In order to delineate the potential sources and to understand the main controls on the biogeochemical cycling of dissolved and particulate organic matter (DOM, POM) and dissolved inorganic nitrogen (DIN) during estuarine mixing, comprehensive seasonal geochemical and isotopic and surveys across the freshwater-tidal interface were carried out in the Tyne and Tweed Estuaries, NE UK. This study provided a contrast between a relatively pristine system (Tweed) with one that is heavily influenced by anthropogenic activity (Tyne). Geochemical and isotopic (13C, 14C and 15N) analyses demonstrated the predominance of terrigenous organic matter in both these estuaries, with elevated river discharges leading to enhanced terrestrial loading. High pCO2 values in the Tyne (summer) and Tweed (winter) suggested that a significant fraction of this terrestrially-derived organic matter (both DOM and POM pools) is relatively labile and can potentially undergo significant mineralization during estuarine mixing. In both estuaries in situ processing of DIN was relatively minor, with mixing between different sources being the main factor in controlling the distribution of nitrate and ammonium across the salinity gradient. However, anthropogenic ammonium discharges in the Tyne were found to have an enormous direct and indirect impact on estuarine nitrogen cycling. Large, concave removals of terrigenous high molecular weight (HMW) DOC caused by flocculation, biodegradation, and/or photochemical oxidation were associated with a non-conservative 13C-enrichment in d13C signatures. Radiocarbon dates showed an export of young (modern) HMW DOC and old (100-1000s of years), terrigenous POC to the North Sea. 14C-enriched values in coastal North Sea HMW DOC were attributed to anthropogenic discharges originating from within the coastal North Sea environment. In the Tweed, seasonal changes in soil characteristics resulted in an older age for POM during the summer. In the Tyne, decreases in POC% with increasing salinity sometimes coincided with an increase in POC age. This was attributed to mixing with older sediment and to the possible preferential loss of the younger, more labile POC fraction during mineralization. This study has shown that land use patterns, sewage inputs, and freshwater flushing time are the main influences in determining the behaviour and origin of organic matter and DIN entering the coastal North Sea in these two systems.

The purpose of this research is verified the concentration of particulate matter in the principals streets and avenues of Centro district of Santa Maria city/RS, making an association between geoecological conditions and the local urban structure. The specifics purposes are (a) make a zoning of Centro district s principals streets and avenues with their deposition potential of particulate matter. (b) Estimate the quantity of particulate matter emitted and its temporal variation through the years studied. (c) Quantified the bus fluxes in the streets and avenues researched, and others streets that have a significance flux; therefore a mapping of the principals traffics rote in the Center neighborhood can be made. (d) Correlate the occurrence of the principals atmospheric weather s type with the particulate emissions index stocked in FEPAM/RS s data basis. The research methodology was characterized for the environmental zoning s elaboration in the Centro district with focus on the air's quality. Lately, an investigation of particulate matter was made, using field work and secondary data related to inhale particulate matter, consulted in FEPAM/RS. The third stage consists in an intersection between particulate matter s data and the zoning map, with the intention of establish possible correlations and test the environmental zoning s efficiencies. The last stage consists in analyses the datas intersectioned relative to particulate matter concentrations suitable with what was pre-establish in the environmental zoning. Was verified that if the depositions were very differenced accordant to local collection, therefore, it wasn t possible to establish one relation that evidences the depositions level with the year s period. The investigation of the relation between inhalable particulate matters and habitual succession of atmospheric weather s type, it demonstrated the existence of a big correlation of day s concentration number up to 50 μg/m³ with winter s mouths for Santa Maria city. For this case we can say that the vehicles fluxes consisted in the principal factor that collaborated to air s quality deterioration. / O objetivo dessa pesquisa é o de verificar a concentração de material particulado nas principais ruas e avenidas do bairro Centro de Santa Maria/RS, relacionando, como variáveis de influência, as condições geoecológicas e a estrutura urbana local. Os objetivos específicos buscam: (a) Realizar um zoneamento das principais ruas e avenidas do bairro Centro quanto ao potencial de deposição de material particulado; (b) Estimar a quantidade de material particulado emitido, e sua variação temporal ao longo do ano; (c) Quantificar o fluxo de ônibus nas ruas e avenidas pesquisadas e demais ruas de fluxo significativo, estabelecendo um mapeamento das principais rotas de tráfego (d) Correlacionar a ocorrência dos principais tipos de tempo atmosférico com os índices de emissões de particulados armazenados na base de dados da Fepam/RS; (e) Realizar um mapeamento da vegetação no bairro Centro, em escala de detalhe, buscando estabelecer a correlação entre a cobertura vegetal existente e a quantidade estimada de emissão de material particulado. A metodologia de pesquisa caracterizou-se pela elaboração de um zoneamento ambiental do bairro Centro com enfoque na qualidade do ar. Posteriormente realizou-se a busca das concentrações de material particulado, em trabalho de campo, e dados secundários referentes ao material particulado inalável extraídos da FEPAM/RS. A terceira etapa consistiu no cruzamento dos dados de material particulado com o mapa de zoneamento, com vistas a estabelecer possíveis correlações e, também, testar a eficácia do zoneamento ambiental no que se refere à qualidade do ar. A última etapa consistiu na análise e cruzamento dos dados referentes às concentrações de material particulado e a sucessão habitual dos tipos de tempo em Santa Maria/RS. Constatou-se que grande parte das ruas e avenidas demonstraram quantidades de particulados condizentes com o que foi pré-estabelecido no zoneamento ambiental. Verificou-se que as deposições foram bem diferenciadas conforme o local de coleta, não sendo possível estabelecer uma relação que evidencie nível de deposição com período do ano. A investigação da relação entre as concentrações de material particulado inalável com a sucessão habitual dos tipos de tempo, demonstrou a existência de uma grande correlação quanto ao número de dias de concentração acima de 50μg/m³ com os meses de inverno para a cidade de Santa Maria. De maneira geral, pode-se dizer para o caso da cidade de Santa Maria, o fluxo de veículos constitui-se no principal fator de contribuição na deteriorização da qualidade do ar.