Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

There is a number of measures, which have been currently performed on the Brno Reservoir, with the aim at the recovery of the environment health and at the reduction of incidence of cyanobacterial water blooms. The main intervention in this efforts was the desrease of water level in 2009-2010, when the level was reduced by up to 9 m. This intervention resulted in drying of the uncovered area of the littoral bottom and in completely changed oxygen conditions in the remaining lake. The objective of my work is to evaluate changes in benthic macroinvertebrate assemblage in response to these interventions and measures. On the sites of the reservoir, selected with respect to water levels and in-depth ratios, macroinvertebrates were seasonally sampled by the Ekman grab and kick-off approach in deep muddy sites and in the littoral zone, resepctively. Samples were collected at the ?Hráz?, ?Střed?, ?Litorál?, ?Rakovec?, ?Zouvalka?, ?Rokle? and ?Horní vzdutí?. In parallel with sampling selected environmental parameters (temperature, O2) in epilimnium hypolimnium were measured. The samples were washed and conserved for later determination and quantification in the laboratory. All macroinvertebrate samples were divided into three groups: Chironomidae, Oligochaeta and Others. The result are presented in a graphical form as the biomass and density on different sites according to the years preceding the reservoir draining, during the water level decline and afterwards and discussed in association with certain abiotic factors.

Made available in DSpace on 2014-06-11T19:30:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-03-07Bitstream added on 2014-06-13T19:39:34Z : No. of bitstreams: 1 oliveira_pcr_me_botib.pdf: 1401244 bytes, checksum: d0a5231ce70e9cbfd5be0c6439c81f73 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Os rios de pequeno e médio porte são os ecossistemas aquáticos altamente representativos no estado de São Paulo que, tendo a maior produção econômica e maior densidade demográfica do país, sofre com a intensa degradação ambiental. A análise integrada das características da água, do sedimento e da comunidade de macroinvertebrados bentônicos e fundamental para a determinação da qualidade dos ambientes lóticos. 0 presente trabalho buscou avaliar características limnológicas gerais da água e sedimento, bem como a fauna de macroinvertebrados bentônicos dos principais rios do município de Botucatu e região (Capivara, Lavapés, Araquá e Pardo). Os estudos foram feitos em dois períodos do ano: chuvoso (março/2007) e seco (setembro/2007). A largura, profundidade, vazão e temperatura da água aumentaram no sentido jusante; a velocidade, transparência da água e oxigênio dissolvido foram maiores nos trechos à montante; a luminosidade foi total na maioria das estações de amostragem e o pH foi ácido em todos os rios estudados. As estações que sofrem maior impacto de fontes de poluição (rio Lavapés e Araquá) apresentaram os maiores valores de condutividade elétrica, material em suspensão (orgânico e inorgânico), nitrogênio total, nitrato, nitrito, amônia fósforo total, fosfato total dissolvido (orgânico e inorgânico), DBO e coliformes termotolerantes. A maior concentração de silicato foi encontrada no rio Capivara e está relacionada com os intensos processos erosivos na bacia. No período chuvoso a condutividade elétrica, turbidez, material em suspensão foram maiores, enquanto que a clorofila- a foi maior no período seco. Foram encontrados 151 táxons e abundância máxima de 116.481 ind/m2 . Chironomidae apresentou a maior riqueza, seguido... / Rivers and streams of low and medium orders are among the most important aquatic ecosystem of Sao Paulo. This State has the highest economical production and demographic density of the country. Thus, these environments are under severe degradation. Integrated analyses of water, sediment and benthic macroinvertebrates are essential in the assessment of freshwater quality. This study aimed to assess the environmental quality and structure of benthic macroinvertebrates of the main rivers and streams of Botucatu (SP) (Capivara, Lavapes, Araqua and Pardo) and adjacent region. The fieldwork was carried out in rainy (March/207) and dry (September/2007) seasons. Channel width, depth, water velocity and temperature increased towards the rivers mouth. Velocity, water transparency and dissolved oxygen were higher in the upstream sampling stations, light penetration was total in most sampling stations and pH was acid in all studied streams. The most impacted sampling stations, basically by pollution sources (Lavapés and Araquá Rivers), exhibited the highest values of electric conductivity, suspended matter (organic and inorganic), total nitrogen, nitrate, nitrite, ammonium, total dissolved phosphorus (organic and inorganic), BOD and thermotolerant coliforms. Higher silicate concentrations were observed in Capivara stream and were related erosive processes in the basin. Electric conductivity, turbidity and suspended matter were higher in the rainy season and chlorophyll in the dry season. A total of 151 taxa, and a maximum abundance of 116,481 indom-2 , were observed. Chironomidae had the highest richness of taxa, followed by Trichoptera, Oligochaeta and Ephemeroptera. Chironomidae was also the most abundant group, followed by Oligochaeta and Ephemeroptera. Ephemeroptera, Plecoptera Trichoptera and Chironomus gr. decorus were the best (bio) indicators of the environmental conditions... (Complete abstract click electronic access below)

Lake sediments contain the remains of midge communities that may be used as biological proxies for inferring past environmental changes. Freshwater midges, including Chironomidae and Chaoboridae, from two alpine tarns (Pyramid Lake and Bullwinkle Lake) in the Cassiar Mountains of northern British Columbia were used to estimate Holocene palaeotemperature changes, and more specifically, to test for the presence of the Milankovitch thermal maximum, an early Holocene warm interval coinciding with peak Holocene summer solar insolation. Mean July air temperatures were reconstructed using midge-inference models developed via weighted averaging-partial least squares (WA-PLS) regression. Cold-tolerant midge taxa dominate the stratigraphies from both Pyramid and Bullwinkle Lakes; however, warm-adapted species are more common in Bullwinkle Lake. Early Holocene warming is apparent at both lakes, however it is unclear whether this is indicative of the Milankovitch thermal maximum. A decrease in temperature occurs from 8,700-7,900 cal. yr BP at Pyramid Lake, around the same time that the 8,200 cal. yr BP cooling event occurred in the northern hemisphere. During the middle Holocene, records from Pyramid Lake indicate an overall decrease in temperature, with a short period of warmer temperatures that peak at 5,100 cal. yr BP. Temperatures fluctuate little during this time at Bullwinkle Lake. A short warming phase is apparent at both lakes during the late Holocene. July temperatures are highest at 2,000 cal. yr BP (10.5°C) in Pyramid Lake and at 1,200 cal. yr BP (13°C) in Bullwinkle Lake. Thereafter, temperatures return to what they were before the warming occurred, and at Bullwinkle Lake, vary little throughout the remainder of the Holocene. / Irving K. Barber School of Arts and Sciences (Okanagan) / Earth and Environmental Sciences, Department of (Okanagan) / Graduate

Lake St. Croix is a natural impoundment located at the southern end of the St. Croix River. Land use changes since European settlement (c. 1850) have resulted in nutrient runoff, eutrophication, and periodic oxygen depletion in the hypolimnion of Lake St. Croix. Establishing sound lake management practices requires knowledge of historical conditions obtained through paleoecological studies. Remains of non-biting midges (Insecta: Diptera Chironomidae) in lake sediments have been shown to be reliable indicators of past hypolimnetic oxygen conditions. Cores from two sub-basins in the lake were collected in 2006. Midge analysis indicated that shifts in species assemblages correspond to the times of land use change. Chironomus and Procladius, which are tolerant of low oxygen levels, increased in relative abundance as land use changes adversely impacted the St. Croix River’s watershed. Volume-weighted hypolimnetic oxygen concentrations were estimated using a transfer function developed for southern Ontario. Mean post-settlement chironomid reconstructed average volume-weighted hypolimnetic oxygen values were 0.73 mg/L lower than mean pre-settlement values for sub-basin 1, near Prescott, WI and 0.45 mg/L lower for sub-basin 3, near Lakeland, MN. These results indicate that oxygen depletion has occurred in the lake since the time of European settlement, and are supported by increases in the relative abundance of eutrophic midge bioindicators and the decrease in relative abundance of bioindicators of less productive conditions since the 1850s. This study, in conjunction with other historical and paleoecological studies of Lake St. Croix, provides historical data for setting management goals and strategies for Lake St. Croix.

Crude oil commonly enters freshwater aquatic ecosystems as thin sheens forming on the water surface. Oil contains mixtures of toxic compounds called polycyclic aromatic hydrocarbons (PAHs), some of which are known to be photodynamic, increasing toxicity when combined with ultraviolet radiation. Benthic macroinvertebrate communities are commonly utilized as bioindicators, and as such rely on abundant data in literature concerning benthic macroinvertebrates' relative tolerances to a wide range of pollutants. A series of 10 plastic traps, half of which were filtered from UV radiation, were deployed in an urban pond for 27 days to determine colonization preferences of benthic macroinvertebrates to UV exposure. Results of this in situ experiment indicated that the majority of aquatic insects collected from traps inhabited the UV exposed treatment group, particularly the nonbiting midge, Chironomidae. A series of bioassays were then completed to investigate the sensitivities of a Chironomidae species to thin sheens of crude oil in the presence and absence of UV radiation. All bioassays were conducted using 10 day old Chironomus dilutus larvae cultured in the lab. The series of C. dilutus bioassays were all conducted under the same water quality parameters, temperatures, and oil sheen dosing methods, under a 16:8 photoperiod and exposed to 16 h UV per day. Five replicates (n = 20) were loaded into 350 mL glass crystallizing dishes and exposed to four treatments for 96 hours: no UV/with sheen, with UV/no sheen, both UV and oil sheen, and a control. Three assays with 175 mL water volume were completed, one with no sediment, one with silica sand, and one with fine sand. Sediment type had a significant effect on mortality (p < 0.0001), but significant effects of UV or PAHs were not found. Two more C. dilutus assays were completed with identical parameters as the latter two with sediment, except a decreased water volume of 90 mL was used to bring the sheen closer to sediment. There was a significant effect of PAHs on mortality (p = 0.0003), however, no clear trend showing PAHs driving mortality. Results showed no significant effects of UV, sediment type, or relationship between UV and PAHs. A final bioassay was completed to compare phototoxic effects of PAHs on pelagic organisms with benthic organisms. This bioassay used test species Daphnia magna, for a 48 h exposure period with five replicates (n = 10), 8 h UV exposure and 16:8 photoperiod. All individuals in the control group and UV only group exhibited 0% mortality, and with sheen/with UV treatment group resulted in 100% mortality following the 48 h exposure. The results of the D. magna exposure showed significant effects of PAHs (p < 0.0001), UV (p = 0.037), and photoinduced toxicity (p = 0.024), and were consistent with similar bioassays in the literature. This study suggests that C. dilutus are at low risk to photo-induced oil sheen toxicity.

Made available in DSpace on 2014-06-11T19:22:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-28Bitstream added on 2014-06-13T20:10:13Z : No. of bitstreams: 1 rocha_fc_me_sjrp.pdf: 876174 bytes, checksum: 186df0b1db60e6a2c675e44fa547a313 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / As plantas aquáticas são importantes componentes dos ecossistemas lóticos e lênticos. Como conseqüências de transformações ambientais, algumas podem se tornar dominantes, sendo que as plantas aquáticas do gênero Typha são bem sucedidas em brejos e alagados, podendo também ser encontradas em córregos e ribeirões. O presente estudo foi realizado com o objetivo de avaliar a influência de T. angustifolia para a ictiofauna em riachos. Foram estudados seis riachos na bacia do Alto Rio Turvo, Estado de São Paulo, desprovidos de vegetação ripária nativa, mas com abundância de T. angustifolia no hábitat interno e ripário. Por meio da análise de mapas de cobertura do solo, observou-se que T. angustifolia está amplamente distribuída nas zonas ripárias ao longo das drenagens estudadas. Os riachos com as maiores proporções de T. angustifolia nas zonas ripárias também apresentaram a menor riqueza de espécies e abundância de peixes. A baixa semelhança na composição e estrutura da ictiofauna entre os períodos sazonais, a grande quantidade de espécies tolerantes e o fato de que a maioria das espécies foi ou acessória ou acidental, sugerem uma dinâmica populacional do tipo “fonte e dreno” nos riachos estudados. Desta forma, os trechos livres de Typha atuam como “fontes”, provendo indivíduos que, por migração, podem ocasionalmente explorar os trechos com elevada abundância de T. angustifolia. Nestes trechos, que teriam o papel funcional de “drenos”, as condições ambientais são pouco apropriadas para a manutenção de uma comunidade diversa e residente de peixes. Os indivíduos dos trechos “fonte” à montante e à jusante que para ali migram se beneficiam de uma oferta relativamente constante de alimento, embora pouco variada (principalmente larvas aquáticas de Chironomidae e detritos), e abrigos (raízes de Typha). / Aquatic plants are a major component of lenthic and lotic ecosystems. As consequences of environmental changes, some species may became dominant, being that aquatic plants of the genus Typha are a well successful group of weeds in swamps and flooded areas, but also found in headwaters and large streams. This study was made with the aim to investigate the influences of T. angustifolia on the fish assemblages in streams. A total of six streams in the Upper Rio Turvo basin, São Paulo state, without riparian vegetation but with abundance of T. angustifolia in the instream and riparian habitat, were studied. By analyzing soil coverage maps, it was registered that T. angustifolia was widespread in the riparian zones along studied drainages. Streams with the largest proportions of T. angustifolia along riparian zones were also those with lowest fish species richness and abundance. Low similarity in the composition and structure of fish fauna between seasonal periods, together with a large number of tolerant species, and the fact that most species are accessory or accidental, suggest a “source and sink” population dynamic in the studied streams. Thus, free Typha stretches play as a “source” habitat, providing individuals that, by migration, may occasionally explore stretches with large abundance of T. angustifolia. In these stretches, which play a “sink” functional role, environmental conditions are often little appropriated to the maintenance of a diverse and resident fish assemblage. The migrating individuals from up and down “source” stretches are benefited by relatively constant food offer, but few diverse (mostly aquatic larvae of Chironomidae and detritus), and shelters (Typha roots).

Orientador: Marcos Gomes Nogueira / Banca: Alaide A. Fonseca Gessner / Banca: Virgínia Sanches Uieda / Resumo: Os rios de pequeno e médio porte são os ecossistemas aquáticos altamente representativos no estado de São Paulo que, tendo a maior produção econômica e maior densidade demográfica do país, sofre com a intensa degradação ambiental. A análise integrada das características da água, do sedimento e da comunidade de macroinvertebrados bentônicos e fundamental para a determinação da qualidade dos ambientes lóticos. 0 presente trabalho buscou avaliar características limnológicas gerais da água e sedimento, bem como a fauna de macroinvertebrados bentônicos dos principais rios do município de Botucatu e região (Capivara, Lavapés, Araquá e Pardo). Os estudos foram feitos em dois períodos do ano: chuvoso (março/2007) e seco (setembro/2007). A largura, profundidade, vazão e temperatura da água aumentaram no sentido jusante; a velocidade, transparência da água e oxigênio dissolvido foram maiores nos trechos à montante; a luminosidade foi total na maioria das estações de amostragem e o pH foi ácido em todos os rios estudados. As estações que sofrem maior impacto de fontes de poluição (rio Lavapés e Araquá) apresentaram os maiores valores de condutividade elétrica, material em suspensão (orgânico e inorgânico), nitrogênio total, nitrato, nitrito, amônia fósforo total, fosfato total dissolvido (orgânico e inorgânico), DBO e coliformes termotolerantes. A maior concentração de silicato foi encontrada no rio Capivara e está relacionada com os intensos processos erosivos na bacia. No período chuvoso a condutividade elétrica, turbidez, material em suspensão foram maiores, enquanto que a clorofila- a foi maior no período seco. Foram encontrados 151 táxons e abundância máxima de 116.481 ind/m2 . Chironomidae apresentou a maior riqueza, seguido... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Rivers and streams of low and medium orders are among the most important aquatic ecosystem of Sao Paulo. This State has the highest economical production and demographic density of the country. Thus, these environments are under severe degradation. Integrated analyses of water, sediment and benthic macroinvertebrates are essential in the assessment of freshwater quality. This study aimed to assess the environmental quality and structure of benthic macroinvertebrates of the main rivers and streams of Botucatu (SP) (Capivara, Lavapes, Araqua and Pardo) and adjacent region. The fieldwork was carried out in rainy (March/207) and dry (September/2007) seasons. Channel width, depth, water velocity and temperature increased towards the rivers mouth. Velocity, water transparency and dissolved oxygen were higher in the upstream sampling stations, light penetration was total in most sampling stations and pH was acid in all studied streams. The most impacted sampling stations, basically by pollution sources (Lavapés and Araquá Rivers), exhibited the highest values of electric conductivity, suspended matter (organic and inorganic), total nitrogen, nitrate, nitrite, ammonium, total dissolved phosphorus (organic and inorganic), BOD and thermotolerant coliforms. Higher silicate concentrations were observed in Capivara stream and were related erosive processes in the basin. Electric conductivity, turbidity and suspended matter were higher in the rainy season and chlorophyll in the dry season. A total of 151 taxa, and a maximum abundance of 116,481 indom-2 , were observed. Chironomidae had the highest richness of taxa, followed by Trichoptera, Oligochaeta and Ephemeroptera. Chironomidae was also the most abundant group, followed by Oligochaeta and Ephemeroptera. Ephemeroptera, Plecoptera Trichoptera and Chironomus gr. decorus were the best (bio) indicators of the environmental conditions... (Complete abstract click electronic access below) / Mestre

Orientador: Lilian Casatti / Banca: Katharina Eichbaum Esteves / Banca: Denise de Cerqueira Rossa Feres / Resumo: As plantas aquáticas são importantes componentes dos ecossistemas lóticos e lênticos. Como conseqüências de transformações ambientais, algumas podem se tornar dominantes, sendo que as plantas aquáticas do gênero Typha são bem sucedidas em brejos e alagados, podendo também ser encontradas em córregos e ribeirões. O presente estudo foi realizado com o objetivo de avaliar a influência de T. angustifolia para a ictiofauna em riachos. Foram estudados seis riachos na bacia do Alto Rio Turvo, Estado de São Paulo, desprovidos de vegetação ripária nativa, mas com abundância de T. angustifolia no hábitat interno e ripário. Por meio da análise de mapas de cobertura do solo, observou-se que T. angustifolia está amplamente distribuída nas zonas ripárias ao longo das drenagens estudadas. Os riachos com as maiores proporções de T. angustifolia nas zonas ripárias também apresentaram a menor riqueza de espécies e abundância de peixes. A baixa semelhança na composição e estrutura da ictiofauna entre os períodos sazonais, a grande quantidade de espécies tolerantes e o fato de que a maioria das espécies foi ou acessória ou acidental, sugerem uma dinâmica populacional do tipo "fonte e dreno" nos riachos estudados. Desta forma, os trechos livres de Typha atuam como "fontes", provendo indivíduos que, por migração, podem ocasionalmente explorar os trechos com elevada abundância de T. angustifolia. Nestes trechos, que teriam o papel funcional de "drenos", as condições ambientais são pouco apropriadas para a manutenção de uma comunidade diversa e residente de peixes. Os indivíduos dos trechos "fonte" à montante e à jusante que para ali migram se beneficiam de uma oferta relativamente constante de alimento, embora pouco variada (principalmente larvas aquáticas de Chironomidae e detritos), e abrigos (raízes de Typha). / Abstract: Aquatic plants are a major component of lenthic and lotic ecosystems. As consequences of environmental changes, some species may became dominant, being that aquatic plants of the genus Typha are a well successful group of weeds in swamps and flooded areas, but also found in headwaters and large streams. This study was made with the aim to investigate the influences of T. angustifolia on the fish assemblages in streams. A total of six streams in the Upper Rio Turvo basin, São Paulo state, without riparian vegetation but with abundance of T. angustifolia in the instream and riparian habitat, were studied. By analyzing soil coverage maps, it was registered that T. angustifolia was widespread in the riparian zones along studied drainages. Streams with the largest proportions of T. angustifolia along riparian zones were also those with lowest fish species richness and abundance. Low similarity in the composition and structure of fish fauna between seasonal periods, together with a large number of tolerant species, and the fact that most species are accessory or accidental, suggest a "source and sink" population dynamic in the studied streams. Thus, free Typha stretches play as a "source" habitat, providing individuals that, by migration, may occasionally explore stretches with large abundance of T. angustifolia. In these stretches, which play a "sink" functional role, environmental conditions are often little appropriated to the maintenance of a diverse and resident fish assemblage. The migrating individuals from up and down "source" stretches are benefited by relatively constant food offer, but few diverse (mostly aquatic larvae of Chironomidae and detritus), and shelters (Typha roots). / Mestre

No description available.