Meadow bromegrass (<i>Bromus riparius</i> Rehm.) is a recently introduced pasture grass in western Canada. Its leafy production and rapid regrowth have made it the most widely used grass species for pasturing beef animals in this region. As relatively little breeding work has been done on this species, there is little information on its breeding behaviour. The main objective of this study was to estimate genetic parameters and assess breeding methodologies for meadow bromegrass. Forty-four meadow bromegrass genotypes from the three available cultivars and forty half-sib (polycross (PX) and open-pollinated (OP)) and selfed (S1) progenies were evaluated for morphological and agronomic characters, and molecular (RAPD) markers. Genetic variation for total biological yield, head weight, seed yield, harvest index, height, growth habit, spread, and volume was significant in the OP and S1 tests. Genetic variation estimates for dry matter yield were negative (PX), not significant (OP), or moderate (S1). Estimated geneticvariation for quality traits and those characters which were visually evaluated was not significant, except for growth habit (OP and S1) and acid-detergent fiber (ADF) (S1). Among progeny lines, RAPD marker variation found in the half-sib progenies accounted for about 15% of the total variation. In the S1 test the variation among progeny lines was twice that of the half-sib progenies. Correlations between the different characters demonstrated that is possible to simultaneously improve both seed and forage yield. Since leafiness was found to be correlated with dry matter yield but not with seed yield it may be possible to simultaneously improve all three characters. Rankings of progenies by the half-sib tests for forage and seed yield were not changed by the use of the synthetic parental value (SVi) which includes information from selfed progeny. The PX progeny test did not discriminate parents as well as the OP and S1 tests, which may be due to non-random pollination in the polycross. The S1 progeny test showed the highest predicted response to selection, followed by the OP test. Heritability estimates from the OP and S1 tests for total biological yield, seed yield, harvest index, and height, were similar to those found in the clonal evaluation test. Therefore, a clonal evaluation test will provide sufficient information to choose parents for breeding an improved synthetic cultivar for these characters. Observed dissimilarity of ranking of progeny lines over progeny tests for some traits (head weight, seed yield, and harvest index) was due to discrepancies between the PX and OP tests. No differences in progeny line ranking among the progeny tests were observed for all other traits. Analysis of variance on marker frequency means showed that interaction between genotypes and progeny lines was also not significant.

Resumo: Objetivou-se avaliar características fisiológicas da leguminosa forrageira tropical, Macrotyloma axillare cv. Java (macrotiloma) submetida a diferentes potenciais hídricos e determinar a qualidade fisiológica de três lotes de sementes dessa cultivar. Determinou-se a pureza física dos lotes, o peso de mil sementes, o teste padrão de germinação (TPG) e o índice de velocidade de germinação (IVG). Os seguintes testes de vigor foram realizados: primeira contagem do TPG, condutividade elétrica e envelhecimento acelerado. Avaliou-se o efeito da disponibilidade hídrica do substrato sobre a germinação de sementes com o uso de soluções de Polietileno Glicol (PEG 6000) e a germinação e o crescimento inicial das plântulas sob diferentes disponibilidades hídricas no solo (60, 45 e 35% da capacidade de campo). Diferenças no potencial fisiológico inicial de sementes escarificadas puderam ser observadas pelo teste de germinação. Os testes de primeira contagem e IVG não foram sensíveis para detectar diferenças no potencial fisiológico das sementes dos três lotes estudados. O envelhecimento acelerado das sementes escarificadas pode ser realizado a 41º C por um período mínimo de 72 horas ou a 45º C durante 48 horas. O teste de condutividade elétrica mostrou-se adequado para diferenciar os lotes de sementes escarificadas, a partir de 48 horas de embebição. O lote 3 foi classificado como o lote de menor vigor. Houve redução progressiva e significativa da porcentagem de germinação e do IVG quando o potencial hídrico do substrato decresceu de 0,0 até -0,6 MPa e decréscimo na germinação e no IVG quando a disponibilidade hídrica no solo decresceu de 60% para 45 e 35% da capacidade de campo. Todas as características da parte aérea das plântulas foram prejudicadas pela redução da disponibilidade hídrica do solo, notadamente, os parâmetros altura de plântula,... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this research was to evaluate physiological characteres of the tropical forage legume, Macrotyloma axillare cv. Java (perennial horse gram) submitted to different water potentials and to determine the physiological quality of three seed lots of this cultivar. The physical purity, 1000 seeds weight, standard germination test (SGT) and speed of germination index (SGI) were evaluated. The following vigour tests were performed: first count of SGT; electrical conductivity and accelerated aging. The effect of substratum water availability was studied using polyethylene glicol solutions (PEG 6000) on seed germination and soil with three levels of water contents (60, 45 and 35% of field capacity) on germination and early growth of seedlings. Differences on initial physiological potential of scarified seeds could be observed by the germination test. First count of germination and SGI were not sensible to detect differences in seed physiological potential of these three lots. The accelerated aging of scarified seeds can be performed at 41ºC during at least 72 hours or at 45ºC for 48 hours. The electrical conductivity test was adequate to differentiate lots of scarified seeds after 48 hours of imbibition. The seed lot number three was classified as the lowest vigour lot of perennial horse gram seeds. There was progressive and significant decrease of germination percentage and of SGI when the substratum water potential decreased from zero to -0,6 MPa and reduction of germination percentage and SGI when the soil water availability decreased from 60% to 45 and 35% of field capacity. All seedlings shoot characters were hastened by the decrease of soil water availability, mainly the parameters: seedling height, fresh mass and area of leaves... (Complete abstract, click electronic access below) / Orientador: Teresinha de Jesus Deléo Rodrigues / Coorientador: Antônio João Cancian / Banca: Paola Pedroso Vantini / Banca: Ana Regina Pimentel de Almeida / Banca: Izabel Cristina Leite / Banca: Maria Lidia Stipp Paterniani / Doutor

Made available in DSpace on 2014-06-11T19:30:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-03Bitstream added on 2014-06-13T19:00:12Z : No. of bitstreams: 1 fernandes_khp_me_botfca.pdf: 390066 bytes, checksum: fb96e0ea61ad34618a964b5ff8e55716 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O pinhão manso (Jatropha curcas L.) é uma espécie perene com grande potencial para produção de biodiesel, pois apresenta rápido crescimento é de fácil cultivo e com capacidade de adaptação às diversas condições edafoclimáticas. O presente trabalho tem como objetivo avaliar, por meio de teste de progênies, a variabilidade genética de progênies de pinhão manso para as características de crescimento: altura, diâmetro do colo e número de ramos. Foi implantado um teste de progênies na Fazenda São Manuel, localizada no município de São Manuel - SP, pertencente à Faculdade de Ciências Agronômicas, UNESP, Campus de Botucatu. O espaçamento utilizado foi de 4,0 x 2,5 m, em blocos casualizados. Foram analisadas altura, diâmetro da base e número de ramos das plantas de 28 progênies, procedentes principalmente da EPAMIG, e obtidas às estimativas de parâmetros genéticos. As médias de altura e diâmetro foram aos seis meses de 52,38 e 2,91, aos 12 meses 68,87 e 3,98, aos 18 meses 82,31 e 4,23 e aos 24 meses 108,78 e 5,04, respectivamente. Detectou-se diferença estatística pelo Teste F, em nível de 5% de probabilidade, indicando haver variabilidade entre as progênies. As estimativas dos coeficientes de variação genética individual (CVgi) e coeficiente de variação genética de progênies (CVgp) aos 24 meses foram de 26,7 e 13,4% para altura; 15,1 e 7,5% para diâmetro e 21,2 e 10,6% para número de ramos, respectivamente. As estimativas de herdabilidade média de progênies () aos 24 meses foi de 0,36 para altura; 0,35 e para diâmetro e 0,42 para número de ramos, respectivamente. Os resultados obtidos indicam que as progênies de pinhão manso apresentam variabilidade genética para os caracteres avaliados, mostrando potencial para serem utilizadas em programas de melhoramento genético / The jatropha (Jatropha curcas L.) is a perennial species with a great potential for biodiesel production, as it offers rapid growth, moreover it is easy to be cultivated and it has a high capacity of adaptability to various soil and climatic conditions. The objective of this research is to evaluate, by progeny test, the genetic variability for the following characteristics of jatropha’s progenies; growth, height diameter and number of branches. It has been implanted a progeny test, at São Manoel’s farm, located in São Manoel - São Paulo, belonging to the Faculdade de Ciencias Agronomicas, UNESP, Botucatu. The experimental design was random blocs 4,0 x 2,5 m. The project analyzed height, diameter, number of branches of 28 progenies of plants, coming mainly from EPAMIG, and as a result the project obtained estimates of genetic parameters. The average height and diameter in the first six months were 52.38 and 2.91, at twelfth month were 68,87 and 3,98, at eighteenth month were 82,21 and 4,23 and at twenty-fourth month were 108,78 and 5,04. Statistical difference was detected by a F test at 5% level of probability, it indicates variability among the progenies. The coefficient estimates of individual genetic variation and genetic variation of progenies at twenty-fourth months were 26.7 and 13.4% for height, 15,1 and 7,5% for diameter 21.2 and 10.6% for number of branches, respectively. Estimates of heritability at twenty-fourth months were 0.36 for height, 0.35 for diameter and 0.42 for number of branches, respectively. The results obtained indicate that the progenies of jatropha present genetic variability for traits showing potential to be used in breedind programs

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-06-12T11:26:17Z No. of bitstreams: 1 2008 - Norberto Silva Rocha.pdf: 1212597 bytes, checksum: 348564fc2134bb9135658be25a94d180 (MD5) / Made available in DSpace on 2017-06-12T11:26:17Z (GMT). No. of bitstreams: 1 2008 - Norberto Silva Rocha.pdf: 1212597 bytes, checksum: 348564fc2134bb9135658be25a94d180 (MD5) Previous issue date: 2008-09-04 / Funda??o Carlos Chagas Filho de Amparo ? Pesquisa do Estado do RJ - FAPERJ / This research was carried on at Universidade Federal Rural do Rio de Janeiro, at DNAP/IZ, Forage and Pasture Department, Serop?dica, Rio de Janeiro State, Brazil. Four tropical forage legumes cultivation were assessed: (Calopogonium mucunoides (calopo), Pueraria phaseoloides (puero), Macrotyloma axillare (archer) and Neonotonia wightii (perennial soybean)) submitted under artificial increasing shade levels (0, 30, 50 and 70% shade) during rainy and dry seasons. Randomized blocks experimental design with four replications and 4x4 factorial arrangement was performed. The qualitative variable (species) by SNK test at 5% probability as well as the quantitative one (shade) by regression statistic analysis were evaluated. The estimated parameters were: dry matter production (DMP), crude protein level (CP), crude protein production (CPP), neutral detergent fiber (NDF), cellulose (CEL), hemicellulose (HEM) and lignin (LIG), leaf/steam ratio (RL/S) and also mineral composition (calcium (Ca), phosphorus (P) and potassium (K)). Puero and the archer presented the biggest PMS during rainy and dry season, respectively. Gains on legumes DMP according to increasing shade levels during both evaluation periods were observed. Exclusively during rainy season, highest DMP under 30% shade level was presented by calopo. The puero and the archer presented bigger PMS while submitted to 50% shading treatment, during both evaluation periods. At 70% in rainy season as at 50% in dry one, highest DMP by perennial soybean was demonstrated. The biggest CP contents were observed by puero species and perennial soybean in both evaluation periods. For the CP content, only during dry season an increment has been seen according to the shading levels. The biggest CPP has been observed with the puero on the rainy season and with the archer on the dry one. The smallest and biggest NDF and CEL contents were observed with the species calopo and puero, respectively, during rainy seasons. On this evaluation the HEM and LIG contents did not varied (P>0.05) among legumes. During dryness, perennial soybean presented lowers NDF, CEL and HEM contents, while the biggest contents were observed on puero. For the shading levels purpose, it has been observed an increase on the NDF, CEL and HEM contents with the shading improvement on both evaluation seasons. No effect on LIG were observed on species or shading levels, during both seasons. Calopo and perennial soybean presented bigger RL/S on the rainy season and during the dry one bigger RL/S was shown with the perennial soybean. Regarding shading effects over RL/S values, a reduction related to studied treatments have been observed. For the mineral composition there was no difference on the Ca and P contents for the legumes focused on this study, however a lower K content was got by archer during rainy season. On dry season, the Archer obtained bigger P content and lower Ca and K ones. No difference on P and K contents for puero and perennial soybean legumes. A bigger Ca content was obtained by perennial soybean during that time. The increasing shading levels leads to increments on Ca, P and K contents, during both evaluated periods. Under an intensified shading level the biggest increase was observed on the studied minerals. Nevertheless, the best result for the tropical forage legumes cultivation, submitted to different shading levels, was presented on the 50% shade level, where the biggest DMP concentration, intermediate gains in fiber composition and increment to the forage have occurred under this condition. / O experimento foi conduzido na Universidade Federal Rural do Rio de Janeiro, no Setor de Forragicultura e Pastagem do DNAP/IZ, Serop?dica, RJ. Foi estudado o cultivo de quatro leguminosas forrageiras tropicais (Calopogonium mucunoides (calopog?nio), Pueraria phaseoloides (kudzu tropical), Macrotyloma axillare (macrotiloma) e Neonotonia wightii (soja perene)) submetidas a n?veis de sombreamento artificiais (0, 30, 50 e 70% de sombra), durante os per?odos das ?guas e seca. O delineamento experimental foi em blocos ao acaso com esquema fatorial 4x4, com quatro repeti??es. A vari?vel qualitativa (esp?cie) foi estudada utilizando-se o teste SNK a 5% de probabilidade, e a vari?vel de car?ter quantitativo (sombreamento) foi avaliada por meio de an?lise de regress?o. Os par?metros avaliados foram: produ??o de mat?ria seca (PMS), teor de prote?na bruta (PB), produ??o de prote?na bruta (PPB), a composi??o da fra??o fibrosa (fibra em detergente neutro (FDN), fibra em detergente ?cido (FDA), celulose (CEL), hemicelulose (HEM), lignina (LIG)), a rela??o folha/haste (RF/H) e a composi??o mineral: c?lcio (Ca), f?sforo (P) e pot?ssio (K). O kudzu tropical e o macrotiloma apresentaram as maiores PMS durante os per?odos das ?guas e seca, respectivamente. Foram observados incrementos na PMS das leguminosas estudadas em fun??o dos n?veis de sombreamento, durante os dois per?odos de avalia??o. O calopog?nio apresentou maior PMS sob o n?vel de 30% de sombra, sendo somente avaliado no per?odo das ?guas. O kudzu tropical e o macrotiloma apresentaram maior PMS quando submetidas ao tratamento de 50% de sombreamento, durante os dois per?odos de avalia??o. A soja perene apresentou maior PMS sob o n?vel de 70% na ?poca das ?guas e no tratamento de 50% no per?odo seco. Os maiores teores de PB foram obtidos pelas esp?cies kudzu tropical e soja perene nos dois per?odos de avalia??o. Para o teor de PB, somente durante o per?odo seco foi observado incremento em fun??o dos n?veis de sombreamento. A maior PPB foi observada para o kudzu tropical na ?poca das ?guas e para o macrotiloma na ?poca seca do ano. Os menores e os maiores teores de FDN e CEL foram observados nas esp?cies calopog?nio e kudzu tropical, respectivamente, durante a esta??o das ?guas. Nesta avalia??o os teores de HEM e LIG n?o diferiram (P>0,05) entre as leguminosas. No per?odo seco, a soja perene apresentou os menores teores de FDN, CEL e HEM, sendo observado os maiores teores no kudzu tropical. Para o efeito dos n?veis de sombreamento, foi observado aumento no teor de FDN, CEL e HEM ? medida que o sombreamento foi intensificado, nos dois per?odos de avalia??o. N?o foram observados efeitos da esp?cie e dos n?veis de sombreamento para o teor de LIG, durante as duas esta??es do ano. O calopog?nio e a soja perene apresentaram maior RF/H na ?poca das ?guas e, durante a seca foi observado maior RF/H na soja perene. Quanto ao efeito dos n?veis de sombreamento sobre a RF/H foi observada redu??o nesses valores em fun??o dos tratamentos estudados, durante os dois per?odos de avalia??o. Quanto a composi??o mineral n?o houve diferen?a entre os teores de Ca e P para as leguminosas estudadas, entretanto o menor teor de K foi obtido pelo macrotiloma, durante o per?odo das ?guas. Na ?poca seca, o macrotiloma obteve maior teor de P e menores teores de Ca e K. N?o houve diferen?a entre os teores de P e K para as leguminosas kudzu tropical e soja perene. O maior teor de Ca foi obtido pela soja perene neste per?odo. Os n?veis crescentes de sombreamento acarretaram incremento nos teores de Ca, P e K, durante os dois per?odos avaliados. Sob o n?vel de sombreamento mais intenso foi observado o maior incremento dos minerais estudados. Contudo, a melhor resposta obtida para o cultivo de leguminosas forrageiras tropicais, submetidas a diferentes intensidades de sombreamento, foi apresentada sob o n?vel de 50% de sombra, onde concentraram maior PMS, acr?scimos intermedi?rios na composi??o fibrosa e incremento de minerais ?s forrageiras quando produzidas nessa condi??o.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-15T20:39:20Z No. of bitstreams: 1 monalisadeoliveiranascimento.pdf: 941297 bytes, checksum: 0ab9b6d24b97368a8b471da73b2ddc50 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T16:13:19Z (GMT) No. of bitstreams: 1 monalisadeoliveiranascimento.pdf: 941297 bytes, checksum: 0ab9b6d24b97368a8b471da73b2ddc50 (MD5) / Made available in DSpace on 2017-05-17T16:13:19Z (GMT). No. of bitstreams: 1 monalisadeoliveiranascimento.pdf: 941297 bytes, checksum: 0ab9b6d24b97368a8b471da73b2ddc50 (MD5) Previous issue date: 2012-09-05 / Estudos sobre saturação de espécies buscam conhecer o papel relativo de fatores locais e regionais sobre a estruturação das comunidades. No caso de comunidades zooplanctônicas, os resultados encontrados são bastante divergentes, tornando necessário o preenchimento de certas lacunas. Uma destas está na comparação entre diferentes tipos de ambiente, como perenes e temporários, que apresentam comunidades com características bem distintas. Lagoas temporárias passam periodicamente por eventos de seca e, considerando organismos aquáticos, este é um dos mais fortes distúrbios experimentados, pois impõe severas restrições fisiológicas e comportamentais. Baseado nestes fatos, este estudo tem como hipótese principal que lagoas temporárias apresentam comunidades zooplanctônicas insaturadas, enquanto lagoas perenes apresentam comunidades zooplanctônicas saturadas. Para testá-la, foi realizado um experimento em mesocosmos onde as comunidades zooplanctônicas destes dois tipos de lagoas foram manipuladas, bem como o evento de dispersão. Os resultados indicam que ambas apresentam-se saturadas e que, portanto, fatores locais são predominantemente mais importantes do que a dispersão (fator regional) sobre a estruturação destas comunidades. Dentre estes fatores locais, os fatores abióticos atuam como filtros selecionadores de espécies e parecem ser mais importantes do que as interações bióticas com as comunidades residentes. / Many studies about species saturation try to find out the relative role of the local and regional factors on the communities structure. Regarding to zooplankton communities, the results obtained are very divergent requiring the filling of certain gaps. One of these gaps is on the comparison between different types of environments, like perennial and temporary which have communities with very different features. Temporary ponds are periodically affected by drought events and, considering the aquatic organisms, this is one of the strongest disturbs that they experienced because it imposes physiological and behavioral restrictions. Based on these facts, the principal hypothesis of this study is that temporary ponds have unsaturated zooplankton communities while permanent ponds have saturated zooplankton communities. To test it, an experiment was made in mesocosms where the communities of both ponds were manipulated as well as the dispersion event. The results indicate that both communities are saturated and therefore local factors are predominantly more important than the dispersion (regional factor) on the structuring of these communities. Among these local factors, the abiotic factors act as species selectors filters and seems to be more relevant than the biotic interactions with the resident species.

Five subtropical perennial grass species, Cenchrus ciliaris, a Cynodon hybrid, Digitaria eriantha subsp. eriantha, Panicum maximum and Pennisetum clandestinum, were subjected to four levels of water availability in a small plot trial under a rainshelter during the summer growing seasons of 1996/97 and 1997/98. This work was carried out on the Hatfield Experimental Farm of the University of Pretoria, Pretoria, South Africa. The average yields for the tufted species (C. ciliaris, D. eriantha and P. maximum) were lower in the 1997/98 than the 1996/97 season. C. ciliaris, however, produced the highest average yields in both seasons. The average yields of the Cynodon hybrid and P. clandestinum (creeping grasses) reacted differently, in that the average yields were higher in the 1997/98 than 1996/97 season. The dry matter yields of all five grass species at slight water deficits, were not significantly different from yields under conditions of no water shortages, when the soil profile was brought to field capacity at the beginning of the growing season. The implication hereof is, that dry matter yields can be maintained, in conditions where slight water deficits occur, if there is some water stored in the soil profile. C. ciliaris, a notable drought tolerant species, produced yields (11.7-20.0 t ha-1) under non-control conditions (W1, W2 and W3) which were comparable to yields obtained from traditionally irrigated grasses such as the Cynodon hybrid (12.0-15.8 t ha-1) and P. clandestinum (5.6-11.8 t ha-1), under control conditions (W4). P.clandestinum, D. eriantha and P. maximum tended to be better adapted to wetter conditions, while the Cynodon hybrid was also able to produce good yields under both water limiting and non-limiting conditions. Water use efficiency, regardless of the grass species, tended to be better under non-control conditions. Grasses were thus able to produce more dry matter per unit of water under conditions where water became scarce. In vitro dry matter digestibility was not negatively affected by water scarcity, while crude protein content more often than not seemed to be better under control conditions. This could be due to the uptake meganism of nutrients, in which water plays a vital role. The number of stoma per unit area was more under control than water limiting conditions. The expression of the different structures on the leaf surfaces, were not altered by the level of water availability. In the absence of water shortages, the growth rates of C. ciliaris, D. eriantha and P.maximum, were almost twice those of the Cynodon hybrid and P. clandestinum, as measured at the end of two growth cycles in an irrigated field trial. In a pot trial, under glasshouse conditions, with C. ciliaris, the Cynodon hybrid and P.clandestinum, both the level of water availability, and the level of nitrogen were varied. Regardless of species and level of nitrogen, water was still used more efficiently under non-control conditions. Higher levels of nitrogen did, however, improve water use efficiency regardless of level of water available. As with higher levels of available water, higher levels of nitrogen also improved yields. In this trial, the Cynodon hybrid and C. ciliarisalso out-yielded P. clandestinum.<,/p> In summary it can be said that C. ciliaris and the Cynodon hybrid are adapted to warm growing conditions in producing high yields regardless of the level of water available. D. eriantha, P. maximum and P. clandestinum would produce better in such growing conditions if water was not as limiting. Regardless of the species, the plants were able to use water more efficiently under non-control conditions, while in Vitro digestibility was not negatively affected by water limiting conditions. Due to the uptake mechanism of nutrients, water limiting conditions may, however, decrease the crude protein content of the grass plants. Higher levels of nitrogen had a positive impact on dry matter yields and water use efficiency. / Thesis (PhD)--University of Pretoria, 2005. / Plant Production and Soil Science / unrestricted

>Magister Scientiae - MSc / Globally climate variability and anthropogenic effects are causing more perennial rivers to become non-perennial rivers. Non-perennial rivers are distinguished by their isolated pools which serve as refugia for aquatic organisms, water birds, and riparian vegetation. The literature on non-perennial rivers demonstrates that pools are poorly understood in terms of their location, nature, and geomorphic persistence. Therefore, this study examines the relationships between the spatial distribution, morphology, and substrate characteristics of pools in reaches of the Prins and Touws rivers in the Klein Karoo. A greater understanding of pools will facilitate better management, monitoring, and restoration strategies for pool ecology since the geomorphology of pools provides a key part of the ecological template. Worldview-2 satellite imagery (2017) and orthorectified aerial photography (2014, 2013, and 1944) were used to assess the effects of major flooding events on pools over time. A DGPS (Differential Global Positioning System) was used to survey the pool widths, lengths, depths, and valley widths, cross-sections, and longitudinal profiles of the river. Sediment samples and Wolman pebble counts were used to assess the grain size and organic matter content of each pool in the study area. Detailed descriptions of the characteristics of each pool in terms of position in the channel, valley form, and obstruction presence and type were also assessed. Results indicate that most of the large pools occur at bedrock outcrops of the valley margins, and smaller pools are associated with Vachellia karroo debris bar features. Larger and highly persistent pools are associated with valley confinement and smaller less persistent, scour pools occur mid-channel where the valley expands. Analysis of the results shows that the valley width is the dominant control on these forced pools. The type of obstruction also plays a role in the formation of the pool as large woody debris results in smaller pools whereas, bedrock outcrops result in larger sized pools. A significant relationship was found between the grain size and organic matter content of pools. Aerial photography of the spatial distribution of the pools revealed that before a major flood, the pools were small and patchy, whereas afterward, they were larger and more elongated. It is suggested that at the bedrock outcrops, major scouring and eddy processes drive the formation of larger pools during large flood events, whereas pool dissection by sediment deposits prevails during intervening intermediate to low flow periods. The results are discussed in terms of the geomorphic controls (valley width, pool dimensions, morphology, substrate, and obstruction characteristics) on the formation and maintenance of pools in dryland settings. A conceptual model is proposed to explain the geomorphic changes of the pools in the four geomorphological zones of non-perennial rivers.

Masters of Science / This study was conducted to investigate hydrogeochemical processes controlling the evolution of groundwater chemistry and their influence on water quality in the Heuningnes Catchment. The role or influence of hydrogeochemical processes in groundwater quality in aquifer systems remains poorly understood. One of the ways of improving such understanding is to employ different techniques to explore key processes that govern groundwater quality in aquifer systems. Therefore, the present study investigated hydrogeochemical processes of groundwater resources and identified key processes that explained its quality from a spatiotemporal perspective. The quantitative approach that provides the ability to assess relationships between variables both spatially and temporally was applied. Groundwater sampling was done on four occasions during July 2017, October 2017, March 2018, and July 2018. Identification of hydrogeochemical processes controlling the evolution of groundwater chemistry and quality was done using various complementary tools. These tools included classification of the main water types, evaluation of water-rock interaction by means of stoichiometry analysis and bivariate correlation plots, inverse geochemical modelling, and statistical analysis (hierarchical cluster analysis and factor analysis). Physical parameters were measured in situ, while water samples were collected from boreholes, piezometers, springs, and artesian boreholes for laboratory analysis for major ions analysis. Descriptive and bivariate statistical methods were used to summarise and evaluate the strength of the relationship between variables, while multivariate statistical methods were applied to group similar samples based on their chemical compositions. Tri linear Piper diagrams were generated to characterize water type based on double normalizing the proportions of cations and anions, while correlation and stoichiometric analysis were applied to identify hydrogeochemical processes influencing groundwater chemistry. The results generated from the trilinear Piper diagrams confirmed the dominance of sodium and chloride ions in waters of the Heuningnes Catchment. Groundwater of a Na/Cl type is typical for a coastal aquifer characterised by saline, deep ancient groundwater. The lower parts of the Catchment were characterised by saline groundwater. The results indicated that shallow groundwater samples within the study area were more mineralised as compared to deep groundwater with EC values ranging between 20.8 and 2990 mS/m, with waters within the Table Mountain Group region (TMG), recording the lowest values. Deep groundwater for boreholes and artesian boreholes located upstream in the Catchment was fresh and yielded some of the lowest EC values recorded with an EC value below 50 mS/m. Generally, EC values increased from the upper TMG region of the Catchment towards the Bokkeveld shale region downstream and were highest during the dry season of 2018. The results indicated strong geological influences on water chemistry. Bivariate correlation and stoichiometric analysis identified cation exchange, adsorption, evaporation, weathering of carbonates, sulphates and silicate minerals as processes influencing the chemistry of groundwater in the Heuningnes Catchment. The Saturation Index (SI) results showed a change of calcite, dolomite, aragonite, gypsum, anhydrite, halite, melantinterite, siderite and sylvite from being undersaturated to oversaturated at some areas for the different seasons along the flow path. The mass-balance modelling results indicated that ion exchange and reverse ion exchange processes were more dominant at low elevations along the same flow path during the dry periods. However, at high elevations along the flow path, silicate weathering was the dominant process taking place. The findings of this study demonstrated the influence of hydrogeochemical processes in changing the water chemistry along the flow paths. In conclusion, the study showed the value of utilising various assessment tools as complementary techniques to improve the understanding about hydrogeochemical processes, and its influence on evolution of groundwater chemistry and quality. Based on the findings of the study the following recommendations were made for future studies; the sample points or sample boreholes in the study Catchment should be increased; and to have more sampling trips to enable better comparison between the possible processes

As the climate is changing, there are clear impacts on the mass balance of glaciers. A glacier can be defined as the result of sufficient accumulation, in the form of snow and rain, compared to its ablation, the different types of glacial loss, a balance that then determines the size of the glacier. A phenomenon in glacial environments where processes and effects on the environment are still relatively unknown arethe so-called firn aquifers. Firn aquifers are a type of “glacial groundwater” where water seeps through the firn, a form of more compact snow, and then accumulates and forms masses of water on top of the more compact ice. These water reservoirs can then affect glacial hydrology, mass balance, and the ice dynamics in the area by acting as a buffer for the meltwater on the way to the sea, causing and intensifying hydrofracturing, lowering the glacier’s albedo as well as acting as a heat source which in turn can deform the underlying ice. In 2018 and 2019, Ground Penetrating Radar measurements were made on Lomonosovfonna, a glacier on Svalbard, to measure the position and water level of one of the glaciers’ firn aquifers. The purpose of this study is to compare the radar data with measured data of the snow and firn density (stake measured during 2012, 2014, and 2016 at three different locations) to see what effects the density profile has on the radar-derived depth measurements. For this, ArcGIS was used to plot the intersection points of 2018 and 2019, to compare the two year’s different depth to the underlying water table. Then, MATLAB was used with the stake measured density profile and interpolated with the calculated depth values with the same two-way travel time as the GPR data to correlate the depths to the same intersection points. The general result showed that the firn densityprofile did have an impact on the data, but not significantly enough to alter the overall values as the change between the two years are of the similar magnitude. There are many different variables that could have played a role in the achieved results and further research needs to be done in order to establish a more in-depth conclusion / När klimatet förändras finns det tydliga effekter på glaciärernas massbalans. En glaciär kan definieras som resultatet av tillräcklig ackumulering, i form av snö och regn, jämfört med dess ablation, de olika typerna av glaciärförlust, en balans som sedan avgör glaciärens storlek. Ett fenomen i glaciala miljöer där processer och effekter på miljön fortfarande är relativt okända är de så kallade firn akvifärerna. Firn akvifärer är en typ av "glacialt grundvatten" där vatten sipprar genom firnen, en form av mer kompakt snö, och sedan ackumuleras och bildar vattenmassor ovanpå den underliggande isen. Dessa lagringar av vatten kan sedan påverka glacialhydrologin, massbalansen och isdynamiken i området genom att bland annat fungera som en buffert för smältvattnet på väg mot havet, orsaka och intensifiera hydrofrakturering, sänka glaciärens albedo samt fungerar som en värmekälla som i sin tur kan deformera den underliggande isen. År 2018 och 2019 gjordes Georadar-mätningar på Lomonosovfonna, en glaciär på Svalbard, för att mäta positionen och vattennivån för en av glaciärernas akvifärer. Syftet med denna studie är att jämföra radardata med uppmätt data från snö- och firndensitet (uppmätt under 2012, 2014 och 2016 på tre olika platser) för att se vilka effekter densitetsprofilen har på radarhärledda djupmätningar. För detta användes ArcGIS för att plotta skärningspunkterna för 2018 och 2019 och att sedan jämföra de två årens olika djup med den underliggande vattenytan. Sedan användes MATLAB med den uppmätta densitetsprofilen, och interpolerades med de beräknade djupvärdena med samma tvåvägs-restid som GPR-data uppmätt för att korrelera djupen till samma skärningspunkter. Det allmänna resultatet visade att firn densiteten hade en inverkan på data, men inte tillräckligt signifikant för att ändra de övergripande värdena eftersom förändringen mellan de två åren är av samma storlek. Det finns många olika variabler som kunde ha spelat en roll i de uppnådda resultaten och ytterligare forskning behöver göras för att fastställa en mer djupgående slutsats.

Magister Scientiae (Integrated Water Resource Management) / River catchments in agricultural areas are strongly influenced by runoff from cultivated or grazed fields, and nutrient loading of these fields can result in large quantities of nitrates and phosphates being transported to rivers in surface runoff. In intensively farmed areas, nutrient loading is often so high that large quantities of nitrates and phosphates are transported to streams in surface runoff. Within these areas, strips of natural riparian vegetation and wetlands are critical in providing nutrient uptake functions that can reduce the load entering streams. A wetland can be a source, sink or transformer of nutrients, where fine sediments such as silt and clay have the ability to store and trap considerable amounts of phosphorus through adsorption and precipitation processes. Therefore, the determination of phosphorus adsorbed to fine sediment is important in understanding the role and value of wetlands in agricultural landscapes, and is the main focus of this study. The aim of the study is to evaluate an indicator-based approach, WET-EcoServices, to assess wetland sediment and phosphate trapping, through comparison with field survey data. The study focuses on spatial analysis and field survey of three Hydrogeomorphological (HGM) units classified for the Wiesdrift wetland on the Nuwejaars River, Cape Agulhas. The three HGM units are classified as: a floodplain wetland at the inlet of the system, a channelled valley-bottom wetland towards the middle part of the system and a floodplain wetland towards the outlet of the system. In-field observations were recorded for hydrogeomorphic and vegetation characteristics for each HGM Unit. AstroTurf mat sediment samples, grabbed channel bed and floodplain sediment samples were analysed for particle size and orthophosphate concentrations, while suspended sediment masses were recorded from three pairs of time-integrated sediment samplers located near the inlet, near the middle, and near the outlet of the wetland. Statistical analysis showed that orthophosphate concentrations are associated with fine sediment. Thus, the orthophosphate concentrations follow the distribution of silt on the Wiesdrift wetland. The dominant vegetation along transect 2, at which the highest concentrations of orthophosphate was found, is occupied by Typha capensis and Cyperus textilis. The percentage of fine sediment (silt) ranged between 0-37%, where the remaining percentage was sand. There was also a significant positive correlation between orthophosphate concentration and silt (Spearman’s rank-order correlation: rs = 0.692, N = 70, P < .001). The largest total sediment amount was found at Outlet 1 and Outlet 2 in the HGM unit 3 of the Wiesdrift wetland, with a value of 0.653 g. Overall, orthophosphate concentrations ranged between 0 mg/kg and 31320 mg/kg within the Wiesdrift wetland. WET-EcoServices determines an average score for phosphate trapping from on-site indicators such as hydrological zones, vegetation structure and soil texture/permeability. The dispersal of fine sediment and associated adsorbed phosphate is more complex than can be determined by a tool like WET-EcoServices because the tool captures the long-term mean conditions of a wetland system that determines the overall uptake of phosphates over extended time periods, thus future wetland assessments is recommended to take place over a longer period than this study. However, the field results of orthophosphate distribution are generally consistent with the findings from WET-EcoServices, further motivating for the use of the tool in wetland management applications.