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Authors
Advisor(s)
Abstract(s)
As cianobactérias são organismos fotossintéticos aeróbios, sendo possivelmente os organismos procariotas fotossintéticos mais antigos que se conhecem. Têm a capacidade de prosperar em habitats terrestres, marinhos e de água doce, sendo que os habitats de água doce são aqueles em que é mais usual, quando se encontram condições favoráveis de luz, temperatura e nutrientes, de ocorrer um aumento significativo da população de cianobactérias, fenómeno designado por bloom. As cianobactérias e as toxinas por elas produzidas podem constituir um risco ambiental e de Saúde Pública quando ocorrem em quantidades elevadas e não existe um controlo e/ou monitorização do seu crescimento. O objetivo deste trabalho consistiu em avaliar a população de cianobactérias presentes em albufeiras do Alentejo, nomeadamente nas albufeiras do Enxoé e de Monte Novo, num espaço temporal de 10 anos, avaliar a potencial toxicidade associada e comparar a evolução destes parâmetros com dados provenientes de estudos anteriores (referentes ao período entre 2000-2009). Foram avaliados parâmetros físicos e químicos bem como fitoplanctónicos. Os resultados dos parâmetros físicos e químicos mostram que ambas as albufeiras se encontram eutrofizadas e que este estado de eutrofização é transversal tanto ao período de 2000-2009 como ao de 2014-2019. Em ambas as albufeiras os valores de azoto amoniacal e de nitratos aumentaram, bem como a percentagem de oxigénio dissolvido, fatores que promovem o desenvolvimento de cianobactérias. Os resultados dos parâmetros fitoplanctónicos apoiam os físicos e químicos, mostrando um domínio das cianobactérias relativamente a outros grupos fitoplanctónicos. As duas albufeiras apresentaram uma maior diversidade de cianobactérias face ao estudo anterior, aquando da presença de florescências expressivas (>2000 cel/mL). As espécies identificadas são produtoras de cianotoxinas e estão descritas como potencialmente tóxicas. Verificaram-se casos em que estas espécies apresentaram uma densidade superior a 100.000 cels/mL, fatores que em conjunto indicam risco potencial moderado a elevado para as populações expostas.
ABSTRACT - Cyanobacteria are aerobic photosynthetic organisms, possibly the oldest known photosynthetic prokaryotic organisms. They have the ability to thrive in terrestrial, marine, and freshwater habitats, and freshwater habitats are those in which it is most common when favorable conditions of light, temperature, and nutrients are found, to have a significant increase in the population of cyanobacteria, a phenomenon called bloom. Cyanobacteria and the toxins produced by them can pose an environmental and Public Health risk when they occur in high amounts and there is no control and/or monitoring of their growth. The objective of this work was to evaluate the population of cyanobacteria present in Alentejo reservoirs, namely in the Enxoé and Monte Novo reservoirs, over a period of 10 years, to evaluate the potential associated toxicity and to compare the evolution of these parameters with data from previous studies (referring to the period between 2000-2009). Physical and chemical parameters as well as phytoplanktonic parameters were evaluated. The results of the physical and chemical parameters show that both reservoirs are eutrophic and that this state of eutrophication is transversal to both the 2000-2009 and the 2014-2019 periods. In both reservoirs, the values of ammoniacal nitrogen and nitrates increased, as well as the percentage of dissolved oxygen, factors that promote the development of cyanobacteria. The results of phytoplanktonic parameters support the physical and chemical ones, showing the dominance of cyanobacteria over other phytoplanktonic groups. The two reservoirs showed a greater diversity of cyanobacteria compared to the previous study, in the presence of expressive blooms (>2000 cel/mL). The identified species are cyanotoxin producers and are described as potentially toxic. There were cases in which these species presented a density greater than 100,000 cells/mL, factors that together indicate moderate to the high potential risk for the exposed populations.
ABSTRACT - Cyanobacteria are aerobic photosynthetic organisms, possibly the oldest known photosynthetic prokaryotic organisms. They have the ability to thrive in terrestrial, marine, and freshwater habitats, and freshwater habitats are those in which it is most common when favorable conditions of light, temperature, and nutrients are found, to have a significant increase in the population of cyanobacteria, a phenomenon called bloom. Cyanobacteria and the toxins produced by them can pose an environmental and Public Health risk when they occur in high amounts and there is no control and/or monitoring of their growth. The objective of this work was to evaluate the population of cyanobacteria present in Alentejo reservoirs, namely in the Enxoé and Monte Novo reservoirs, over a period of 10 years, to evaluate the potential associated toxicity and to compare the evolution of these parameters with data from previous studies (referring to the period between 2000-2009). Physical and chemical parameters as well as phytoplanktonic parameters were evaluated. The results of the physical and chemical parameters show that both reservoirs are eutrophic and that this state of eutrophication is transversal to both the 2000-2009 and the 2014-2019 periods. In both reservoirs, the values of ammoniacal nitrogen and nitrates increased, as well as the percentage of dissolved oxygen, factors that promote the development of cyanobacteria. The results of phytoplanktonic parameters support the physical and chemical ones, showing the dominance of cyanobacteria over other phytoplanktonic groups. The two reservoirs showed a greater diversity of cyanobacteria compared to the previous study, in the presence of expressive blooms (>2000 cel/mL). The identified species are cyanotoxin producers and are described as potentially toxic. There were cases in which these species presented a density greater than 100,000 cells/mL, factors that together indicate moderate to the high potential risk for the exposed populations.
Description
Mestrado em Tecnologias Clínico-Laboratoriais
Keywords
Comunidade fitoplanctónica Cianobactétias Portugal Região do Alentejo
Citation
Babo JM. Avaliação da comunidade fitoplanctónica de albufeiras do Alentejo entre 2010 e 2019 e potencial toxicidade associada [dissertation]. Lisboa: Escola Superior de Tecnologia da Saúde de Lisboa/Instituto Politécnico de Lisboa; 2022.
Publisher
Instituto Politécnico de Lisboa, Escola Superior de Tecnologia da Saúde de Lisboa