Ecosystems and their components (e.g., organisms, physicochemical variables) are dynamic in space and time. This dynamism makes ecological change notoriously difficult to study and manage. This thesis therefore aims to develop new ways of using spatiotemporal information for inference and prediction. Applying theoretical and statistical concepts to patterns of spatiotemporal variation in aquatic ecosystems led to three discoveries that show promise as ecological applications. First, I show that temporal variability of an ecosystem process can be inferred from its spatial variability. This application may be the first quantitative form of the widely-used method, space-for-time substitution. Its use is supported by an analytical framework giving the conditions under which space is a good surrogate for time. Second, I demonstrate the use of spatiotemporal patterns to predict responses of variables when ecosystem fragments are connected. Connection leads to large shifts in spatiotemporal pattern and other response metrics (e.g., temporal variability) for variables showing asynchrony and concentration gradients among sites (e.g., populations). Meanwhile, these changes are minimal if variables exhibit synchrony and homogeneity across space (e.g., energetic variables). A final discovery is that temporal attributes like stability are strong predictors of persistent spatial variation – a pattern that reflects how reliably resource concentrations occur in the same locations. This finding suggests the potential of time-for-space substitution, where one or few well-resolved time series could be used to infer landscape patterns. All but one of the tested approaches were data efficient and broadly-applicable across ecosystems and ecological processes. They thus contribute new possibilities for prediction when data are scarce, as well as new perspectives on dynamics in multi-variable landscapes. Research here shows that work at the intersection of spatial and temporal pattern can strengthen the interpretation of ecosystem dynamics and, more generally, foster synthesis from populations to landscapes. / Thesis / Doctor of Philosophy (PhD) / The physical and biological components of ecosystems are constantly in flux, varying in value among locations (spatially) and over time (temporally). This dynamism makes it difficult to predict current or future behaviours of ecological variables (e.g., population size). This thesis tests the potential of using spatial and temporal patterns to make inferences and predictions about changes in ecological systems. I tested three new theory-based tools in aquatic ecosystems, finding that: The size of temporal fluctuations in an ecosystem variable can be predicted from the size of value-differences among locations; spatial and temporal patterns can predict how a variable responds when isolated fragments of ecosystems are connected; and attributes of ecosystem variables (e.g., their stability) can indicate the likelihood of resources recurring in the same location. Findings show that new insight into spatial and temporal patterns can help prediction and management in complex landscapes.

Tema importante no estudo da ecologia, a competição inter-específica é a demanda ativa por indivíduos de duas ou mais espécies de mesmo nível trófico por um recurso comum que é potencialmente limitante. Esse estudo teve como objetivo avaliar a ocorrência de competição entre espécies de microcrustáceos cladóceros e seu papel na estruturação da comunidade zooplanctônica. Este elo é o que faltava para completar o modelo conceitual sobre interações no Lago Monte Alegre. Foram selecionadas duas espécies de microcrustáceos cladóceros coexistentes e abundantes no lago, Ceriodaphnia richardi e Daphnia gessneri. Dois experimentos de competição foram realizados, sendo utilizadas concentrações diferentes de alimento (0,70 mgC.L-1, 0,25 mgC.L-1 da clorofícea cultivada, Scenedesmus spinosus) para alimentar os cladóceros. Os tratamentos foram (3 réplicas cada): a. controle com Ceriodaphnia richardi em frascos individuais; b. controle com Daphnia gessneri em frascos individuais; c. duas espécies colocadas no mesmo frasco. Todos os experimentos foram conduzidos sob temperatura controlada de 23ºC, que representa a temperatura média anual no lago. A taxa de crescimento (r) por dia foi calculada pela equação exponencial: r = (ln Nt - ln No)/t, onde No e Nt são as densidades inicial e final, respectivamente, e t é o tempo em dias. A maior concentração de alimento favoreceu o crescimento populacional das duas populações estudadas. C. richardi não teve seu crescimento influenciado pela presença de D. gessneri, superando-a em termos de densidade e taxas de crescimento. Já D. gessneri teve sua taxa de crescimento populacional influenciado pela presença de C. richardi, na menor concentração de alimento. Para melhor compreender as razões da superioridade competitiva de C. richardi e o papel da predação com relação a essa espécie, foram feitos experimentos adicionais. Um deles testou a hipótese de que essa espécie pode alimentar-se de outros recursos além de algas, com os tratamentos (3 réplicas): a. água filtrada do lago e b. água filtrada, com adição da alga S. spinosus. Os resultados deram suporte à hipótese. O experimento de predação, com 5 cladóceros e 2 larvas IV de Chaoborus por réplica, mostrou que essa espécie é predada por elas. Flutuações das populações de microcrustáceos zooplanctônicos e dos predadores invertebrados (larvas de Chaoborus brasiliensis e o ácaro aquático Krendowskia sp.) foram acompanhadas semanalmente no lago, durante um ano, entre maio de 2011 e abril de 2012, bem como fatores físicos, químicos e biológicos, como temperatura, oxigênio dissolvido, condutividade elétrica, pH, transparência na coluna dágua e clorofila-a, na tentativa de estabelecer conexão entre os resultados de laboratório e campo. Os resultados mostraram que um período de estratificação térmica mais nítida ocorreu no lago entre outubro e abril (estação quente-chuvosa), sendo mais acentuada a partir de dezembro, enquanto circulação freqüente da coluna dágua foi registrada nos meses mais frios do ano, de maio a setembro (estação fria-seca). A distribuição vertical de outras variáveis ambientais mostrou relação com o padrão de circulação do lago, refletindo na dinâmica populacional das populações zooplanctônicas. Cladóceros foram mais abundantes na estação fria-seca, enquanto copépodos aumentaram no início da estação quente-chuvosa. Porém, ambos os grupos apresentaram as menores densidades entre os meses de fevereiro e abril de 2012. O aumento das larvas de caoborídeos e dos ácaros aquáticos na estação quente-chuvosa parece ser a principal causa do declínio de cladóceros neste período, devido à predação. Já o alimento e temperatura parecem ter maior influência sobre as populações na estação fria-seca. Além da predação, temperatura e alimento, os resultados de competição inter-específica também mostraram ser esse um dos fatores potencialmente controladores da dinâmica populacional do zooplâncton no Lago Monte Alegre, particularmente no período frio, quando o alimento é mais escasso. / Competitive interactions are an important topic in the study of ecology. The interspecific competition is the demand for active individuals of two or more species of the same trophic level for a common resource that is potentially limiting. This study aimed to evaluate the occurrence of competition between species of cladocerans and their role in structuring the zooplankton community. This is the missing link to complete the conceptual model on interactions in the Lake Monte Alegre. Two species of abundant cladocerans that coexist in the lake were selected, Ceriodaphnia richardi and Daphnia gessneri. Two competition experiments were carried out, using different concentrations (0.70 mgC.L-1 and 0.25 mgC.L-1) of the cultivated chlorophycean Scenedesmus spinosus. The treatments were (with 3 replicates each): a. control with Ceriodaphnia richardi in individual bottles; b. control with Daphnia gessneri in individual bottles; c. the two species placed in the same bootle. All experiments were conducted under controlled temperature of 23 ºC, which represents the average annual temperature in the lake. The growth rate (r) per day was calculated by the exponential equation: r = (ln Nt - ln No)/t, where No and Nt are the initial and final densities, respectively, and t is time in days. Increased population growth of the two populations occurred in the highest concentration of food. The growth of C. richardi was not influenced by the presence of D. gessneri, exceeding it in terms of density and growth rates. The population growth of D. gessneri was also influenced by the presence of C. richardi in the lowest concentration of food. For a better understanding of the reasons for the competitive superiority of C. richardi and the role of predation related to this species, two additional experiments were made. For testing the hypothesis that the species exploits other food resources, the treatments were (3 replicates): a. with lake filtered water and b. with filtered water + alga S. spinosus. The results supported the hypothesis. The predation experiment with 5 cladocerans and 2 larva IV of Chaoborus per replicate showed that the species is preyed on by the larvae. The fluctuations of zooplanktonic microcrustaceans and invertebrate predators (Chaoborus brasiliensis larvae and aquatic mite Krendowskia sp.) were monitored weekly in the lake during one year, from May 2011 to April 2012. Physical, chemical and biological factors, such as temperature, dissolved oxygen, electrical conductivity, pH, transparency in the water column and chlorophyll-a were monitored in an attempt to establish a link between the results of laboratory and field. The results showed that the period of more stable thermal stratification in the lake occurred between October and April (warm-wet season). A more stable stratification started in December, while more frequent circulation of the water column was recorded during the coldest months of the year, from May to September (cold- dry season). The vertical distribution of other environmental variables are a consequence of the lake circulation pattern. Cladocerans were more abundant in the cold-dry season, while copepods increased in early warm-wet season. However, both groups had the lowest densities between February and April 2012. Increased densities of chaoborid larvae and water mites in the warm-wet season seem to be the main cause of the decline of cladocerans in this period due to predation. Food and temperature can exert greater influence on populations in the cold-dry season. In addition to predation, temperature, and food, the results of interspecific competition indicated that it may be one of the factors controlling the population dynamics of zooplankton in the Lake Monte Alegre in periods of food shortage, particularly in the cool period.

The spatial distribution and monthly fluctuation of beetle species were studied in the experimental forests of Liu-Kuei Station, Taiwan Forestry Research Institute, Taiwan. Beetles were surveyed using pitfall traps from January to December, 2004. Our result showed that species richness, abundance and Shannon diversity of beetles were significant higher in Natural Forest than those of the others, and species richness and abundance were lowest in Taiwania Plantation. The composition and trophic structure of beetle community in the Thinning Plantation resulting from thinning were compared with that in the Taiwania Plantation and natural forest. Beetles communities of Natural Forest, Taiwania Plantation and Thinning Plantation were separated from each other by ordination (PCA), meaning three forest stands have distinct species assemblages. The three group assemblages were also revealed by cluster analysis. The ground-surface air humidity, litter litter depth and herbs cover were major environment factors influencing the beetle distribution. The relative size of trophic guilds in the Thinning Plantation has changed compared to Taiwania Plantation. Detritivores increased significantly in the Thinning Plantation, suggested an increase of nutrient-cycle in the Plantation. Eight dominant beetle families that were Carabidae, Scarabaeidae, Curculionidae, Staphylinidae, Scydmaenidae, Erotylidae, Nitidulidae and Biphyllidae showed different pattern of population fluctuation. The peak mainly from March to June, and Curculionidae, Scarabaeidae, Nitidulidae also show a moderate peak in August and September. In the two plantation areas, most dominant taxa showed a similarly fluctuation patterns, which are slightly different to those of Natural Forest.

Tema importante no estudo da ecologia, a competição inter-específica é a demanda ativa por indivíduos de duas ou mais espécies de mesmo nível trófico por um recurso comum que é potencialmente limitante. Esse estudo teve como objetivo avaliar a ocorrência de competição entre espécies de microcrustáceos cladóceros e seu papel na estruturação da comunidade zooplanctônica. Este elo é o que faltava para completar o modelo conceitual sobre interações no Lago Monte Alegre. Foram selecionadas duas espécies de microcrustáceos cladóceros coexistentes e abundantes no lago, Ceriodaphnia richardi e Daphnia gessneri. Dois experimentos de competição foram realizados, sendo utilizadas concentrações diferentes de alimento (0,70 mgC.L-1, 0,25 mgC.L-1 da clorofícea cultivada, Scenedesmus spinosus) para alimentar os cladóceros. Os tratamentos foram (3 réplicas cada): a. controle com Ceriodaphnia richardi em frascos individuais; b. controle com Daphnia gessneri em frascos individuais; c. duas espécies colocadas no mesmo frasco. Todos os experimentos foram conduzidos sob temperatura controlada de 23ºC, que representa a temperatura média anual no lago. A taxa de crescimento (r) por dia foi calculada pela equação exponencial: r = (ln Nt - ln No)/t, onde No e Nt são as densidades inicial e final, respectivamente, e t é o tempo em dias. A maior concentração de alimento favoreceu o crescimento populacional das duas populações estudadas. C. richardi não teve seu crescimento influenciado pela presença de D. gessneri, superando-a em termos de densidade e taxas de crescimento. Já D. gessneri teve sua taxa de crescimento populacional influenciado pela presença de C. richardi, na menor concentração de alimento. Para melhor compreender as razões da superioridade competitiva de C. richardi e o papel da predação com relação a essa espécie, foram feitos experimentos adicionais. Um deles testou a hipótese de que essa espécie pode alimentar-se de outros recursos além de algas, com os tratamentos (3 réplicas): a. água filtrada do lago e b. água filtrada, com adição da alga S. spinosus. Os resultados deram suporte à hipótese. O experimento de predação, com 5 cladóceros e 2 larvas IV de Chaoborus por réplica, mostrou que essa espécie é predada por elas. Flutuações das populações de microcrustáceos zooplanctônicos e dos predadores invertebrados (larvas de Chaoborus brasiliensis e o ácaro aquático Krendowskia sp.) foram acompanhadas semanalmente no lago, durante um ano, entre maio de 2011 e abril de 2012, bem como fatores físicos, químicos e biológicos, como temperatura, oxigênio dissolvido, condutividade elétrica, pH, transparência na coluna dágua e clorofila-a, na tentativa de estabelecer conexão entre os resultados de laboratório e campo. Os resultados mostraram que um período de estratificação térmica mais nítida ocorreu no lago entre outubro e abril (estação quente-chuvosa), sendo mais acentuada a partir de dezembro, enquanto circulação freqüente da coluna dágua foi registrada nos meses mais frios do ano, de maio a setembro (estação fria-seca). A distribuição vertical de outras variáveis ambientais mostrou relação com o padrão de circulação do lago, refletindo na dinâmica populacional das populações zooplanctônicas. Cladóceros foram mais abundantes na estação fria-seca, enquanto copépodos aumentaram no início da estação quente-chuvosa. Porém, ambos os grupos apresentaram as menores densidades entre os meses de fevereiro e abril de 2012. O aumento das larvas de caoborídeos e dos ácaros aquáticos na estação quente-chuvosa parece ser a principal causa do declínio de cladóceros neste período, devido à predação. Já o alimento e temperatura parecem ter maior influência sobre as populações na estação fria-seca. Além da predação, temperatura e alimento, os resultados de competição inter-específica também mostraram ser esse um dos fatores potencialmente controladores da dinâmica populacional do zooplâncton no Lago Monte Alegre, particularmente no período frio, quando o alimento é mais escasso. / Competitive interactions are an important topic in the study of ecology. The interspecific competition is the demand for active individuals of two or more species of the same trophic level for a common resource that is potentially limiting. This study aimed to evaluate the occurrence of competition between species of cladocerans and their role in structuring the zooplankton community. This is the missing link to complete the conceptual model on interactions in the Lake Monte Alegre. Two species of abundant cladocerans that coexist in the lake were selected, Ceriodaphnia richardi and Daphnia gessneri. Two competition experiments were carried out, using different concentrations (0.70 mgC.L-1 and 0.25 mgC.L-1) of the cultivated chlorophycean Scenedesmus spinosus. The treatments were (with 3 replicates each): a. control with Ceriodaphnia richardi in individual bottles; b. control with Daphnia gessneri in individual bottles; c. the two species placed in the same bootle. All experiments were conducted under controlled temperature of 23 ºC, which represents the average annual temperature in the lake. The growth rate (r) per day was calculated by the exponential equation: r = (ln Nt - ln No)/t, where No and Nt are the initial and final densities, respectively, and t is time in days. Increased population growth of the two populations occurred in the highest concentration of food. The growth of C. richardi was not influenced by the presence of D. gessneri, exceeding it in terms of density and growth rates. The population growth of D. gessneri was also influenced by the presence of C. richardi in the lowest concentration of food. For a better understanding of the reasons for the competitive superiority of C. richardi and the role of predation related to this species, two additional experiments were made. For testing the hypothesis that the species exploits other food resources, the treatments were (3 replicates): a. with lake filtered water and b. with filtered water + alga S. spinosus. The results supported the hypothesis. The predation experiment with 5 cladocerans and 2 larva IV of Chaoborus per replicate showed that the species is preyed on by the larvae. The fluctuations of zooplanktonic microcrustaceans and invertebrate predators (Chaoborus brasiliensis larvae and aquatic mite Krendowskia sp.) were monitored weekly in the lake during one year, from May 2011 to April 2012. Physical, chemical and biological factors, such as temperature, dissolved oxygen, electrical conductivity, pH, transparency in the water column and chlorophyll-a were monitored in an attempt to establish a link between the results of laboratory and field. The results showed that the period of more stable thermal stratification in the lake occurred between October and April (warm-wet season). A more stable stratification started in December, while more frequent circulation of the water column was recorded during the coldest months of the year, from May to September (cold- dry season). The vertical distribution of other environmental variables are a consequence of the lake circulation pattern. Cladocerans were more abundant in the cold-dry season, while copepods increased in early warm-wet season. However, both groups had the lowest densities between February and April 2012. Increased densities of chaoborid larvae and water mites in the warm-wet season seem to be the main cause of the decline of cladocerans in this period due to predation. Food and temperature can exert greater influence on populations in the cold-dry season. In addition to predation, temperature, and food, the results of interspecific competition indicated that it may be one of the factors controlling the population dynamics of zooplankton in the Lake Monte Alegre in periods of food shortage, particularly in the cool period.

Introduction: The Chattahoochee River and its lakes and tributaries are essential resources for metro-Atlanta; however, urbanization and other human impacts near these resources affects the quality of water. The objectives of this study are to describe the spatial and temporal patterns of Escherichia coli (E. coli), and examine the relationship between rainfall and E. coli levels in metro-Atlanta surface waters, including the Chattahoochee River and its lakes and tributaries. Methods: The water quality data used for the study was originally collected and analyzed by the Chattahoochee Riverkeeper (CRK) Neighborhood Water Watch (NWW) program. For this analysis, sites with a total of 50 samples or more were subjected to descriptive analysis. Results: Twenty-seven of the 36 sites had a mean E. coli concentration exceeding the US EPA’s recreational water quality criteria of 2.37 log Most Probable Number per 100 milliliters. Sites with the highest and lowest mean E. coli levels were located, on average, 2.77 and 20.22 miles from downtown Atlanta, respectively. Spikes in E. coli levels occurred 99 counts of 699 sampling events in the winter, 168/827 spring, 141/877 summer, and 170/950 fall. Seven of the 36 sites were analyzed to examine the relationship between 48-hour rainfall and E. coli levels. Four sites indicated that there was a significant positive correlation between the two variables. (r=0.52, p<.0001; r=0.67, p<.0001; r=0.39, p<.0001; r=0.38, p<.0001) Discussion: The water quality in waterways closer to downtown may be attributable to combined sewer overflows and the urbanization and land use associated with the city. Overall, there was temporal variation in E. coli concentrations, however there was no distinct seasonal pattern. The relationship between 48-hour rainfall and E. coli levels of four of the seven sites analyzed was consistent with other studies.

O presente estudo visou caracterizar as variações nictemerais e sazonais na estrutura da comunidade fitoplanctônica do sistema australiano de lagoas de estabilização, localizado no município de Novo Horizonte, SP, por meio de análises de abundância, biomassa, densidade, riqueza e de índices de diversidade, dominância e equidade. Para a realização desse objetivo, as amostras foram coletadas nas lagoas facultativa 1 e facultativa 2 e no efluente final, em quatro épocas: maio/2002 – outono, agosto/2002 – inverno, novembro/2002 – primavera e fevereiro/2003 – verão, a cada seis horas, durante vinte e quatro horas, no total de cinco amostragens (t0, t1, t2, t3 e t4), com início aproximadamente às 9:30 horas; com exceção do efluente final, que foi coletado apenas em t0 e t4. Nestes dois horários também foram coletadas amostras na entrada e na saída da lagoa anaeróbia, para avaliação da eficiência do sistema. Além das variáveis biológicas foram realizadas análises de material em suspensão, nutrientes (nitrogênio total e amoniacal, nitrito, nitrato, fósforo e ortofosfato), oxigênio dissolvido, pH, condutividade elétrica da água, DBO e transparência da água. Foram encontrados organismos pertencentes às classes Chlorophyceae, Cyanophyceae, Euglenophyceae e Bacillariophyceae. Chlorophyceae foi a que mais contribuiu para a riqueza, densidade e biomassa em quase todos os períodos de estudo; mais de 40% da riqueza foi representada por ela e sua maior densidade foi registrada a 0,7 m de profundidade na lagoa facultativa 1, em t3, no inverno (875.834,7 org/ml). Entre as espécies dessa classe, a predominante, em todas as épocas de coleta, foi Chlorella vulgaris, considerada dominante no inverno e abundante nas demais estações. Os outros organismos, no entanto, foram somente comuns, ocasionais ou raros. Apesar de ter sido observada estratificação térmica em alguns horários de coleta, principalmente em t1 (por volta das 15:00h), esta não foi duradoura, talvez por se tratar de um sistema raso. Portanto, pode-se considerar que o ambiente manteve-se homogêneo em relação à comunidade algal ao longo da coluna de água / The aim of this study were to characterize the seasonal and diary cycle variations of the phytoplankton in waste stabilization ponds from Novo Horizonte, SP. The sample were collected in 1 and 2 facultative ponds and effluent in four times: may/2002 – autumn, august/2002 – winter, november/2002 – spring, february/2002- Summer, each six hours in cycle diary. Were analysed abundance, biomass, densith, wealth and diversity index of phytoplankton, chlorophyll a, pheopigments, suspended solids, nutrients, dissolvid oxygen, pH, biochimical oxygen demand, electric conductivity and water’s transparence. The groups meet were: Chlorophyceae, Cyanophyceae, Euglenophyceae and Bacillariophyceae. Chlorophyceae contribute with bigger wealth, density and biomass; of the kinds this group, Chlorella vulgaris, were prevalent, recognized since dominant in the winter and abundant in others seasons. The other organisms, however, were commons, occasionalls or rares. The environment of ponds remain homogeneous in relation to the algal community

A bacia hidrográfica do Arroio Candiota está situada no sudoeste do Estado do Rio Grande do Sul, Brasil. Sofre intensa atividade antrópica, como mineração de carvão e calcário, pecuária, silvicultura e agricultura. Apresenta ainda em seu território a Usina Termelétrica Presidente Médici - UTPM - Candiota II. Este trabalho teve como objetivo analisar a variação temporal da comunidade zooplanctônica, representada por Rotifera, Cladocera e Copepoda, a partir das variáveis ambientais e atributos funcionais em alguns arroios impactados pelos diferentes usos da bacia hidrográfica do Arroio Candiota. Foram realizadas coletas trimestrais de água e zooplâncton com o intuito de caracterizar as estações climáticas do ano, durante o período de abril/2007 a outubro/2014. As coletas ocorreram em sete estações amostrais diferentes, totalizando 161 unidades amostrais. As variáveis físicas e químicas selecionadas para este trabalho foram pH, turbidez, ferro dissolvido, oxigênio dissolvido e temperatura. Para as análises estatísticas foram utilizados modelos lineares generalizados (GLM), cálculo da diversidade das espécies, que envolveu duas medidas baseadas em distâncias topológicas, a distinção taxonômica (Δ*) e a diversidade taxonômica (Δ), análise de espécies indicadoras (ISA) e análise de atributos indicadores (ITA). Foram identificados 152 táxons ao total das coletas. Rotifera foi predominante com 122 espécies, após Cladocera com 16 espécies e Copepoda com 14 espécies. Os resultados mostraram que o pH foi a única variável que apresentou resultado significativo com valores positivamente proporcionais para a abundância de espécies. Em relação à riqueza de espécies, as variáveis pH, ferro dissolvido e oxigênio dissolvido influenciaram positivamente ao longo do tempo. O cálculo da diversidade e distinção taxonômica demonstrou que das 161 unidades amostrais, 127 mostraram valores de diversidade conforme o esperado ao acaso na natureza. Quatro unidades amostrais apresentaram valores da diversidade acima do esperado e 31 exibiram valores abaixo do esperado ao acaso. A ISA identificou duas espécies indicadoras da estação amostral 1 e cinco espécies indicadoras da estação amostral 2. Foram encontradas cinco espécies indicadoras específicas do inverno, cinco do outono, quatro da primavera e nove espécies indicadoras no verão. A ITA demonstrou que espécies de tamanho C4 (≥ 1000 μm), tiveram maior ocorrência no inverno e primavera. O atributo funcional “coletores e raspadores” foi considerado indicador para as estações amostrais EA1 e EA3 por cinco espécies. Os resultados encontrados não demonstraram um gradiente contínuo de crescimento ou declínio da abundância e riqueza de espécies ao longo do tempo. Assim, a comunidade zooplanctônica parece ser mais fortemente influenciada pelas características naturais de Candiota, como relevo e rede de drenagem, com exceção dos riachos que recebem diretamente efluentes da mineração de carvão. / The Arroio Candiota watershed is located in the southwestern state of Rio Grande do Sul, Brazil. It suffers intense human activity, such as mining of coal and limestone, livestock, forestry and agriculture. It also presents in its territory the Thermoelectric Plant Presidente Medici - UTPM - Candiota II. This study aimed to analyze the temporal variation of zooplankton community, represented by Rotifers, Cladocera and Copepoda, from the environmental variables and functional attributes in some streams impacted by different uses of the Arroio Candiota watershed. Quarterly sampling of water and zooplankton were conducted in order to characterize the seasons of the year, during the period April/2007 to October/2014. The collections occurred in seven different sampling stations, totaling 161 sampling units. The physical and chemical variables selected for this study were pH, turbidity, dissolved iron, dissolved oxygen and temperature. For statistical analysis we used generalized linear models (GLM), calculating the diversity of species, which involved two measures based on topological distances, the taxonomic distinction (Δ*) and taxonomic diversity (Δ), indicator species analysis (ISA) and indicators atributes analysis (ITA). There were identified 152 taxa to the total collections. Rotifera was predominant with 122 species, 16 species of Cladocera and 14 species of Copepoda. The results showed that pH was the only variable that showed significant results with positive values proportional to the abundance of species. The variables pH, dissolved iron and dissolved oxygen positively influenced the richness of species over time. The calculation of diversity and taxonomic distinction showed that of the 161 sampling units, 127 showed diversity of values as expected at random in nature. Four sampling campaigns showed values of diversity than expected and 31 showed values lower than expected by chance. The ISA has identified two indicator species of the sampling station 1 and 5 indicator species of sampling station 2. We found five specific indicator winter species, five in autumn, four in spring and nine summer indicator species. The ITA has shown that species of C4 size (≥ 1000 μm), were more frequent in winter and spring. The functional attribute "collectors and scrapers" was considered indicator for the sampling stations 1 and 3 with five species. The results did not demonstrate a continuous gradient of growth or decline in abundance and species richness over time. Thus, the zooplankton community seems to be more strongly influenced by Candiota natural features like topography and drainage network, except for streams that receive wastewater directly from coal mining.

Orientador: Virgínia Sanches Uieda / Resumo: A remoção da vegetação ripária pode ser uma importante causa de redução da diversidade e alterações na distribuição de invertebrados bentônicos ao longo do curso de riachos. O presente trabalho foi realizado em trechos de terceira ordem de dois riachos, um trecho com mata ripária (fechado) e outro sem (aberto) em cada riacho, e em dois meses da estação seca de dois anos consecutivos, a fim de verificar possíveis alterações espaciais e temporais na estrutura da fauna de invertebrados bentônicos. Também foram coletados dados de 12 variáveis ambientais e analisados junto com a abundância da fauna com o objetivo de verificar a interação entre estes dois grupos de dados na diferenciação entre as quatro amostras realizadas (dois trechos e dois anos, por riacho). A manutenção ou retirada da vegetação ripária não atuou isoladamente sobre a estrutura da fauna de invertebrados bentônicos, a qual foi também influenciada pela posição (montante ou jusante) do trecho fechado e por características estruturais próprias de cada trecho estudado, como presença de intervenções antrópicas nas proximidades (açudes) e tipo de substrato do leito. No riacho que apresenta o trecho fechado a montante, a mata contribui com matéria orgânica em suspensão e detritos vegetais para o trecho aberto a jusante, aumentando a oferta de abrigo e alimento para a fauna, diversificada e abundante nos dois trechos. Por outro lado, a grande quantidade de macrófitas no trecho aberto, localizado a montante no outro riach... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Removal of riparian vegetation can be an important cause of reduced diversity and changes in the distribution of benthic invertebrates along streams. The present work was carried out in third order stretches of two streams, one stretch with riparian (closed) and one without (open) forest in each stream, and in two months of the dry season of two consecutive years, in order to verify possible changes Spatial and temporal changes in the fauna structure of benthic invertebrates. Data were also collected from 12 environmental variables and analyzed together with the abundance of the fauna, in order to verify the interaction between these two data groups in the differentiation between the four samples (two stretches and two years, by stream). The maintenance or removal of riparian vegetation did not act alone on the structure of the benthic invertebrate fauna, which was also influenced by the position (upstream or downstream) of the closed section and by the structural characteristics of each section studied, such as the presence of anthropic Proximities (weirs) and type of substrate of the bed. In the creek that presents the enclosed stretch upstream, the forest contributes with organic matter in suspension and vegetal debris for the open stretch downstream, increasing the offer of shelter and food for the fauna, diversified and abundant in both stretches. On the other hand, the large amount of macrophytes in the open section, located upstream in the other stream, provides a hete... (Complete abstract click electronic access below) / Mestre

Heavy metals are highly persistent in water and have a particular significance in ecotoxicology. Heavy metals loading from the Pearl River are likely to cause significant impacts on the environment in the South China Sea and the West Pacific. In this study, using monthly monitoring data from a water quality monitoring campaign during 2006–2012, the temporal variation and spatial transfer of six heavy metals (lead (Pb), copper (Cu), cadmium (Cd), zinc (Zn), arsenic (As), and mercury (Hg)) in the Pearl River were analyzed, and the heavy metal fluxes into the sea were calculated. During this period, the annual heavy metal loads discharged from the Pearl River into the South China Sea were 5.8 (Hg), 471.7 (Pb), 1524.6 (Cu), 3819.6 (Zn), 43.9 (Cd), and 621.9 (As) tons, respectively. The metal fluxes showed a seasonal variation with the maximum fluxes occurring from June to July. There is a close association between metal fluxes and runoff. The analysis of the heavy metal transfer from the upstream to the downstream revealed that the transfer from the upstream accounted for a major portion of the heavy metals in the Pearl River Delta. Therefore, earlier industry relocation efforts in the Pearl River watershed may have limited effect on the water quality improvement in surrounding areas. It is suggested that watershed-based pollution control measures focusing on wastewater discharge in both upstream and downstream areas should be developed and implemented in the future.

The Lower Karori Reservoir (LKR) is a small, monomictic lake of 2.34 ha situated in the Karori Wildlife Sanctuary (KWS), Wellington. Over the past decade cyanobacterial blooms have become a common occurrence in this water body. In 2005 Anabaena planktonica was detected for the first time in the LKR and this species now forms dense blooms during summer. These blooms are problematic as they reduce aesthetic appeal and have resulted in odour problems for visitors to this high profile wildlife sanctuary. The objectives of this study were to identify key physical, chemical and biological variables influencing phytoplankton dynamics in the LKR and to use ecological models to investigate plausible management options. The key parameters investigated, that may cause bloom formation were; summer stratification, high nutrient levels, and the food web effects of a large population of European perch (Perca fluviatilis). High resolution sampling was carried out every six hours over a 72 hour period during pre-bloom, bloom and post-bloom periods in 2006/7 to elucidate short term temporal and spatial variations in biological and physico-chemical parameters. Quantitative polymerase chain reaction (QPCR) was used to enumerate A. planktonica populations, allowing a large number of samples to be simultaneously evaluated. Algal densities were also estimated using conventional phytoplankton enumeration and chlorophyll a analysis. Water samples were collected for nutrient analysis at discrete depths and profiles were taken for temperature, dissolved oxygen and photosynthetic active radiation. Secchi depth and pH were also measured. Weekly or fortnightly phytoplankton and zooplankton samples and physical variables have been collected at LKR since September 2005 as part of an independent sampling program carried out by the KWS, Waikato University and Cawthron Institute. In this project the 2-year data set was used to assist with analysis of lake processes and for validation of the hydrodynamic-ecological model DYRESM-CAEDYM. Between 12 and 15 February, 2007, electric fishing was undertaken within the LKR. A total of 3,946 P. fluviatilis were removed and the effects on phytoplankton and zooplankton concentrations were investigated. To increase knowledge of the physiology of A. planktonica, laboratory experiments were undertaken using cultures subjected to a range of different light intensities and temperature regimes The phytoplankton assemblage of the LKR shows very distinct temporal variations. Summer stratification occurred in the LKR for ~4 months each summer. During these periods A. planktonica comprised up to 99.9% of the surface phytoplankton population. During isothermy chlorophytes, bacillariophytes and small flagellated dinophytes are co-dominant in the phytoplankton assemblage. The results of the QPCR showed distinct diurnal vertical movement of A. planktonica, with the highest cell concentrations occurring at 1900 hours at the surface. Ammonium (NH4-N) is the dominant species of inorganic nitrogen during periods of stratification, while nitrate (NO3-N) is generally dominant during times of isothermy. Phosphate concentrations at surface and depth remained at low levels throughout the sampling period. The large surface populations of A. planktonica, are probably responsible for the elevated total nitrogen concentrations in surface waters during stratified periods. There appeared to be some short term effects of the P. fluviatilis removal with an increase in large crustaceans (e.g., Daphnia sp.) and a reduction in A. planktonica densities observed in the months following the P. fluviatilis removal. Only a small proportion of the total P. fluviatilis population was removed and it is unlikely that the effects will be long-lasting without subsequent removal steps. However, it seems likely that P. fluviatilis is one of the factors contributing to cyanobacterial blooms and management of this fish species should be considered in future lake restoration plans. Growth experiments indicated A. planktonica grow over a wide range of light intensities and temperatures, although highest growth rates were generally associated with higher temperatures (25 C) and light intensities (60 - 140 μmol m-2 s-1). Ecological and hydrodynamic trends within the LKR over a two year period were simulated with adequate success using the model DYRESM-CAEDYM. Management scenarios simulated using DYRESM-CAEDYM suggest implementation of an artificial destratification system in the LKR may be the most practical and effective means of controlling A. planktonica blooms. The addition of an artificial aeration system emitting air at a rate of approximately 50 l-1 s-1 should result in an isothermal system. Without summer stratification some of the physiological features of A. planktonica (e.g., buoyancy regulation and nitrogen-fixation) that give it a competitive advantage over other phytoplankton species will be reduced.