abstract: Safe, readily available, and reliable sources of water are an essential component of any municipality’s infrastructure. Phoenix, Arizona, a southwestern city, has among the highest per capita water use in the United States, making it essential to carefully manage its reservoirs. Generally, municipal water bodies are monitored through field sampling. However, this approach is limited spatially and temporally in addition to being costly. In this study, the application of remotely sensed reflectance data from Landsat 7’s Enhanced Thematic Mapper Plus (ETM+) and Landsat 8’s Operational Land Imager (OLI) along with data generated through field-sampling is used to gain a better understanding of the seasonal development of algal communities and levels of suspended particulates in the three main terminal reservoirs supplying water to the Phoenix metro area: Bartlett Lake, Lake Pleasant, and Saguaro Lake. Algal abundances, particularly the abundance of filamentous cyanobacteria, increased with warmer temperatures in all three reservoirs and reached the highest comparative abundance in Bartlett Lake. Prymnesiophytes (the class of algae to which the toxin-producing golden algae belong) tended to peak between June and August, with one notable peak occurring in Saguaro Lake in August 2017 during which time a fish-kill was observed. In the cooler months algal abundance was comparatively lower in all three lakes, with a more even distribution of abundance across algae classes. In-situ data from March 2017 to March 2018 were compared with algal communities sampled approximately ten years ago in each reservoir to understand any possible long-term changes. The findings show that the algal communities in the reservoirs are relatively stable, particularly those of the filamentous cyanobacteria, chlorophytes, and prymnesiophytes with some notable exceptions, such as the abundance of diatoms, which increased in Bartlett Lake and Lake Pleasant. When in-situ data were compared with Landsat-derived reflectance data, two-band combinations were found to be the best-estimators of chlorophyll-a concentration (as a proxy for algal biomass) and total suspended sediment concentration. The ratio of the reflectance value of the red band and the blue band produced reasonable estimates for the in-situ parameters in Bartlett Lake. The ratio of the reflectance value of the green band and the blue band produced reasonable estimates for the in-situ parameters in Saguaro Lake. However, even the best performing two-band algorithm did not produce any significant correlation between reflectance and in-situ data in Lake Pleasant. Overall, remotely-sensed observations can significantly improve our understanding of the water quality as measured by algae abundance and particulate loading in Arizona Reservoirs, especially when applied over long timescales. / Dissertation/Thesis / Masters Thesis Sustainability 2018

Submitted by Secta BC (secta.csu.bc@uepb.edu.br) on 2017-03-21T19:32:20Z No. of bitstreams: 1 PDF - Rafaela Cristina de Souza Duarte.pdf: 17178678 bytes, checksum: bd68b4b71283d326a8bc5494f62f32d1 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2017-03-21T19:33:17Z (GMT) No. of bitstreams: 1 PDF - Rafaela Cristina de Souza Duarte.pdf: 17178678 bytes, checksum: bd68b4b71283d326a8bc5494f62f32d1 (MD5) / Made available in DSpace on 2017-03-21T19:33:17Z (GMT). No. of bitstreams: 1 PDF - Rafaela Cristina de Souza Duarte.pdf: 17178678 bytes, checksum: bd68b4b71283d326a8bc5494f62f32d1 (MD5) Previous issue date: 2014-02-26 / Mangroves have a mosaic of different habitats and microhabitats, each with their specific levels of complexity and occupied by different kinds of organisms. In this context, the present study aimed to assess the effect of habitat complexity and seasonality in the composition and structure of the invertebrate macrofauna associated with macroalgal species with different morphological characteristics. The research was conducted in the hypersaline mangrove of Tubarão River (5 o 04'34.87"S, 36 o 27'32.36"W), municipality of Macau, northern coast of the state of Rio Grande do Norte, Northeastern Brazil. Aiming to analyze the effect of habitat complexity on a local microhabitat scale and considering that the studied mangrove, due to their peculiar hipersalinity characteristics may harbor a rich fauna and flora, the following questions guide this research: a) Does the different macroalgae studied have different degree of habitat complexity? b) Macroalgae with different morphological characteristics supports invertebrate communities significantly different? c) Is there a relationship between habitat complexity and the composition, abundance and diversity of the invertebrate community of their phytal? and d) Is there difference between the pattern of abundance and composition of invertebrates found in macroalgal species between the dry and rainy seasons? A total of 1,750 individuals classified into five taxa were collected: Echinodermata, Amphipoda, Mollusca, Isopoda and Polychaeta, with 723 individuals found in the rainy season (associated with Gracilaria sp.) and 1,028 in the dry season (430 in Dictyota sp. and 598 in Solieria filiformes). Macroalgae of the dry period were morphologically distinct, however, the invertebrate fauna were not significantly different (p=0.1037), thus reinforcing that seasonality may have influenced the abundance and composition of macroinvertebrate taxa. The different macroalgae showed distinct morphological patterns and different degrees of habitat complexity, where more complex algae harbored a richer, abundant and diverse mollusc fauna. Specifically in the case of molluscs, species composition was typically marine, higher than other mangrove environments. Furthermore, the malacofauna was predominantly composed by micromolluscs, as adults whose sizes do not exceed 10 mm, and young individuals of species that reach a larger size. It is suggested that both habitat complexity as well as seasonality affect the richness, diversity and abundance of associated communities. In general, the marine macroalgae provides support for a variety of marine taxa, and may play an important role in increasing the structural underwater habitat complexity of mangrove systems. / Os manguezais apresentam um mosaico composto por diversos habitats e microhabitats, cada um deles com seus níveis de complexidade específicos e ocupados por diferentes tipos de organismos. Nesse contexto, o presente estudo tem por objetivo avaliar o efeito da complexidade do habitat e da sazonalidade na composição e estrutura da macrofauna associada a diferentes espécies de macroalgas com características morfológicas distintas. A pesquisa foi desenvolvida no manguezal hipersalino do Rio Tubarão (5º04 34,87 S; 36º27 32,36 O), município de Macau, litoral setentrional do estado do Rio Grande do Norte, Nordeste do Brasil. No intuito de analisar o efeito da complexidade do habitat em uma escala local de microhabitat e considerando que o manguezal estudado, devido à suas características peculiares de hipersalinidade podem abrigar uma rica fauna e flora, as seguintes perguntas nortearam esta pesquisa: a) As diferentes espécies de algas apresentam graus de complexidade de habitat distintos? b) Algas com características morfológicas diferenciadas suportam comunidades de invertebrados significativamente diferentes? c) Existe uma relação entre a complexidade do habitat oferecido pelas macroalgas e a composição, abundância, riqueza e diversidade de invertebrados participantes de seu fital? d) Existem diferenças entre o padrão de abundância e composição de invertebrados encontrados nas espécies de macroalgas entre os períodos seco e chuvoso? Foram coletados 1.750 indivíduos classificados em cinco taxa: Echinodermata, Amphipoda, Mollusca, Isopoda e Polychaeta, sendo 723 indivíduos encontrados no período chuvoso (associados à Gracilaria sp.) e 1.028 no período seco (430 em Dictyota sp. e 598 em S. filiformes). macroalgas apesar de serem morfologicamente distintas não apresentaram uma fauna de invertebrados significativamente diferente (p=0,1037), reforçando assim, que a sazonalidade pode ter influenciado a abundância e composição dos táxons de macroinvertebrados. As diferentes macroalgas apresentaram padrões morfológicos distintos e diferentes graus de complexidade de habitat, onde algas mais complexas abrigaram uma fauna de moluscos mais rica, abundante e diversa. Especificamente no caso dos moluscos, a composição de espécies foi tipicamente marinha, cuja riqueza pode ser considerada alta com relação a outros ambientes de manguezal. Além disso, a malacofauna foi composta predominantemente por micromoluscos, cujos tamanhos quando adultos não ultrapassam os 10 mm, e por indivíduos jovens de espécies que atingem um porte maior. Sugere-se que tanto a complexidade do habitat quanto a sazonalidade afetam a riqueza, diversidade e abundância das comunidades associadas. De um modo geral, as macroalgas marinhas oferecem suporte para uma diversidade de táxons marinhos, sendo habitats fundamentais para o aumento da complexidade estrutural subaquática do ecossistema manguezal.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-03-31T15:55:37Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Edivaldo Lima PPGBA_2015.pdf: 1216837 bytes, checksum: a0087d1ed1223b4689da6194020ad828 (MD5) / Made available in DSpace on 2016-03-31T15:55:37Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Edivaldo Lima PPGBA_2015.pdf: 1216837 bytes, checksum: a0087d1ed1223b4689da6194020ad828 (MD5) Previous issue date: 2014-08-28 / FACEPE / O pisoteio decorrente do tráfego de pedestres sobre os recifes de coral é um fenômeno associado ao turismo em muitas praias de Pernambuco. No ambiente fital o pisoteio pode afetar as algas e a fauna associada, modificando a estrutura das comunidades. O filo Tardigrada é componente permanente da meiofauna sendo encontrado no sedimento marinho e associado a macroalgas. O presente trabalho teve como objetivo avaliar o efeito do pisoteio sobre os tardígrados associados ao fital dos recifes de Porto de Galinhas, PE. Para isso delineou-se experimentos observacionais e manipulativos com intuito de avaliar o impacto do turismo e das simulações de pisoteio humano sobre a comunidade de Tardigrada. No primeiro experimento foram determinadas estações pareadas ao longo dos recifes, seguindo os limites entre a área protegida e a exposta ao trafego humano, avaliando se a comunidade diferia em consequência do pisoteio. Os tardígrados apresentaram abundâncias aparentemente condicionadas pelo tipo de substrato, mostrando reduções na densidade quando associados a Gelidiela acerosa, e exibindo maior densidade na área impactada quando associados Chodrophicus papillosus. Para o segundo experimento foram determinados transects na área protegida do recife e executados dois níveis de intensidade de pisoteio sobre o substrato recifal. A avaliação do efeito do pisoteio seguiu um desenho experimental BACI (Antes/Depois e Controle/Impacto), sendo as amostras coletadas para monitoramento do nível de recuperação da comunidade com um, dois e três meses após cessado o pisoteio. Como resultado deste trabalho, houve redução das variáveis do substrato algal (biomassa, cobertura, peso do substrato e altura do tapete) e também na densidade de Tardigrada, com valores seguindo uma tendência de redução tanto maior o nível de estresse. Variações locais, foram determinantes para a estrutura da comunidade de Tardigrada, dificultando a compreensão dos efeitos do impacto. O processo de recuperação foi independente da intensidade do distúrbio, alcançando valores estabilizados já no primeiro mês. / The trampling resulting from pedestrian traffic on coral reefs is a phenomenon associated with tourism in many beaches of Pernambuco. In phytal environment the trampling can affect the algae and associated fauna, modifying the structure of communities. The phylum Tardigrada is permanent component of the meiofauna being found in marine sediment and associated with macroalgae. This study aimed to evaluate the effect of trampling on tardigrades associated with the phytal of reefs of Porto de Galinhas, PE. For this were outlined observational and manipulative experiments in order to assess the impact of tourism and simulations of human trampling on the community of tardigrades. In the first experiment were paired certain stations along the reefs, following the boundaries of the protected area and exposed to human traffic, assessing whether the community differed as a result of trampling. The tardigrades presented abundances apparently conditioned by the type of substrate, showing reductions in density when associated with a Gelidiela acerosa, and exhibiting higher density in the impacted area when associated Chodrophicus papillosus. For the second experiment were determined transects in protected reef area and run two levels of intensity of trampling on reef substrate. The evaluation of the effect of trampling followed a experimental design BACI (Before / After and Control / Impact), being the samples collected for monitoring of the level of recovery of the community with one, two and three months after trampling ceased. As a result of this work, there was a reduction of the algal substrate variables (biomass, cover, substrate weight and turf height) and also the density of tardigrades, with values following a trend of greater reduction in both the level of stress. Local variations were crucial to the structure of the tardigrades community, making the understanding of the effects of the impact difficult. The recovery process was independent of the intensity of the disturbance, reaching values stabilized in the first month.

Orientadora: Profa. Dra. Ana Maria Pereira Neto / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Energia, 2014. / Este trabalho avaliou o potencial energético da biomassa de Chlorella minutissima cultivada em condição autotrófica em meio Guillard f/2 e mixotrófica com o mesmo meio e adição de glicose em diferentes condições: I) adição fracionada de 0,2 g/L de glicose com um intervalo de 48h para atingir a adição total de 0,4 g/L; II) adição de 0,2 g/L de glicose em única dose no início do cultivo; III) adição de 0,2 g/L de glicose em única dose após 72h do início do cultivo e IV) adição fracionada de 0,05 g/L de glicose, após 72h de cultivo, seguida de três adições em intervalos de 48h, até atingir a adição total de 0,2 g/L. As curvas de crescimento dos cultivos foram determinadas a partir do monitoramento diário da densidade celular. A produtividade e os teores de carboidratos, clorofila-a, carotenoides, poder calorífico superior e análises elementar e imediata da biomassa foram determinados. E os teores de proteínas, lipídios e poder calorífico inferior foram estimados para o último dia dos cultivos. Observou-se que a adição de glicose após 72h do início do cultivo, em dose única ou fracionada, melhorou o aproveitamento desta fonte de carbono pelas microalgas, minimizando o consumo pelas bactérias uma vez que os cultivos foram xênicos. Nos cultivos mixotróficos, o teor de carboidratos foi igual ao do grupo controle (cultivos autotróficos), aproximadamente 37%, ao passo que houve aumento do teor lipídico (1,41 vezes para adição única e 1,67 vezes para a adição fracionada), indicando o potencial de aplicação de Chlorella minutissima tanto para a produção de etanol como de biodiesel. Considerando o etanol de primeira geração cuja produtividade de etanol de biomassa algácea poderia alcançar uma produtividade de dez vezes maior que a da cana-de-açúcar, e para o de segunda geração poderia chegar a quarenta vezes superior ao do bagaço de cana com base em projeções de produção anual biomassa algácea seca em torno de 90 t/ha, e considerando o mesmo teor fermentescível para as biomassa. A biomassa algácea também apresentou elevado teor de carbono (~40%) e de compostos voláteis (acima de 76% nos cultivos mixotróficos). O poder calorífico superior em condições mixotróficas chegou a 22,27 MJ/kg (maior que o da madeira, que é de cerca de 18 MJ/kg), além de um menor teor de cinzas (2,78 vezes). Estas características são positivas para aplicação da biomassa em processos de conversão termoquímica, como combustão direta e gaseificação. Além disso, os cultivos mixotróficos apresentaram uma diminuição de 0,76 vezes do teor de proteínas, o que favorece uma menor emissão de NOx nos processos termoquímicos. Os teores de clorofila e carotenoides do cultivo mixotrófico com adição única apresentaram um aumento em relação ao controle de, respectivamente, 1,79 e 1,69 mostrando um potencial para a produção de suplementos destinados à alimentação humana, viabilizando, em termos de custos, a produção de biocombustíveis a partir do uso dos carboidratos e lipídios da biomassa residual após a extração destes compostos de maior valor agregado. / This study evaluated the energetic potential of Chlorella minutissima cultivated in autotrophic (Guillard f/2 media) and mixotrophic conditions using the same medium plus glucose additions in different strategies: I) Two additions of 0.2 g/L glucose in a 48h interval up to 0.4 g/L glucose supply; II) Single addition of 0.2 g/L glucose at the beginning of the cultivation; III) Single addition of 0.2 g/L glucose after 72h from the cultivation beginning; IV) addition of 0.05 g/L glucose, 72h after the cultivation start, followed by three additions in 48h intervals up to the total supply of 0.2 g/L. Growth curves were determined by daily cell density monitoring in each cultivation flask. Productivity and carbohydrate, chlorophyll-a, carotenoids, yields and higher and ultimate and proximate analyses were done in the biomass. Were estimated lipids, protein and low heating value obtained at the end of cultivation. Glucose addition after 72h cultivation, whether in single or fractionated doses, improved the utilization of this carbon source by the microalgae, minimizing the bacterial competition once the cultures were xenic. In these treatments, the carbohydrate yield was the same as the control group (autotrophic), around 37%, whereas the lipid yields were higher (1.41 times to single addition and 1.67 times for fractionated addition) representing 31% of the bulk biomass, indicating the potential use of this Chlorella minutissima both for ethanol and biodiesel production. Considering the first generation ethanol whose productivity microalgae ethanol could achieve productivity ten times that of sugarcane, and the second generation is approximately forty times sugarcane bagasse based on projections of annual production of dry algal biomass around 90 t/ha and considering same fermentable yield of the biomass. The algal biomass presented high carbon content (~ 40%), high volatile content (above the 76% in the mixotrophic treatments), and the higher heating value reached 22.27 MJ/kg in mixotrophic conditons, value bigger than the observed for the wood (18.25 MJ/ kg), with low ash content (2.78 times). Such characteristics are positive and indicate a good potential of this biomass be applied in thermochemical processes, such as combustion and gasification. Also the decrease of 0.76 times of protein content in the mixotrophic cultures allows lower NOx emission in thermochemical processes. Chlorophyll and carotenoids yields in the cultures with single glucose addition were respectively 1.78 e 1.69 higher than the in autrotrophic ones, also indicating the potential use of these coproducts for food supply for human consumption allowing, in terms of costs, the production of biofuels from the use of carbohydrates and lipids from the residual biomass after the removal of these high value-added compounds.

Made available in DSpace on 2015-09-25T12:22:18Z (GMT). No. of bitstreams: 1 PDF - Rafaela Cristina de Souza Duarte.pdf: 17178678 bytes, checksum: bd68b4b71283d326a8bc5494f62f32d1 (MD5) Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Mangroves have a mosaic of different habitats and microhabitats, each with their specific levels of complexity and occupied by different kinds of organisms. In this context, the present study aimed to assess the effect of habitat complexity and seasonality in the composition and structure of the invertebrate macrofauna associated with macroalgal species with different morphological characteristics. The research was conducted in the hypersaline mangrove of Tubarão River (5 o 04'34.87"S, 36 o 27'32.36"W), municipality of Macau, northern coast of the state of Rio Grande do Norte, Northeastern Brazil. Aiming to analyze the effect of habitat complexity on a local microhabitat scale and considering that the studied mangrove, due to their peculiar hipersalinity characteristics may harbor a rich fauna and flora, the following questions guide this research: a) Does the different macroalgae studied have different degree of habitat complexity? b) Macroalgae with different morphological characteristics supports invertebrate communities significantly different? c) Is there a relationship between habitat complexity and the composition, abundance and diversity of the invertebrate community of their phytal? and d) Is there difference between the pattern of abundance and composition of invertebrates found in macroalgal species between the dry and rainy seasons? A total of 1,750 individuals classified into five taxa were collected: Echinodermata, Amphipoda, Mollusca, Isopoda and Polychaeta, with 723 individuals found in the rainy season (associated with Gracilaria sp.) and 1,028 in the dry season (430 in Dictyota sp. and 598 in Solieria filiformes). Macroalgae of the dry period were morphologically distinct, however, the invertebrate fauna were not significantly different (p=0.1037), thus reinforcing that seasonality may have influenced the abundance and composition of macroinvertebrate taxa. The different macroalgae showed distinct morphological patterns and different degrees of habitat complexity, where more complex algae harbored a richer, abundant and diverse mollusc fauna. Specifically in the case of molluscs, species composition was typically marine, higher than other mangrove environments. Furthermore, the malacofauna was predominantly composed by micromolluscs, as adults whose sizes do not exceed 10 mm, and young individuals of species that reach a larger size. It is suggested that both habitat complexity as well as seasonality affect the richness, diversity and abundance of associated communities. In general, the marine macroalgae provides support for a variety of marine taxa, and may play an important role in increasing the structural underwater habitat complexity of mangrove systems. / Os manguezais apresentam um mosaico composto por diversos habitats e microhabitats, cada um deles com seus níveis de complexidade específicos e ocupados por diferentes tipos de organismos. Nesse contexto, o presente estudo tem por objetivo avaliar o efeito da complexidade do habitat e da sazonalidade na composição e estrutura da macrofauna associada a diferentes espécies de macroalgas com características morfológicas distintas. A pesquisa foi desenvolvida no manguezal hipersalino do Rio Tubarão (5º04 34,87 S; 36º27 32,36 O), município de Macau, litoral setentrional do estado do Rio Grande do Norte, Nordeste do Brasil. No intuito de analisar o efeito da complexidade do habitat em uma escala local de microhabitat e considerando que o manguezal estudado, devido à suas características peculiares de hipersalinidade podem abrigar uma rica fauna e flora, as seguintes perguntas nortearam esta pesquisa: a) As diferentes espécies de algas apresentam graus de complexidade de habitat distintos? b) Algas com características morfológicas diferenciadas suportam comunidades de invertebrados significativamente diferentes? c) Existe uma relação entre a complexidade do habitat oferecido pelas macroalgas e a composição, abundância, riqueza e diversidade de invertebrados participantes de seu fital? d) Existem diferenças entre o padrão de abundância e composição de invertebrados encontrados nas espécies de macroalgas entre os períodos seco e chuvoso? Foram coletados 1.750 indivíduos classificados em cinco taxa: Echinodermata, Amphipoda, Mollusca, Isopoda e Polychaeta, sendo 723 indivíduos encontrados no período chuvoso (associados à Gracilaria sp.) e 1.028 no período seco (430 em Dictyota sp. e 598 em S. filiformes). macroalgas apesar de serem morfologicamente distintas não apresentaram uma fauna de invertebrados significativamente diferente (p=0,1037), reforçando assim, que a sazonalidade pode ter influenciado a abundância e composição dos táxons de macroinvertebrados. As diferentes macroalgas apresentaram padrões morfológicos distintos e diferentes graus de complexidade de habitat, onde algas mais complexas abrigaram uma fauna de moluscos mais rica, abundante e diversa. Especificamente no caso dos moluscos, a composição de espécies foi tipicamente marinha, cuja riqueza pode ser considerada alta com relação a outros ambientes de manguezal. Além disso, a malacofauna foi composta predominantemente por micromoluscos, cujos tamanhos quando adultos não ultrapassam os 10 mm, e por indivíduos jovens de espécies que atingem um porte maior. Sugere-se que tanto a complexidade do habitat quanto a sazonalidade afetam a riqueza, diversidade e abundância das comunidades associadas. De um modo geral, as macroalgas marinhas oferecem suporte para uma diversidade de táxons marinhos, sendo habitats fundamentais para o aumento da complexidade estrutural subaquática do ecossistema manguezal.

Made available in DSpace on 2015-09-25T12:22:19Z (GMT). No. of bitstreams: 1 PDF - Rafaela Cristina de Souza Duarte.pdf: 17178678 bytes, checksum: bd68b4b71283d326a8bc5494f62f32d1 (MD5) Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Mangroves have a mosaic of different habitats and microhabitats, each with their specific levels of complexity and occupied by different kinds of organisms. In this context, the present study aimed to assess the effect of habitat complexity and seasonality in the composition and structure of the invertebrate macrofauna associated with macroalgal species with different morphological characteristics. The research was conducted in the hypersaline mangrove of Tubarão River (5 o 04'34.87"S, 36 o 27'32.36"W), municipality of Macau, northern coast of the state of Rio Grande do Norte, Northeastern Brazil. Aiming to analyze the effect of habitat complexity on a local microhabitat scale and considering that the studied mangrove, due to their peculiar hipersalinity characteristics may harbor a rich fauna and flora, the following questions guide this research: a) Does the different macroalgae studied have different degree of habitat complexity? b) Macroalgae with different morphological characteristics supports invertebrate communities significantly different? c) Is there a relationship between habitat complexity and the composition, abundance and diversity of the invertebrate community of their phytal? and d) Is there difference between the pattern of abundance and composition of invertebrates found in macroalgal species between the dry and rainy seasons? A total of 1,750 individuals classified into five taxa were collected: Echinodermata, Amphipoda, Mollusca, Isopoda and Polychaeta, with 723 individuals found in the rainy season (associated with Gracilaria sp.) and 1,028 in the dry season (430 in Dictyota sp. and 598 in Solieria filiformes). Macroalgae of the dry period were morphologically distinct, however, the invertebrate fauna were not significantly different (p=0.1037), thus reinforcing that seasonality may have influenced the abundance and composition of macroinvertebrate taxa. The different macroalgae showed distinct morphological patterns and different degrees of habitat complexity, where more complex algae harbored a richer, abundant and diverse mollusc fauna. Specifically in the case of molluscs, species composition was typically marine, higher than other mangrove environments. Furthermore, the malacofauna was predominantly composed by micromolluscs, as adults whose sizes do not exceed 10 mm, and young individuals of species that reach a larger size. It is suggested that both habitat complexity as well as seasonality affect the richness, diversity and abundance of associated communities. In general, the marine macroalgae provides support for a variety of marine taxa, and may play an important role in increasing the structural underwater habitat complexity of mangrove systems. / Os manguezais apresentam um mosaico composto por diversos habitats e microhabitats, cada um deles com seus níveis de complexidade específicos e ocupados por diferentes tipos de organismos. Nesse contexto, o presente estudo tem por objetivo avaliar o efeito da complexidade do habitat e da sazonalidade na composição e estrutura da macrofauna associada a diferentes espécies de macroalgas com características morfológicas distintas. A pesquisa foi desenvolvida no manguezal hipersalino do Rio Tubarão (5º04 34,87 S; 36º27 32,36 O), município de Macau, litoral setentrional do estado do Rio Grande do Norte, Nordeste do Brasil. No intuito de analisar o efeito da complexidade do habitat em uma escala local de microhabitat e considerando que o manguezal estudado, devido à suas características peculiares de hipersalinidade podem abrigar uma rica fauna e flora, as seguintes perguntas nortearam esta pesquisa: a) As diferentes espécies de algas apresentam graus de complexidade de habitat distintos? b) Algas com características morfológicas diferenciadas suportam comunidades de invertebrados significativamente diferentes? c) Existe uma relação entre a complexidade do habitat oferecido pelas macroalgas e a composição, abundância, riqueza e diversidade de invertebrados participantes de seu fital? d) Existem diferenças entre o padrão de abundância e composição de invertebrados encontrados nas espécies de macroalgas entre os períodos seco e chuvoso? Foram coletados 1.750 indivíduos classificados em cinco taxa: Echinodermata, Amphipoda, Mollusca, Isopoda e Polychaeta, sendo 723 indivíduos encontrados no período chuvoso (associados à Gracilaria sp.) e 1.028 no período seco (430 em Dictyota sp. e 598 em S. filiformes). macroalgas apesar de serem morfologicamente distintas não apresentaram uma fauna de invertebrados significativamente diferente (p=0,1037), reforçando assim, que a sazonalidade pode ter influenciado a abundância e composição dos táxons de macroinvertebrados. As diferentes macroalgas apresentaram padrões morfológicos distintos e diferentes graus de complexidade de habitat, onde algas mais complexas abrigaram uma fauna de moluscos mais rica, abundante e diversa. Especificamente no caso dos moluscos, a composição de espécies foi tipicamente marinha, cuja riqueza pode ser considerada alta com relação a outros ambientes de manguezal. Além disso, a malacofauna foi composta predominantemente por micromoluscos, cujos tamanhos quando adultos não ultrapassam os 10 mm, e por indivíduos jovens de espécies que atingem um porte maior. Sugere-se que tanto a complexidade do habitat quanto a sazonalidade afetam a riqueza, diversidade e abundância das comunidades associadas. De um modo geral, as macroalgas marinhas oferecem suporte para uma diversidade de táxons marinhos, sendo habitats fundamentais para o aumento da complexidade estrutural subaquática do ecossistema manguezal.

During the summer of 2013 the environmental office at Lycksele Municipality received a complaint, regarding algal blooms at the stream outlet between the lakes Kalven and Byssträsket in the southern parts of Lycksele Municipality. No deeper studies were made to ensure what could have caused the bloom. The purpose of this report was to examine if there was a specific source contributing to high levels of nutrients in the stream, mainly focusing on clear-cuts and a small dam by the stream inlet, and if the nutrient status differed along the stream flow. Therefore, suitable sites were picked for examination, following the stream flow between the two lakes, and in a stream not affected by clear-cuts for reference. Water samples were picked at each site, determining the status of the parameters total-nitrogen, total-phosphorus, nitrate, ammonium, pH and conductivity. The result showed quite high levels of total-phosphorus (ranging from 40-50 µg/l) and total-nitrogen (ranging from 350-450 µg/l), but low levels of ammonium and nitrate. The results showed no sign of a nutrient input from a specific location. The conclusion of this study is that the present nutrient levels could be high enough to result in a bloom, though probably dependent on contributing factors, such as warmer weather and lower water levels. An alternative explanation is that the nutrient levels could have been higher 2013, deriving from new clear-cuts, but that these clear-cuts stopped leaching nutrients due to older age. Hence, due to lack of previous studies no exact assumption can be made

Climate change is arguably the greatest environmental and economic challenge of our time. There are considerable documented and projected impacts to both human and natural systems as a result of climate change. These impacts include changes in temperature, sea level, precipitation patterns, and biogeography of ecologically and economically relevant species, including pathogens. One of the main drivers of climate change is elevated levels of atmospheric carbon dioxide (CO2), a greenhouse gas. Since pre-industrial times, atmospheric CO2 levels have increased from approximately 280 ppm to over 400 ppm, as a result of fossil fuel combustion, cement production and land use change. In addition to being a driver of climate change and a direct contributor to the increase in global average temperatures, elevated atmospheric CO2 also affects biogeochemical cycles. When ocean surface waters equilibrate with higher levels of atmospheric CO2, there is an increase in acidification and resulting effects on marine biota, such as changes to community composition and decreases in calcifying organisms. Freshwater systems are less understood, but many freshwater systems are experiencing acidification and the resulting ramifications as well. Microalgae, as the primary producers in these systems, are often studied as sentinels of such change. Here, I present studies using microalgae to monitor and mitigate elevated CO2. The goals of the investigation were to conduct 1) a field study to determine if microalgae in a freshwater stream were impacted by an elevated CO2 treatment; 2) a meta-analysis of elevated CO2 effects on freshwater microalgae; and 3) a laboratory study to optimize growth of microalgae for biofuels production. In the first chapter, I provide background information and the framework for the studies that follow. Past, present and future atmospheric carbon dioxide levels are discussed as well as their impacts to marine and freshwater systems. The importance of microalgae to these aquatic systems is described. Then I discuss the role of microalgae in elevated CO2 monitoring and mitigation. In the second chapter, I present a field study of elevated CO2 effects on a freshwater stream. The study took place at the University of Michigan Biological Station at the Stream Research Facility. Once-through artificial stream channels were employed to grow microalgae in simulated natural stream conditions. The stream channels were subjected to ambient or elevated CO2 treatments and impacts to stream water chemistry and microalgae were measured. Stream water chemistry was impacted by the elevated CO2 treatment such that there were significant decreases in pH and significant increases in dissolved inorganic carbon. However, these chemical changes did not have a measured impact on the stream microalgae, as measured by microalgal biomass, elemental composition, and community composition. Perhaps microalgae will not be the first to be impacted by increasing levels of atmospheric CO2, though freshwater systems vary considerably and more research is needed to confirm this conclusion. In the third chapter, I present the results of a meta-analysis of elevated CO2 effects on freshwater algae. We conducted a literature search in ISI Web of Science of all publications on freshwater microalgal response to elevated CO2 and chose studies that used elevated CO2 levels of less than or equal to 2,000 ppm, which is the highest level projected for the future by the Intergovernmental Panel on Climate Change. From the twenty-two papers that met the inclusion criteria, qualitative and quantitative data were extracted and categorized into response classes including water chemistry, microalgal growth, carbon fixation and photosynthesis, nutrient uptake, and consumer response. Effect sizes for elevated CO2 were calculated, and CO2 enrichment significantly increased water acidity and dissolved inorganic carbon concentrations, microalgal growth, carbon fixation and photosynthesis, and algal nutrient uptake. Algal consumers (e.g., herbivores) in general were negatively affected, but the overall result was not statistically significant. We also analyzed a variety of experimental parameters and determined that experimental design and algal culture conditions did not impact elevated CO2 effects on freshwater microalgae in the studies conducted to date. In the fourth chapter, I provide the results of a laboratory-based study of the marine microalgae Picochlorum oculatum, which has shown promise as a source of biofuel because of its high lipid production and relative ease of growing in culture. We ran a series of lab experiments to optimize growth conditions and maximize growth of P. oculatum. Experiments included tests of light source (LED or metal halide), CO2 delivery (continuously or in pH-controlled pulses), inoculum size (10%, 15% or 20%), and culture pH (7.0, 7.5, or 8.0); these variations did not significantly impact growth so future experiments were run in the most cost-effective manner using LED lights, with pH-controlled pulses, 10% inoculum size and at culture pH of 7.5. We also tested different sources of supplied nitrogen in an effort to reduce culture costs and potentially improve sustainability by using urea and ammonium, sources of nitrogen readily available from wastewater treatment. Growth was comparable using the standard artificial nitrogen source, nitrate, and the wastewater-constituent urea, indicating that urea may be a cost-effective and sustainable source of nitrogen for microalgal cultures grown on an industrial scale for biofuel production. Growth using ammonium was not successful even when concentrations were reduced and a buffer was added to reduce acidification of the growth medium resulting from ammonium uptake by the algae. More research is needed to determine if ammonium can be a suitable nitrogen source for microalgae. Experiments were also conducted in an outdoor setting to determine if high growth levels were maintained when the cultures were grown at a larger scale and in variable natural conditions; successful growth was demonstrated over 68 days, indicating that P. oculatum may be a promising candidate for biofuel production. Additional research is needed to further optimize culture growth and streamline operations. The body of work herein examines the role of microalgae in elevated CO2 monitoring and mitigation. There is considerable evidence that elevated atmospheric CO2 impacts aquatic chemistry through increases in dissolved inorganic carbon and acidity. These chemical changes have varied impacts on aquatic biota, including microalgae, which play foundational roles in ecosystems as primary producers and bases of food webs. Microalgal responses to elevated CO2 may impact other trophic levels and have widespread effects on aquatic ecosystems. Additional research is needed on elevated CO2 effects on microalgae, particularly in freshwater systems, which are less understood than marine systems and perhaps less predictable due to the wide variability in their physical, chemical and biological compositions. Microalgae may also play a significant role in elevated CO2 mitigation because of their potential in biofuel production. With additional research focused on reducing costs and improving sustainability, microalgae may play an important role in reducing elevated CO2, one of the main drivers of climate change.

The purposes of this study were to characterize the complexation of toxic metals with algal toxins and to determine the effects of arsenic and copper on the growth of Karenia brevis under specific experimental conditions. Microcystins, pahayokolides, brevetoxins and okadaic acid were used as representatives of algal toxins while arsenic, copper, cadmium, cobalt, iron, manganese and mercury were selected as typical toxic metals (including metalloids here) in the aquatic environment. The stabilities of the toxin-metal complexes were determined using equilibrium dialysis and/or centrifugal ultrafiltration technique. A direct exposure of arsenic and copper to the K. brevis was carried out to determine the effects of these metals to the growth of the algal cell. The results indicated that Cu2+, Hg2+, Co2+, Cd2+ and Fe2+ were capable of complexing with the algal toxins. Moreover, the exposure experiments demonstrated that the high concentration of arsenic and copper could affect the growth of the K. brevis.

Algae are important to marine and fresh-water ecosystems. However, some species of algae are harmful or even toxic. They can consume oxygen or block sunlight that is essential for other organisms to live. Indeed, some algae blooms can produce toxins that damage the health of the environment, plants, animals, and humans. Harmful algal blooms (HABs) which are often more green, brown, or dark-colored than red have spread along the coastlines and in the surface waters of the United States. Therefore, scientists are making great efforts to study HABs in order to maintain human and ecosystem health. Karenia brevis, the major harmful algal bloom dinoflagellate of the Gulf of Mexico, plays a destructive role in the region. Karenia brevis, responsible for Florida red tide, is the principle HAB dinoflagellate in the Gulf of Mexico. K. brevis blooms can produce brevetoxin: ladder-shaped polyether (LSP) compounds, which can lead to adverse human health effects, like reduced respiratory function through inhalation exposure, or neurotoxic shellfish poisoning through consumption of contaminated shellfish. The poisoning has been attributed to their affinity for voltage-sensitive sodium ion channels causing channel opening and depolarization of excitable cell membranes. Conservative estimate suggests that the economic impact from all harmful algal bloom events in the United States is at least $82 million/year. The public health costs occupy $37 million alone. The study presented herein utilized fluorescent and photolabile brevetoxin probes to demonstrate that brevetoxin localizes in the chloroplast of K. brevis where it binds to light harvest complex II (LHC II) and thioredoxin (Trx). It had been discovered that the TrxR/Trx system was inhibited by brevetoxin-2 (PbTx-2) with an IC50 of 25 µM. The mechanism of the inhibition was discussed in this work. The research also revealed that the K. brevis high-toxic and low-toxic strains have a significant difference in their ability, not only to produce brevetoxin, but also to perform NPQ and in the production of ROS. I compared and contrasted various metabolic and biochemical parameters in two strains of K. brevis which had a ten-fold difference in toxin content. The work could shed light on the physiological role that brevetoxin fills for K. brevis and may contribute to understanding the effect of ladder-shaped polyether compounds on both marine animals and exposed humans and shall inform improved treatments for brevetoxicosis.