Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / No semi-Ãrido brasileiro, devido Ãs caracterÃsticas climÃticas, ao regime irregular de chuvas e Ãs caracterÃsticas do solo, a principal fonte de Ãgua para abastecimento humano tem sido os reservatÃrios artificiais de superfÃcie, aÃudes. A ocupaÃÃo e exploraÃÃo desordenada dos recursos naturais nas bacias hidrogrÃficas, alÃm da alta evaporaÃÃo e da radiaÃÃo solar, interferem negativamente na qualidade da Ãgua armazenada. Como consequÃncia, esses reservatÃrios apresentam um processo de eutrofizaÃÃo acelerado, levando frequentemente a floraÃÃes de fitoplÃnctons, comunidade esta predominantemente dominada por CianobactÃrias. Devido grande parte desses organismos serem produtores de toxinas, podendo causar uma sÃrie de problemas à populaÃÃo, decidiu-se monitorar a comunidade fitoplanctÃnica do aÃude SÃtios Novos, reservatÃrio de usos mÃltiplos, localizado no municÃpio de Caucaia-CE, de janeiro de 2010 a junho de 2011 investigando a produÃÃo de toxinas pelos organismos dominantes. Identificou-se 41 tÃxons, 19 de cianobactÃrias e 22 de algas. Apesar da predominÃncia de nÃmero de tÃxons de algas, estas representaram menos de 10% dos organismos quantificados, com exceÃÃo de 1 amostragem. Jà as cianobactÃrias estiveram presentes em todas as amostragens, dominando quantitativamente o ambiente aquÃtico. Dentre o grupo de cianobactÃrias, destacaram-se Planktothrix agardhii (PA) e Cylindrospermosis raciborskii (CR). A abundÃncia de PA ao longo de todo o perÃodo de amostragem variou de 0 a 5.83x105 cel.mL-1, o que representou 94% da abundÃncia total do fitoplÃncton. A densidade mÃdia da PA foi 7.54.104 cel.mL-1. A abundÃncia CR no mesmo perÃodo variou de 0 a 3.32x104 cell.mL-1, representando 18,9% do total da comunidade fitoplanctÃnica. A abundÃncia mÃdia de CR foi 8.21.103 cel.mL-1. As espÃcies dominantes foram isoladas, e realizando-se bioensaios em camundongos, teste ELISA e mÃtodo de detecÃÃo por HPLC, observou-se a produÃÃo de STX e dc-STX pela CR e dc-GTX pela PA. Essa problemÃtica evidencia a necessidade da implementaÃÃo de aÃÃes integradas dos ÃrgÃos ambiental, de gestÃo dos recursos hÃdricos e companhia de sanamento estadual visando a prevenÃÃo e remediaÃÃo do processo de degradaÃÃo da qualidade da Ãgua, atuando na ampliaÃÃo do saneamento bÃsico, na educaÃÃo ambiental, na fiscalizaÃÃo dos usos e ocupaÃÃes do solo na bacia hidrogrÃfica mas, principalmente, no controle das atividades de piscicultura na bacia hidrÃulica, que ocorrem de maneira superintensiva. / In Brazilian semi-arid Northeast region due to irregular rainfall regime, climatic and soil characteristics, the main source of human water supply has been artificial surface reservoirs. Disorderly occupation and exploitation of natural resources on those hydrographic basins, alongside high evaporation and solar radiation, promote negative impact on stored water quality. As a consequence, the reservoirs present themselves in a process of accelerated eutrophication, often leading to phytoplankton blooms, predominantly dominated by Cyanobacteria. Due to many of these organisms are toxin-producing, which can cause a sort of problems to the population, it was decided to monitor the phytoplankton community of a multipurpose reservoir, located in the municipality of Caucaia-CE, from January 2010 to June 2011, as well as investigate the production of toxins by the dominant organisms. We identified 41 taxa, 19 of cyanobacteria and 22 of algae. Despite the predominance of algae over the identified taxa, they accounted for less than 10% of the quantified organisms, except for one sample. However cyanobacteria were present in all samples, quantitatively dominating the aquatic environment. Among the group of cyanobacteria, excelled Planktothrix agardhii (PA) and Cylindrospermosis raciborskii (CR). PA abundance along all sampling period ranged from 0 to 5.83x105 cells.mL-1 , which accounted for 94% of the total phytoplankton abundance. The average density of PA was 7.54.104 cells.mL-1 . The CR abundance in the same period ranged from 0 to 3.32x104 cells.mL-1 , accounting for 18,9% of total phytoplankton community. The average abundance of CR was 8.21.103 cells.mL-1. The dominant species were isolated and carrying out mice bioassay , ELISA and HPLC analysis, we observed the production of STX and dc-STX by CR and dc-GTX by PA. This issue highlights the need for the implementation of integrated actions from environmental agencies, water resources management and sanitation State companies towards the prevention and remediation of the degradation of water quality, acting in the expansion of sanitation, environmental education, oversighting of the use and occupation of the watershed lands, but mainly in the control of aquaculture activities in the hydraulic basin, which occur in a super intensive way.

Para suprir a carÃncia hÃdrica, o Cearà dispÃe de uma grande rede de reservatÃrios artificiais destinados aos mais diversos usos. PorÃm, Ãguas que permanecem reservadas em aÃudes sÃo limnolÃgicamente vulnerÃveis, sendo o fenÃmeno da eutrofizaÃÃo uma das piores consequÃncias resultantes das atividades antrÃpicas desenvolvidas nas Ãreas de contribuiÃÃo desses reservatÃrios, consequÃncias essas que sÃo agravadas ainda mais em funÃÃo das caracterÃsticas naturais do semiÃrido, um ambiente marcado por baixas precipitaÃÃes pluviomÃtricas e pela sua mà distribuiÃÃo no espaÃo e no tempo. Para auxiliar no estudo trÃfico dessas Ãguas, hà muito vem sendo utilizada pelos limnÃlogos uma ferramenta destinada a classificar os recursos hÃdricos no tocante ao seu estado de trofia, o IET - Ãndice do Estado TrÃfico, desenvolvido por Carlson (1977). A pesquisa aqui desenvolvida consistiu em aprimorar o estudo da correlaÃÃo entre os parÃmetros de Clorofila a, fÃsforo total e TransparÃncia de Secchi, utilizados na composiÃÃo do IET, bem como ajustar a escala logaritmica do Ãndice, basaeando-se nas medidas mÃnimas e mÃximas de Secchi para os reservatÃrios de Ãgua do CearÃ, o que resultou em uma metodologia de classificaÃÃo trÃfica adaptada Ãs condiÃÃes dos sistemas lÃnticos inseridos no semiÃrido cearense. / To meet the water shortage, Cearà has an extensive network of artificial reservoirs intended for various uses. However, waters that remain reserved in dams present limnological vulnerability, and the phenomenon of eutrophication is one of the worst consequences of anthropic activities developed in the areas of contribution of these reservoirs, consequences that are aggravated due to the natural characteristics of semiarid, an environment marked by low rainfall and its poor distribution in space and time. To assist the trophic study of these waters, it has long been used by limnologists a tool to classify water resources in relation to their trophic state, the TSI - the Trophic State Index, developed by Carlson (1977). The research conducted here was to enhance the study of the correlation among the parameters of chlorophyll a, total phosphorus, and Secchi Transparency, used in the composition of the TSI, as well as to adjust the logarithmic scale of the index, according to Secchi's maximum and mi nimum measures to the water reservoirs of CearÃ, which resulted in a trophic classification methodology adapted to the conditions of the inserted lentic systems in Cearà semiarid

The water quality from a reservoir is subject to all natural and anthropogenic factors acting in its watershed . The state of Cearà since the late 80s has adopted a policy of construction of water reservation to fulfill the so-called hydric emptiness. It has been observed that the waters of these new lakes, as well as the previously constructed , is experiencing a process of deterioration, mainly caused by eutrophication. The eutrophication causes a series of changes in the water system, the most relevant being the cyanobacteria blooms. Some of these organisms may be capable of producing toxins, termed cianotoxins , which are able of causing diseases and, in extreme cases, humans and animals death. This work was performed at the Acarape do Meio reservoir, located in the municipality of RedenÃÃo - CearÃ. Phytoplankton community data, with emphasis on cyanobacteria, was analyzed during the period of May 2012 to May 2013. 49 taxa distributed into 07 classes , Cyanobacteria representing 40 %, were identified. Despite the elevated number of taxa of algae, total quantity of these organisms ranged from 2.16 % (May/2012 ) to 0.34 % ( June/2012 ) while cyanobacteria were present in all samples, ranging between 97.84 % ( May/12 ) to 99.66% ( junho/12 ), quantitatively dominating the aquatic environment . The dominant species in all samples was the cyanobacterium Cylindrospermosis raciborskii, reaching an average density in April, 2012 of 1.121.328 cel.mL-1. As for the Trophic State Index, it pointed out that the reservoir was eutrophic . When the density of cyanobacteria was correlated with rainy periods and macronutrients , it showed a strong positive correlation with seasonality but a weak correlation with nitrogen and phosphorus, probably caused by the high quantities of these macronutrients present during the study period. / A qualidade da Ãgua de um reservatÃrio està condicionada a todos os fatores naturais e antrÃpicos que agem na sua bacia hidrogrÃfica. O estado do Cearà desde o final da dÃcada de 80 adotou uma polÃtica de construÃÃo de obras de reservaÃÃo hÃdrica, voltadas a preencher os chamados vazios hÃdricos. O que se tem observado, à que as Ãguas destes aÃudes, bem como os anteriormente construÃdos, vem sofrendo um processo de deterioraÃÃo de suas Ãguas, ocasionado principalmente pelo processo de eutrofizaÃÃo, onde as aÃÃes antrÃpicas sÃo as causas principais. A eutrofizaÃÃo ocasiona uma sÃrie de mudanÃas na massa de Ãgua de um sistema hÃdrico, sendo a mais relevante o surgimento de floraÃÃo de cianobactÃrias, podendo alguns destes organismos, serem capazes de produzir toxinas, denominadas de cianotoxinas, as quais sÃo capazes de ocasionar doenÃas e, em casos extremos, o Ãbito de seres humanos e animais. Este trabalho foi realizado no aÃude Acarape do Meio, localizado no municÃpio de RedenÃÃo-CE, com o objetivo de analisar durante o perÃodo de Maio de 2012 a Maio de 2013, a comunidade fitoplanctÃnica do citado reservatÃrio com Ãnfase em cianobactÃrias. Foram identificados 49 tÃxons distribuÃdos em 07 classes, dentre as CianobactÃrias representaram 40 %. Apesar da existÃncia do bom nÃmero de tÃxons de algas, estas variaram entre 2,16% (maio/2012) e 0,34% (junho/2012) dos organismos quantificados no reservatÃrio, enquanto as cianobactÃrias estiveram presentes em todas as amostragens, variando entre 97,84% (maio/12) a 99,66% (junho/12), dominando quantitativamente o ambiente aquÃtico. A espÃcie dominante em todas as amostragens foi a cianobactÃria Cylindrospermosis raciborskii, chegando a atingir uma densidade mÃdia no mÃs de abril de 1.121.328 cÃl. mL-Â. Quanto ao IET, este apontou que o manancial estava hipereutrÃfizado. Quando a densidade de cianobactÃrias foi correlacionada aos perÃodos chuvosos e secos e aos macronutrientes (nitrogÃnio e fÃsforo), havendo uma correlaÃÃo positiva com a sazonalidade, e uma fraca correlaÃÃo com o nitrogÃnio e o fÃsforo, provavelmente, ocasionada pela a alta taxa destes macronutrientes presentes durante o perÃodo de estudo.

Com a finalidade de atender a demanda energética, muitos reservatórios foram construídos no Brasil e, notadamente na região Sudeste, as construções das barragens não somente atenderam aos usos múltiplos (geração de energia, irrigação, lazer e abastecimento público), como também foram elementos propulsores da economia regional, contribuindo para a expansão das atividades industriais e rurais, bem como, um desordenado crescimento urbano. Em conseqüência da falta de planejamento, áreas naturais foram desmatadas, sendo substituídas por formas de plantio inadequadas e por projetos de especulação imobiliária não condizentes com a sustentabilidade ambiental. No decorrer das últimas décadas, os impactos aumentaram em magnitude e extensão, ocasionando sérios problemas aos recursos hídricos, culminando em conflitos pelo uso da água. Dentro deste contexto, destaca-se o rio Tietê, o qual percorre importantes cidades e extensas áreas rurais no Estado de São Paulo, sendo que, neste longo percurso, recebe a contribuição de diversos tributários (poluídos ou não) e efluentes urbanos, industriais e aqueles derivados de fontes não pontuais, além do processo de fragmentação que foi instalado a partir da construção de inúmeras barragens. De forma conjunta, todos os fatores promoveram alterações significativas no sistema e, procurando avaliar a situação atual dos reservatórios, desenvolveu-se uma pesquisa direcionada à análise da composição, densidade e distribuição da comunidade fitoplanctônica e sua relação com as variáveis limnológicas, climatológicas e hidrodinâmicas dos reservatórios da Barra Bonita, Bariri, Ibitinga, Promissão, Nova Avanhandava, Três Irmãos, além dos rios Tietê e Piracicaba e parte do rio Paraná (reservatório de Jupiá e a Jusante do reservatório de Ilha Solteira). Para tanto, foram realizadas coletas nos meses de fevereiro, maio, julho e outubro de 2000 e os resultados obtidos demonstram uma elevada concentração de nutrientes, com redução na seqüência dos reservatórios, além da variabilidade temporal, com efeito significativo da precipitação no transporte de materiais, promovendo alterações no estado trófico de cada sistema. A disponibilidade de nutrientes, transparência da água, vazão e tempo de residência, associados aos fatores climatológicos, foram elementos importantes no estabelecimento das populações, influenciando a composição, densidade e distribuição da comunidade fitoplanctônica, a qual apresentou maior dominância das classes Cyanophyceae e Chlorophyceae, com maior contribuição em densidade e riqueza de espécies, respectivamente. / For the purpose to attend the energy requirement, many reservoirs had been constructed in Brazil, and mostly in Southeast, the barrages construction not only attended to the multiple uses (energy generation, irrigation, leisure and public supply) but were propellant elements for the regional economy, contributing to the expansion of industrial and rural activities, as well as to an disarranged urban development. In consequence of the absence of planning, natural areas had been cleared and replaced by inadequated types of plantation and by land speculation projects not suitable to the environmental sustainability. During the last decades, the impacts increased in magnitude and extension, causing serious problems to the water resources, culminating with disagreements with regards to the water utilization. In this context, Tietê River should be pointed out, since it goes through important cities and large rural areas of São Paulo State and receives, through this long route, the contribution of several tributaries (contaminated or not) and urban, industrial and other effluents, derivated from not punctual sources, besides the calving that occurred after the construction of countless barrages. Conjunctly, all the factor promoted expressive alterations in the system. Aiming to evaluate the actual reservoir situation, a research was developed, focalizing the analysis of composition, density and distribution of the planctonic community and their relationship with limnological, climatic and hydrodinamical variables from Barra Bonita, Bariri, Ibitinga, Promissão, Nova Avanhandava, and Três Irmãos reservoirs, besides Tietê and Piracicaba rivers and part of Paraná River (Jupiá Reservoir, downstream Ilha Solteira Reservoir). For this, collections had been accomplished in February, March, May, July and October 2000. The results demonstrated a high nutrient concentration, which reduces through the reservoir sequence, besides the temporal variability, with significant effect of precipitation in the material transportation, promoting alterations in the trophic condition of each system. Nutrient availability, water transparency, flow, and residence time, associated to the climatic factors, were important elements in the populations establishment, influencing composition, density and distribution of the planctonic community, which presented highest dominance of Cyanophyceae and Chlorophyceae classes, with highest density and species richness contribution, respectively.

FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / Este trabalho à uma contribuiÃÃo para o conhecimento das comunidades fitoplanctÃnicas e conseqÃentemente dos estados trÃficos de estuÃrios situados no Litoral Oeste do CearÃ, NE-Brasil: Setor I (Aracatimirim, AracatiaÃà e MundaÃ) e Setor II (Timonha, Ubatuba, RemÃdios, Coreaà e AcaraÃ); e RegiÃo Metropolitana de Fortaleza (CearÃ, Cocà e Pacoti). Amostras foram coletadas na camada sub-superficial da coluna dâÃgua, ao longo do perÃodo chuvoso (janeiro a abril/ 2005), durante marÃs enchentes e/ou vazantes. As estaÃÃes de coleta foram distribuÃdas longitudinalmente nos estuÃrios, de modo a caracterizar suas porÃÃes superiores, intermediÃrias e inferiores. A comunidade fitoplanctÃnica esteve constituÃda por 308 tÃxons distribuÃdos em seis divisÃes taxonÃmicas: Cyanophyta (66), Euglenophyta (34), Dinophyta (23), Bacillariophyta (118), Cryptophyta (6) e Chlorophyta (56), alÃm de organismos nÃo identificados (5). A composiÃÃo nas diferentes porÃÃes dos estuÃrios foi influenciada pela variaÃÃo da salinidade, havendo geralmente maior representatividade de dinoflagelados nas porÃÃes inferiores; de euglenofÃceas, cianobactÃrias, clorofÃceas e criptofÃceas nas porÃÃes superiores; e diatomÃceas em todas as porÃÃes. As grandes Ãreas do Litoral Cearense pesquisadas foram distintas quanto à composiÃÃo e densidades fitoplanctÃnicas totais. Observou-se uma grande porcentagem de tÃxons exclusivos em cada Ãrea, demonstrando que as mesmas podem apresentar diferenÃas quanto Ãs condiÃÃes abiÃticas e biÃticas, que atuam conjuntamente selecionando as espÃcies fitoplanctÃnicas que melhor se adaptarÃo. Verificou-se um gradiente crescente para a densidade total: Costa Oeste Setor II < RegiÃo Metropolitana de Fortaleza < Costa Oeste Setor I. As espÃcies que alcanÃaram maiores abundÃncias relativas na RegiÃo Metropolitana foram Phormidium sp3 e Trichodesmium erythraeum; na costa Oeste Setor I Planktolyngbya limnetica e Pseudanabaena galeata; enquanto que no Setor II Heterocapsa sp., Pseudanabaena limnetica e Nitzschia palea. As espÃcies mais freqÃentes em todo o conjunto amostral foram Cylindrotheca closterium, Nitzschia palea, Navicula sp1 e Navicula sp4. Apesar de espÃcies com preferÃncia por ambientes eutrofizados terem alcanÃado maiores densidades em estuÃrios da Costa Oeste Setor I e RegiÃo Metropolitana de Fortaleza, as mesmas tambÃm estiveram presentes nos estuÃrios da Costa Oeste Setor II, inclusive com as maiores abundÃncias relativas, pelo menos em uma das estaÃÃes. Destaca-se dentre as espÃcies com preferÃncia por condiÃÃes eutrÃficas Euglena limnophila, Ps. limnetica, Pl. limnetica, Chroococcus cf. distans e Chroococcus cf. minimus e Nitzschia palea. Isso demonstrou que todos os estuÃrios, em menor ou maior grau, estÃo sendo submetidos a impactos de natureza antrÃpica (incremento nas concentraÃÃes de nutrientes), sendo os do Litoral Oeste Setor II os que demonstraram, por ocasiÃo das amostragens, estarem com o processo de eutrofizaÃÃo em estado menos avanÃado. As altas densidades de cianobactÃrias nos estuÃrios dos Rios AracatiaÃÃ, Aracatimirim, Cearà e CocÃ, representadas inclusive por espÃcies potencialmente produtoras de toxinas (Pl. limnetica, Cylindrospermopsis raciborskii, Anabaenopsis circularis, eitlerinema amphibium e T. erythraeum), e de dinoflagelados no Pacoti, indicam a necessidade urgente de outras pesquisas e de monitoramentos para verificar a ocorrÃncia de floraÃÃes algais nocivas e tÃxicas nestes estuÃrios. O controle da emissÃo de nutrientes por atividades antrÃpicas para os mesmos tambÃm se faz urgente. / This work is a contribution to the knowledge of phytoplankton communities and hence the trophic status of estuaries located on the West Coast of Ceara, NE-Brazil: Sector I (Aracatimirim, and AracatiaÃà MundaÃ) and Section II (Timonha, Ubatuba, Remedies, and Coreaà AcaraÃ) and the Metropolitan Region of Fortaleza (CearÃ, Coco and packages). Samples were taken in sub-surface layer of the water column throughout the rainy season (January to April / 2005) for tidal flooding and / or receding. The sampling stations were distributed along the estuaries in order to characterize their upper portions, intermediate and inferior. The phytoplankton community was composed of 308 taxa belonging to six taxonomic divisions: Cyanophyta (66), Euglenophyta (34), Dinophyta (23), Bacillariophyta (118), Crytophyta (6) and Chlorophyta (56), and unidentified bodies ( 5). The composition in different parts of the estuary was influenced by variations in salinity, there is generally more representative of dinoflagellates in the lower portions; of euglenoids, cyanobacteria, chlorophytes and cryptophytes in the upper portions, and diatoms in all portions. Large areas of coastline were surveyed Squads are different in composition and total phytoplankton densities. We observed a large percentage of exclusive species in each area, showing that they may have differences in the abiotic and biotic conditions, which act jointly selecting the phytoplankton species that best adapt. There was an increasing gradient to the total density: West Coast Sector II <Fortaleza Metropolitan Area <West Coast Sector I. The species reached higher relative abundances in the metropolitan area were Phormidium sp3 and Trichodesmium erythraeum; on the west coast Sector I Planktolyngbya limnetica and Pseudanabaena galeata, while in Section II Heterocapsa sp. Pseudanabaena limnetica and Nitzschia palea. The most frequent species in the whole sample were Cylindrotheca closterium, Nitzschia palea, Navicula Navicula sp1 and SP4. Although species with a preference for eutrophic environments have reached higher densities in estuaries on the West Coast Sector I and the Metropolitan Region of Fortaleza, they were also present in the estuaries of the West Coast Sector II, even with the highest relative abundances of at least one of stations. It stands out among the species with a preference for eutrophic conditions Euglena Limnophila, Ps. limnetica, Pl limnetica, Chroococcus cf. distans and Chroococcus cf. minimus and Nitzschia palea. This demonstrated that all the estuaries, to a lesser or greater degree, are being subjected to impacts of anthropogenic nature (increase in nutrient concentration), and the West Coast Sector II, who demonstrated, on the occasion of sampling, are in the process of less advanced state of eutrophication. The high densities of cyanobacteria in estuaries of the Rivers AracatiaÃÃ, Aracatimirim, Cearà and Coco, represented by species including potentially producing toxins (Pl limnetica, Cylindrospermopsis raciborskii, Anabaenopsis circularis, Geitlerinema Amphibium and T. erythraeum), and dinoflagellates in the package, indicate the urgent need for further research and monitoring to verify the occurrence of harmful algal blooms and toxic in these estuaries. The control of nutrient emission by human activities for them also is urgent.

A presente pesquisa teve por objetivo analisar a composição e distribuição das espécies de macrófitas aquáticas no reservatório do Lobo (Broa), em quatro períodos do ano de 2007: março, maio, agosto e novembro. Para atender os objetivos propostos, variáveis limnológicas envolvendo os compartimentos água (pH, condutividade, temperatura, oxigênio dissolvido, clorofila, formas nitrogenadas e fosfatadas, silicato reativo e material em suspensão) e sedimento (granulometria, matéria orgânica, fósforo e nitrogênio) foram analisadas em 8 pontos de amostragem na região litorânea do reservatório. Simultaneamente, exemplares de macrófitas foram fotografados e coletados para identificação, buscando-se uma relação com as características limnológicas, hidrológicas (vazão e tempo de residência) e climatológicas (temperatura do ar, precipitação, vento e radiação). Os resultados da análise das variáveis físicas, químicas e biológicas dos diversos pontos de amostragem mostraram que existe uma diferenciação espacial e temporal no reservatório, verificando-se aumento do grau de trofia do mesmo em relação aos estudos anteriores. Quanto à composição e distribuição das macrófitas, estas se encontram mais concentradas na área alagada formada pelo barramento das águas do rio Itaqueri e ribeirão do Lobo, embora a maior riqueza de espécies tenha ocorrido no ribeirão do Lobo e córrego das Perdizes, sendo mais elevada em comparação com estudos anteriores. A distribuição espacial e temporal das macrófitas aquáticas apresenta relação com as características morfométricas, hidrodinâmicas e com o aporte de nutrientes pelos tributários, além das condições climatológicas, que inserem modificações na dinâmica do reservatório e, conseqüentemente, no estabelecimento e estruturação das comunidades. / The objective of this study was to examine the composition and distribution of aquatic macrophytes species in the Lobo reservoir (Broa) in four periods of the year 2007: March, May, August and November. To achieve the proposed objectives, limnological variables involving water (pH, conductivity, temperature, dissolved oxygen, chlorophyll, nitrogen and phosphated forms and reactive silicate) and sediment (grain, organic matter, phosphorus and nitrogen) compartments were analyzed at 8 sample stations in the littoral region of the reservoir. Meanwhile, samples of macrophytes were photographed and collected for identification, seeking a relationship with the limnological, hydrological (flow and length of residence time) and weather (air temperature, precipitation, wind and radiation) characteristics. The results of physical, chemical and biological variables of the various sample points showed that there is a spatial and temporal differentiation in the reservoir, verifying the increasing of the trophic levels in relation to previous studies. As to the composition and distribution of macrophytes, they are more concentrated in the flooded area formed by the barred waters of Itaqueri river and Lobo river, although the greatest wealth of species has occurred in Lobo river and Perdizes, being higher compared with earlier studies. The spatial and temporal distribution of aquatic macrophytes presents relationship with the morphometric and hydrodynamic characteristics and intake of nutrients by the rivers, in addition to climatic conditions, which inserts changes in the dynamics of the reservoir and, consequently, the establishment and structure of communities.

La Seine est un écosystème profondément affecté par les activités humaines. Il a subi des changements améliorant le traitement des eaux usées parisiennes et les apports diffus de l'agriculture. Des campagnes de prélèvements en profils longitudinaux ont été menées à l'amont et à l'aval de la station d'épuration Seine-Aval (step SAV) pour décrire la dynamique de l'azote et des activités des micro-organismes nitrifiants et la comparer aux observations disponibles antérieures à l'implémentation d'un traitement de l'azote. Les résultats prouvent que la step SAV rejette moins d'ammonium et plus d'organismes nitrifiants mais avec un développement plus lent et moins important qui disparaissent en aval améliorant le déficit en oxygène en Seine. De plus, le bilan et le rôle du phosphore ont été démontrés avec des apports au milieu fluvial diminués d'un facteur 2.7 depuis le début des années 2000. La mesure expérimentale des paramètres de l'adsorption du phosphore sur la matière en suspension a permis d'affirmer que ceux-ci sont influencés par les rejets des stations d'épuration mettant en oeuvre un traitement du phosphore. Nous montrons, par modélisation, que la dynamique de développement des algues est sensible au processus d'adsorption du phosphore. Les changements apparus dans la fréquence et l'intensité des blooms algaux en Seine peuvent s'expliquer par la réduction de la charge ponctuelle en phosphore. Avec des concentrations en orthophosphates proches de la limitation dans les secteurs amont, une modélisation précise de l'apparition du phytoplancton à l'échelle du bassin versant reste cependant encore difficile avec les outils mécanistiques actuels que nous avons développés. / The Seine river system is an ecosystem deeply affected by human activities. The new water quality requirements have led to significant changes. We provided an overview of nitrogen transfers in the Seine basin. We conducted sampling campaigns in order to describe the dynamics of nitrogen and nitrification. Furthermore, we compared our results with the observations before the implementation of nitrogen treatment at the wastewater treatment plant Seine Aval (WWTP SAV). The results proved that the WWTP discharges less ammonium and more nitrifiers but with a slower development than before. These communities disappear downstream, without causing low oxygen concentrations in the lower Seine and its estuary, as they did before... A simplified modelling of nitrogen concentrations and nitrification before and after the implementation of nitrogen treatment helped to reproduce the past and the present trends.Moreover, the assessment of the fluxes and the analysis of the role of phosphorus were realized. The inputs to the river system have been reduced almost three times in the early year 2000. The experimental measurement of phosphorus sorption characteristics onto suspended solids has shown that particles could be affected by the discharges coming from the WWTP SAV after the introduction of an advanced treatment. We show also by modelling, that the algal growth is very sensitive to adsorption process. The changes in frequency and amplitude of algal blooms observed in the Seine can be explained by the reduction of point phosphorus loadings. The modelling of algal blooms throughout the entire basin remains difficult with the currently available mechanistic tools.

Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol) / Heavy metals and nutrients have long been regarded as pollutants to freshwater ecosystems. These elements have a detrimental effect on plants, animals and the water quality of rivers in South Africa. The Berg River flows from the mountains of Franschhoek to the West Coast of the Western Cape. It is an important river in Cape Town, as it is essential for water distribution to town, for agriculture and industry and also supports a rich diversity of organisms in the ecosystem. Along the river, many farms and towns are situated and many tributaries enter the river. The Berg River dam provides for a water supply during the drier periods of the year. Therefore it is crucial to maintain a good water quality. The study was driven by the need to increase the knowledge of water quality in the upper Berg River after the construction of a new major Berg River dam, constructed in 2007. This study investigated oxygen, water temperature, electrical conductivity, pH, ammonium, nitrate, nitrite in the water and cadmium, copper, lead, iron, zinc, potassium, sodium, calcium, magnesium and phosphorus found in water, sediment and three plant species at ten sites along the upper Berg River, Western Cape. The results showed that the electrical conductivity, pH and the concentrations of nitrate, calcium and magnesium increased downstream, whereas the water temperature decreased downstream. Nitrate, cadmium, copper, potassium, sodium, calcium and magnesium displayed a general increase towards the colder period in the water. Seasonally, copper and magnesium showed significant winter increase within the sediment. Nitrogen, iron and calcium levels within Salix sp., Acacia mearnsii and Brabejum stellatifolium increased downstream. Nitrogen, cadmium, copper, potassium, calcium, magnesium and phosphorus in the three species were higher in the warmer seasons and decreased in the colder. Sources of pollution stem from the Franschhoek and Dwars tributaries, urban and farm runoff.

Currently 35 per cent of the total water storage available in South African dams has deteriorated in water quality due to excessive nutrient loading. Eutrophication poses a significant threat to freshwater resources in South Africa. Although there are policies in place to deal with this threat, the problem of eutrophication still persists. The main goal of this study was to investigate the existence of tradeoffs between the different economic costs associated with eutrophication in the Vaal River System. This was done with the aim of understanding the water quality management policy implications that follow as a result of the existence of tradeoffs between the different economic costs associated with eutrophication in the Vaal River System. This study contributed to the understanding of the current and historic impact of eutrophication on the Vaal River System. Using Seemingly Unrelated Regressions (sample period 1996 – 2006), similar to De Villiers (2009) and Mostert (2009), this study revealed that the impact of eutrophication on property prices in the study areas was not discernible. This study further confirmed that eutrophication had an economic impact on agriculture and water treatment. Future research is necessary to estimate coefficients in the case of extreme eutrophication level changes. Estimation techniques such as System Wide Dynamic Modelling, which combines traditional data and expert opinion, can capture the impacts of extreme eutrophication level changes. / Dissertation (MCom)--University of Pretoria, 2013. / Economics / unrestricted

Eutrophication is defined as the ‘over enrichment’ of a water body from nutrients, resulting in uncontrolled growth of primary producers, leading to periods of oxygen depletion from decomposition of the algal organic matter. According to the 2010 Water Infrastructure Needs and Investment (a U.S. Congressional Report), 40% of U.S. water bodies are contaminated with pollutants, including nutrients. Non-point sources of nutrient pollution are a major cause of this reduction in water quality. One way to decrease eutrophication is to manage nutrients found in stormwater runoff, before they reach a receiving water body. Bioretention cells containing an internal water storage zone (IWSZ) have been shown to remove higher amounts of nitrogen than conventional cells (without an IWSZ). The IWSZ contains an organic carbon substrate, usually derived from wood chips submerged in water, which supports the biochemical process of denitrification. Characteristics of wood chips that affect nitrogen removal include carbon content (%), leaching of dissolved organic carbon (DOC), and wood chip size and type. However, there is limited information on how the intermittent hydraulic loading that is associated with these field systems impacts their performance. Accordingly, the overall goal of this research is to improve understanding of the effect that the antecedent dry conditions (ADC) have on the performance of a field scale bioretention cell modified to contain an IWSZ. The nine different types of wood chips used in laboratory and field studies identified in the literature were categorized as hardwood and softwood. Literature showed that total organic carbon (TOC) leached from softwood chips is almost double the TOC measured from the hardwood chips, 138.3 and 70.3 mg/L, respectively. The average observed nitrogen removal for softwood chips was found to be greater than the removal for the average of the hardwood chips (75.2% and 63.0%, respectively). Literature also suggests that larger wood chip size may limit the availability of the carbon for the denitrifying organisms and provides less surface area for the biofilm growth. A field study conducted for this research compared the performance of a modified bioretention system designed to enhance denitrification, addition of an IWSZ, with a conventional system that does not contain an IWSZ. Fourteen storm events were completed from January 2016 to July 2016 by replicating storm events previously completed in the laboratory using hydraulic loading rates (HLR) of 6.9 cm/h, 13.9 cm/h, and 4.1 cm/h. The goal was to have results from storm events with ADCs of two, four, and eight days, with the varying durations of hydraulic loading of two, four, and six hours. Synthetic stormwater, simulating nitrogen levels common in urban runoff, was used as the system’s influent to assist in running a controlled experiment. The resultant ADCs ranged from 0 to 33 days, with the average ADC being 9 days. The fourteen sets of influent samples were averaged to obtain mean influent concentrations for the synthetic stormwater. These values were used when calculating the percent nitrogen removal for the four measured nitrogen species (NOx – N, NH4+– N, organic N, and TN). The field storm events were separated into three groups based on HLR and duration to eliminate the affects of both variables on nitrogen removal for these results, since the focus is the ADC. For the low HLR (4.1 cm/hr), there were four storm events (ADCs of 4 to 33 days), as the ADC increased, greater percentages of ammonium – nitrogen, organic nitrogen, and total nitrogen were removed. For nitrate/nitrite – nitrogen, the percent removal was rather consistent for all four storm events, not significantly increasing or decreasing with changes in the ADC. There were five storm events (ADCs of 0 to 28 days) tested with the median HLR (6.9 cm/hr), nitrogen removal for all four species increased as the ADC increased. The increase was significant (p0.05) for nitrate/nitrite – nitrogen. The third group also contained five storm events (ADCs from 0 to 11 days) that were tested with the highest HLR (13.9 cm/hr). Ammonium – nitrogen, nitrate/nitrite – nitrogen, and total nitrogen all increased with the ADC, and organic nitrogen removal decreased with the increasing ADC. As a result, this research concluded that the difference in HLR affects the nitrogen removal efficiency, but overall increasing the ADC increased nitrogen removal for NOx – N, NH4+ - N, organic N, and TN.