Northern peatlands represent a significant carbon reservoir, containing approximately a third of the terrestrial carbon pool. The stability of these carbon stores is poorly understood, and processes of accumulation and degradation appear to be finely balanced. Over the last decade, it has become increasingly clear that losses of dissolved organic carbon (DOC) from peatlands can be of considerable size and this flux appears to have increased substantially over the last 20 years. Despite its significance, the chemical composition of peatland-derived DOC remains poorly understood. This study aimed to characterise dissolved organic matter (DOM) at the molecular level using a novel combination of techniques. The study site (Cors Fochno, Wales, UK) is an ombrotrophic bog on which a number of studies into carbon cycling and hydrology have been carried out, providing a useful context for this project. The size and compositions of the DOC pool was monitored over 18 months, from three banks of piezometers, sampling from depths of 15 cm to 6 m. DOM which is representative of bog runoff was also monitored. DOC concentrations varied considerably between locations, spanning an order of magnitude (11.4 to 114 mgC l-1). Several relationships between DOC concentration and environmental and physical factors were established: DOC levels near the surface of the peatland varied with temperature, those in the runoff were most affected by recent rainfall events and the apparent DOC concentration at depth was related to the hydraulic conductivity of peat at that depth. The annual flux of DOC from the site was estimated at 113 tonnes, or 17.4 gC m-2. Only a small portion of the DOC pool could be characterised by analysis of dissolved combined amino acids (DCAA) and dissolved carbohydrates (as neutral sugars). Non-protein amino acids were most abundant in runoff samples, suggesting microbial reworking of DOM on entering drainage systems. DCAA yields decreased with depth, and the DCAA pool in deeper peat layers was characterised by more hydrophobic compounds. Interpretation of semi-quantitative results from TMAH thermochemolysis GC-MS analysis suggested oxidative degradation of organic matter near the surface of the peatland and photochemical degradation where DOM entered drainage networks, and this was supported by novel interpretation of results from ultrahigh resolution mass spectrometry analysis. The deepest porewaters were dominated by nalkanes, with notable contributions from fatty acids, suggesting a plant wax source for this DOM. The highest DOC concentrations were found at intermediate depth from a site midway between the centre of the bog and the southern boundary where hydraulic conductivities were low, and DOM from these piezometers were characterised by high contributions from a suite of phenolic compounds (with mainly para-hydroxyphenyl structures). These compounds have been linked to Sphagnum species, and are known to be functionally important to the development and maintenance of the unusual chemical environment in peatlands which slows decay rates, reduces microbial activity, and allows the sequestration of the large carbon reservoir. The findings of this study highlight the dynamic nature of peatland derived DOM, both in the size of the carbon pool and its composition which change dramatically with both season and depth.

The drinking water production in Sweden is facing challenges because of climatic changes, eutrophication and brownification, which contributes to an increase of algal blooms. This can lead to a production of different types of toxins, and the most common group of algal toxins is the hepatotoxic microcystins (MC). Other algal toxins that occur in Sweden are anatoxin-A (ATX-A) and the paralytic shellfish toxins (PST), which are neurotoxic. Flocculation and filtration has been shown to reduce intracellular MC, but to reduce extracellular MC it seems like other techniques are needed, such as membrane filtration, active carbon or ozone. It has also been shown that dissolved organic carbon (DOC) might affect the reduction of MC, either through occupying adsorption spots on the membrane, or through bindings between MC and DOC. In this project, the reduction of four types of added MC (microcystin-LR, microcystin-RR, microcystin-LY and (D-Asp3)microcystin-LR) with two nanofilters (NF) (with molecular weight cutoff (MWCO) 300-500 Da and 1000 Da) and one ultrafilter (UF) (MWCO 10000 Da) was studied. Further, the sorption between toxins and membrane or between toxins and DOC was studied. Water samples from three Swedish lakes were used to achieve a varying DOC-character. The reduction was also studied in synthetic water (MilliQ-water with adjusted pH and conductivity). This was done in order to study if the reduction was affected of the presence of DOC. The reduction of ATX-A and PST was studied in one experiment, with an NF-membrane (MWCO 1000 Da). The studied PST’s were saxitoxin (STX), N-sulfocarbamoyl-gonyautoxin-2 (C1) and Gonyuatoxin‑2 (GTX2). MC was reduced to under the limit of detection for all NF-experiments, while a low or no reduction was observed with UF. MC-RR was the toxin that, to the biggest extent, bound to the membrane or to DOC. MC seemed to bind to the membrane or to DOC to a higher extent when the DOC was hydrophilic and low molecular autochthonous, as compared to when the DOC was allochthonous. The reduction of ATX-A and PST was 20 – 40 %, with a reduction that declined during the experiment. C1, the PST with highest molecular weight and lowest net charge, was reduced to the lowest extent, while STX, the PST with the lowest molecular weight and the greatest net charge, was reduced to the highest extent. This implies that size exclusion was not a contributing reduction mechanism for ATX-A or PST, while electrostatic mechanisms probably were more important.

Soil carbon (C) is the largest terrestrial carbon pool. While inputs to this system are fairly well constrained, the diverse factors driving soil C efflux remain poorly understood. Carbon in surface soils is mobilized via two distinct pathways: CO₂ gas flux and dissolved C flux. The goal of this study was to quantify the role of hydrologic variability in mobilizing carbon as gaseous and dissolved fluxes from near-surface soils, and to determine their relative magnitudes. Data were collected through 2010 and 2011 from two subalpine sites in Arizona and New Mexico. I observed no significant variability in dissolved fluxes, and these values were low at all sites. In contrast, CO₂ fluxes were large (from 0.22 g C m⁻² d⁻¹ to 5.27 g C m⁻² d⁻¹) and varied between sites and between years. My results suggest that in arid montane forests soil carbon flux is critically linked to water availability.

This study combined concentration-discharge analyses (filtration at 0.45 m), cascade filtrations (at 1.2, 0.4, and 0.025 m) and asymmetrical flow field flow fractionation (AF4) to probe the influence of colloidal carriers (dissolved organic matter and inorganic nanoparticles) on observed concentration-discharge relationships for trace metals in a 155 ha forested catchment of the Santa Catalina Mountains Critical Zone Observatory (SCM CZO), Arizona. Many major elements (Na, Mg, Si, K, Ca) show no colloidal influence, and concentration-discharge relationships for these species are explained by previous work. However, the majority of trace metals (Al, Ti, V, Mn, Fe, Cu, Y, REE, U) show at least some influence of colloids on chemistry when filtered at the standard 0.45 m cutoff. Concentration-discharge slopes of trace metals with modest colloidal influence are shallow (approximate to 0.3) similar to that measured for dissolved organic carbon (DOC, 0.24), whereas elements with greater colloidal influence have steeper concentration-discharge slopes approaching that of Al (0.76), the element with the largest colloidal influence in this study (on average 68%). These findings are further supported by AF4 measurements that show distinct and resolvable pools of low hydrodynamic diameter DOC-sized material coexistent with larger diameter inorganic colloids, and the ratio of these carriers changes systematically with discharge because the DOC pool has a concentration-discharge relationship with shallower slope than the inorganic colloidal pool. Together these data sets illustrate that positive concentration-discharge slopes of trace metals in stream waters may be explained as the relative partitioning of trace metals between DOC and inorganic colloids, with contributions of the latter likely increasing as a result of increased prevalence of macropore flow.

Empirical studies have shown that algal- and detrital-based food web components are coupled in many pelagic systems as algal carbon enhances bacterioplankton production and growth efficiencies. Such phyto-bacterioplankton coupling impacts carbon flow through plankton food webs, yet the extent of coupling is poorly understood in systems receiving large amounts of allochthonous carbon. To investigate this issue, bacterioplankton abundance (BA) and community composition were compared to chlorophyll a concentrations and phytoplankton production in the tidal-freshwater James River (VA). BA averaged 107 cells mL-1 and was significantly related to chlorophyll a, phytoplankton production, and DOC concentrations. Analysis of DOC quality using fluorescence spectroscopy revealed that the fulvic DOC fraction was dominated by allochthonous compounds. However, estimates of DOC C:N and DOC turnover rates indicated that DOC was more labile in the lower part of the study reach where BA was highest. T-RFLP analysis of 16s rDNA showed that bacterioplankton community composition significantly varied between the upper and lower portions of the sampling reach. These findings suggest that coupling of food web components is an important pathway affecting carbon cycling within the tidal-fresh water James River.

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Submitted by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-07-13T18:49:27Z No. of bitstreams: 1 CamilleAnjosDissertacao2016.pdf: 1093173 bytes, checksum: 8ae404c119a9498adb807bd09db8731b (MD5) / Approved for entry into archive by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-07-13T18:49:44Z (GMT) No. of bitstreams: 1 CamilleAnjosDissertacao2016.pdf: 1093173 bytes, checksum: 8ae404c119a9498adb807bd09db8731b (MD5) / Made available in DSpace on 2017-07-13T18:49:44Z (GMT). No. of bitstreams: 1 CamilleAnjosDissertacao2016.pdf: 1093173 bytes, checksum: 8ae404c119a9498adb807bd09db8731b (MD5) Previous issue date: 2016-06-13 / This research, qualitative, aimed to verify the relevance of the playful in the formation of the pedagogue of Higher Education Institution (HEI) of the Distrito Federal and in the teaching profession in early childhood education and early years of elementary school to enhance the teaching process and full learning. To support theoretical way this research, we sought to understand the playful from its presence in culture, history and education over the years The playful was also regarded as objective activity, exposed in play and play and subjective, revealed as a state of wholeness. Turned up also the history of the formation of the pedagogue in Brazil, the playful presence in the teaching method of many educators and playful teacher training. As data collection instrument was used semi-structured interviews, document analysis and non-participant observation. Participated in the interviews 8 teachers, Faculty of Education graduates of HEI researched, the document analyzed were the Political and Educational Institutional Project, the Educational Project Course of Faculty of Education from the year 2008 and 2010. Three observations in classroom of teachers were made which also responded to the interview, two observations occurred in Early Childhood Education and a 3rd year in elementary school. Concludes that teachers consider important to work with the playful in their formative process, because in practice they need this element to make your student is interested in new knowledge and learn significantly, but the HEI has not considerable space so that the playfulness is a fundamental premise to be worked on teacher training. Indeed, in the teaching profession we determined the presence of playful teaching and the impact of this dimension in the process of teaching and learning. / Esta pesquisa, de natureza qualitativa, buscou verificar a relev??ncia do l??dico na forma????o do pedagogo de Institui????o de Ensino Superior (IES) do Distrito Federal e no exerc??cio da doc??ncia tanto na Educa????o Infantil quanto nos anos iniciais do Ensino Fundamental para potencializar o processo de ensino e aprendizagem integral. Para embasar de maneira te??rica esta pesquisa, buscou-se compreender o l??dico a partir de sua presen??a na cultura, na hist??ria e na educa????o ao longo dos anos. O l??dico tamb??m foi conceituado como atividade objetiva, exposta no jogar e no brincar e subjetiva, revelado como um estado de plenitude. Recorreu-se, ainda, ?? hist??ria da forma????o do pedagogo no Brasil, ?? presen??a do l??dico no m??todo de ensino de v??rios educadores e ao l??dico na forma????o de professores. Como instrumento de coleta de dados, foram utilizadas: entrevistas semiestruturadas, an??lises documentais e observa????es n??o participantes. Participaram das entrevistas oito professores egressos do curso de Pedagogia da IES pesquisada; os documentos analisados foram o Projeto Pol??tico-Pedag??gico Institucional (PPI) e o Projeto Pedag??gico de Curso (PPC), de 2008 e 2010, do curso de Pedagogia. Ademais, registraram-se tr??s observa????es em turmas de professoras que tamb??m responderam ?? entrevista ?????? duas na Educa????o Infantil e uma no 3?? ano do Ensino Fundamental. Constatou-se que os professores consideram importante o emprego do l??dico no processo formativo, pois, na pr??tica, eles necessitam deste elemento para despertar no estudante o interesse pelo novo saber, melhorando, assim, o aprendizado. No entanto, a despeito destas constata????es, a IES, muitas vezes, n??o abre espa??o para que o l??dico seja uma premissa fundamental para aprimorar a forma????o dos professores. Destarte, no exerc??cio da doc??ncia, foi poss??vel constatar a presen??a da did??tica l??dica e seu impacto positivo no processo de ensino e aprendizagem.

Excerpt: Blind from infancy, Arthel “Doc” Watson (1923-2012) was among the most acclaimed American roots musicians active during the second half of the 20th Century, and he remains influential and legendary in the 21st Century. A master of two acoustic guitar styles (flat-picking and finger-style) and highly skilled at playing old-time banjo and harmonica, Watson was also an expressive singer who possessed a resonant baritone voice and an extensive repertoire of traditional and contemporary songs.

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Pothole wetlands are ubiquitous throughout the Prairie Pothole Region and since 1900, 40-70% of potholes in the region have been drained to increase agricultural production. This thesis describes factors influencing spatial and temporal variations in wetland water quality and characteristics of drainage water. Research was conducted at Smith Creek watershed, southeastern Saskatchewan, where there has been controversy over recent renewed efforts to drain wetlands. Following snowmelt in 2009, 67 wetlands were sampled to determine whether spatial variations in wetland water quality were attributable to land cover, permanence classes, and surface drainage characteristics. Wetlands with cropped uplands had greater TP and K than wetlands with wooded and grassed uplands; TP, TDN, and DOC were higher in seasonally than permanently ponded wetlands; and salts were lower in wetlands with wooded uplands compared to wetlands with cropped and grassed uplands. Measurements of water quality of one permanently ponded wetland over a 20 week period in 2008 showed that the wetland acted as a solute trap. Variations in salts and DOC were influenced by hydrological processes such as runoff, evaporation, and shallow groundwater seepage, whereas variations in nitrogen, phosphorus, and bacteria were influenced by biotic, sorption, and hydrological processes. The experimental drainage of this wetland in November 2009 demonstrated that its water quality was an important control of drainage water quality. Further, the wetland ditch acted as a simple conduit, i.e., little solutes loss or gain occurred along it. In spring 2009, water quality along seven ditches and five natural connections that form between wetlands (termed spills) was compared. Concentrations of most solutes were similar, except TDN, DOC, HCO₃^-, K⁺, and Ca²⁺ that were higher in ditches than spills. Minimal changes in water quality along ditches and spills occurred, likely due to the low temperatures occurring in spring that restrict biotic processing and sorption. Notably, because ditches connect wetlands to streams, as opposed to spills that connect adjacent wetlands, ditches have a greater potential to contribute to downstream solute loading. Wetland drainage efficiency and wetland water quality were deemed the factors critical to determining solute exports via ditches. Results of wetland water quality and drainage characteristics can be useful to future modeling exercises and could be used to inform wetland drainage practices and policies.