent of the associated organic nitrogen in Eurotia and Atriplex communities respectively. Root biomass distribution at various depths was markedly different in the two communities. Differences between communities in relative amounts of various plant parts and litter are related to contrasting plant growth habit, and differences in soil texture and soil salinity. Total plant biomass estimates, which were 18,480 and 17,300 kilograms per hectare for Eurotia and Atriplex communities, were not significantly different and reflect the overriding influence of macroclimate and associated moisture limitation. Under laboratory conditions the soil surface microflora of the Atriplex community was able to fix significant amounts of atmospheric nitrogen while that of the Eurotia community did not. Nitrogen fixation potential in the Atriplex community was associated with the presence of abundant lichen cover and associated heterocvstcontaining blue-green algae of lichen interspaces. Differences between communities were found in rates of mineralization, downward flux, and pattern of utilization of inorganic soil nitrogen. Soil salinity appeared to strongly limit inorganic soil nitrogen mineralization as well as root growth and nitrogen uptake in the lower part of the Atriplex soil profile; however, this lack of biological activity was compensated for by a greater downward flux of inorganic soil nitrogen from decomposing litter and surface soil in the Atriplex community. Shoot and root litter appears to be the most readily available source of inorganic soil nitrogen for plant growth in salt desert shrub plant communities.

Red Alder (Alnus rubra) is a native coastal hardwood in British Columbia and has evolved a symbiotic relationship with the nitrogen-fixing actinomycete, Frankia. This research uses δ15N signatures in soils, wood and litter to assess the contribution of nitrogen-fixing Red Alder to the components of stand nitrogen budgets. The stands used in this study are part of the B.C. Ministry of Forests’ long-term Experimental Project 1121.01 which examines the interactions between conifers and Red Alder. Planted in 1994, the Holt Creek site contains stands of Douglas-fir and Red Alder in five proportions (Red Alder: Douglas-fir proportions: 100/0, 50/50, 25/75, 11/89, 0/100). Increment cores from 5 trees per species per plot were taken along with soil and litter samples and analyzed for essential mineral elements and δ15N. I hypothesized that Red Alder would enhance soil nitrogen stocks and elevate δ15N signatures and that these changes would be observable in the δ15N signature of the tree rings of both species. Forest floor soil under Red Alder in the 100/0 plot was enriched in total nitrogen, and δ15N was elevated. This was due to the addition of nitrogen-rich litter, like followed by nitrogen discrimination in the forest floor during the process of nitrate leaching or denitrification. The litter of the two species did not differ in δ15N. The effect of forest floor nitrogen enrichment was visible in the tree rings of Douglas-fir in the 50/50 stand confirming that the effect of fixed-nitrogen can be observed in non-fixing species. Red Alder tree ring δ15N exhibited an unexpected non-linear relationship with time that could be due to reduced nitrogen fixation associated with declining tree vigour or negative feedback from low soil pH. This research provides insight into nitrogen fixation by Red Alder over time and its influence on pure and mixed stand nitrogen budgets. / Graduate / 2023-09-09

Sustainable tilapia production at Blue Ridge Aquaculture (BRA) is constrained by availability of high quality replacement water. I developed a pilot-scale wastewater treatment system to treat and reuse effluent presently discharged. An initial study was conducted to determine the response of the BRA waste stream to ozone application. Dosages of 6.9, 4.8 and 2.4 g O3 were applied for 30 minutes to 35 L of settled effluent. Optimum ozone dosage and reaction time, ozone transfer efficiency, ozone yield coefficient, degree of pollutant removal, and other ozone and water quality parameters were determined. Most results suggested that the maximum process feasibility limit for ozone contact time was approximately 9 minutes at an applied ozone concentration of 23g/m3 (6.9 g O3 dose). Formation of foam increased solids and COD removal up to three times. Poor removal or accumulation of DOC and TAN was observed, indicating the need for biological treatment following ozonation. Next, I evaluated a pilot station treatment train including sedimentation, microscreen filtration, fluidized bed denitrification, ozonation, aerobic biological oxidation in a trickling filter, and jar-test chemical flocculation. Significant improvements were found regarding solids, COD, cBOD5, NO3--N, TKN, and turbidity. Removal of foam after ozonation improved ozonation efficacy and pollutant removal. A nitrogen budget for the BRA facility was derived, indicating that 35% of the nitrogen applied in feed was assimilated in fish. I evaluated the possible impact of residual inorganic nitrogen forms from treated effluent upon fish in the recirculating systems. I found that less than 1% of the TAN produced would return the recovered stream, and that the existing biological contactors can remove it. Evaluation of TAN fate indicated that 84% was oxidized in biofilters, 14% was oxidized by passive nitrification, and 1% was removed by water exchange. For NO3-N, I determined that 56% was removed by passive denitrification and 44% by daily water exchange. The pilot station design was effective for removing organics and nutrients, and can serve as the basis for scale-up for treating and reusing the entire BRA effluent stream. / Ph. D.

No description available.

BORGES, David Araújo. Utilização de cepas de bactérias no cultivo intensivo de tilápia Oreochromis niloticus, sob sistema de renovação zero água. 2006. 50 f. : Dissertação (mestrado) - Universidade Federalç do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia de Pesca, Fortaleza-CE, 2006 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-12T13:03:29Z No. of bitstreams: 1 2006_dis_daborges.pdf: 228199 bytes, checksum: 33b54c2614fad5363ad43ae8d399c8d4 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-12T13:04:07Z (GMT) No. of bitstreams: 1 2006_dis_daborges.pdf: 228199 bytes, checksum: 33b54c2614fad5363ad43ae8d399c8d4 (MD5) / Made available in DSpace on 2016-07-12T13:04:07Z (GMT). No. of bitstreams: 1 2006_dis_daborges.pdf: 228199 bytes, checksum: 33b54c2614fad5363ad43ae8d399c8d4 (MD5) Previous issue date: 2006 / Control of water quality in intensive fish culture systems is offten the bottleneck for their successful operation. The most comon problems of water quality in those systems are related to oxigen depletion, organic matter and inorganic nitrogen accumulation, particularly ammonia. Bioaugmentation refers to the treatment of wastes or detrits using microorganisms, as an exemple nitrifing bacterias, which degradate undisareble substances in the system. The employment of bioaugmentation is becoming an option for recirculating fish cultures. Sugested benefits goes from inorganic nitrogen, phosfate and organic matter removal, to algae control in fish culture water. The aim of this experimental was to compare the intensive culture of tilapia Oreochromis niloticus with zero exchage water with and without biocultures introduction. The experiment consisted of 6 aquariums of 180L and nominal volume of 160L, separeted in two diferent treatments “A” and “Ex”; the first one the control grup and the second one the test. Those aquariums were stocked with juvenils of tilapia weiting 26,20 + 0,20g, and fed with 35%CP. During 35 days of culture none water have been chaged in the system Three times a week biocultures were introduced only on treatment “Ex”. Daily some físico – chemical parameters were collected like: pH, temperature and dissolved oxigen; and every week BOD,COD, total ammonia, nitite, nitrate, phosfate and chlorophyll “a” were analized from “A” and “Ex” treatments. For the experimental evaluation, besides those forementioned parameters, nitrogen budget, and some zootecnical index like: growth rate, food conversion rate and survival were utilized. Although “Ex” treatment has shown better results than “A” treatment, after a statistical analises we concluded that there were no diference between those two treatments / O controle da qualidade da água em sistemas intensivo de cultivo de peixes é, via de regra, um dos pontos críticos para o sucesso do supracitado sistema. Os problemas mais comuns de qualidade de água nos sistemas em questão estão relacionados com depleção do oxigênio dissolvido, acúmulo de matéria orgânica e nitrogênio inorgânico, particularmente amônia. Bioremediadores ou bioincrementação refere-se ao tratamento de poluentes ou detritos com o uso de microorganismos, como por exemplo, bactérias nitrificantes, as quais degradam as substâncias indesejadas no sistema. A utilização desta biorremediação vem sendo gradualmente aplicada em sistemas de recirculação. Os benefícios sugeridos vão desde a remoção de nitrogênio inorgânico, fosfato e matéria orgânica, a controle algal da água dos cultivos. O presente trabalho teve o objetivo de comparar o cultivo intensivo da tilápia Oreochromis niloticus, sob sistema de renovação zero de água, com e sem inóculo de cepas de bactérias. No experimento foram utilizados um total de 6 aquários com capacidade de 180L e volume nominal de 160L, divididos em dois tratamentos “A” (grupo controle) e “Ex” (grupo com inóculo bacteriano), neste ultimo sendo realizado 3 inoculações semanais de bactérias,em dias alternados. Os aquários foram povoados com juvenis de tilápia com peso médio de 26,20 + 0,20 g, tendo sido os mesmos alimentados, diariamente, com ração com 35% de PB. Durante os 35 dias de cultivo diariamente foram registrados valores de pH, temperatura e oxigênio dissolvido. Semanalmente foram realizadas análises de DBO, DQO, amônia total, nitrito, nitrato, ortofosfato e clorofila “a”. Para a análise do experimento, além dos parâmetros supracitados, foi utilizado um balanço de massa do nitrogênio e análise de índices zootécnicos como: crescimento dos indivíduos, fator de conversão alimentar e sobrevivência. Embora o tratamento “Ex” tenha apresentado melhores resultados nos parâmetros físico-químicos, no balanço de massa do nitrogênio e nos índices zootécnicos, não foi verificada diferença estatística entre os tratamentos “A” e “Ex”, a um nível de significância de 5%.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O controle da qualidade da Ãgua em sistemas intensivo de cultivo de peixes Ã, via de regra, um dos pontos crÃticos para o sucesso do supracitado sistema. Os problemas mais comuns de qualidade de Ãgua nos sistemas em questÃo estÃo relacionados com depleÃÃo do oxigÃnio dissolvido, acÃmulo de matÃria orgÃnica e nitrogÃnio inorgÃnico, particularmente amÃnia. Bioremediadores ou bioincrementaÃÃo refere-se ao tratamento de poluentes ou detritos com o uso de microorganismos, como por exemplo, bactÃrias nitrificantes, as quais degradam as substÃncias indesejadas no sistema. A utilizaÃÃo desta biorremediaÃÃo vem sendo gradualmente aplicada em sistemas de recirculaÃÃo. Os benefÃcios sugeridos vÃo desde a remoÃÃo de nitrogÃnio inorgÃnico, fosfato e matÃria orgÃnica, a controle algal da Ãgua dos cultivos. O presente trabalho teve o objetivo de comparar o cultivo intensivo da tilÃpia Oreochromis niloticus, sob sistema de renovaÃÃo zero de Ãgua, com e sem inÃculo de cepas de bactÃrias. No experimento foram utilizados um total de 6 aquÃrios com capacidade de 180L e volume nominal de 160L, divididos em dois tratamentos âAâ (grupo controle) e âExâ (grupo com inÃculo bacteriano), neste ultimo sendo realizado 3 inoculaÃÃes semanais de bactÃrias,em dias alternados. Os aquÃrios foram povoados com juvenis de tilÃpia com peso mÃdio de 26,20 + 0,20 g, tendo sido os mesmos alimentados, diariamente, com raÃÃo com 35% de PB. Durante os 35 dias de cultivo diariamente foram registrados valores de pH, temperatura e oxigÃnio dissolvido. Semanalmente foram realizadas anÃlises de DBO, DQO, amÃnia total, nitrito, nitrato, ortofosfato e clorofila âaâ. Para a anÃlise do experimento, alÃm dos parÃmetros supracitados, foi utilizado um balanÃo de massa do nitrogÃnio e anÃlise de Ãndices zootÃcnicos como: crescimento dos indivÃduos, fator de conversÃo alimentar e sobrevivÃncia. Embora o tratamento âExâ tenha apresentado melhores resultados nos parÃmetros fÃsico-quÃmicos, no balanÃo de massa do nitrogÃnio e nos Ãndices zootÃcnicos, nÃo foi verificada diferenÃa estatÃstica entre os tratamentos âAâ e âExâ, a um nÃvel de significÃncia de 5%. / Control of water quality in intensive fish culture systems is offten the bottleneck for their successful operation. The most comon problems of water quality in those systems are related to oxigen depletion, organic matter and inorganic nitrogen accumulation, particularly ammonia. Bioaugmentation refers to the treatment of wastes or detrits using microorganisms, as an exemple nitrifing bacterias, which degradate undisareble substances in the system. The employment of bioaugmentation is becoming an option for recirculating fish cultures. Sugested benefits goes from inorganic nitrogen, phosfate and organic matter removal, to algae control in fish culture water. The aim of this experimental was to compare the intensive culture of tilapia Oreochromis niloticus with zero exchage water with and without biocultures introduction. The experiment consisted of 6 aquariums of 180L and nominal volume of 160L, separeted in two diferent treatments âAâ and âExâ; the first one the control grup and the second one the test. Those aquariums were stocked with juvenils of tilapia weiting 26,20 + 0,20g, and fed with 35%CP. During 35 days of culture none water have been chaged in the system Three times a week biocultures were introduced only on treatment âExâ. Daily some fÃsico â chemical parameters were collected like: pH, temperature and dissolved oxigen; and every week BOD,COD, total ammonia, nitite, nitrate, phosfate and chlorophyll âaâ were analized from âAâ and âExâ treatments. For the experimental evaluation, besides those forementioned parameters, nitrogen budget, and some zootecnical index like: growth rate, food conversion rate and survival were utilized. Although âExâ treatment has shown better results than âAâ treatment, after a statistical analises we concluded that there were no diference between those two treatments