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ESS1-Teses

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http://hdl.handle.net/10400.1/17

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Browsing ESS1-Teses by Subject "Ambiente"

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  • Toxicity risks linked to cyanobacteria blooms in southern Portugal reservoirs
    Publication . Caetano, Sandra; Reis, Margarida P.
    Cyanobacteria massive proliferation in freshwater ecosystems has become a relevant public health concern. The main objective of this study was to assess the toxicity risks linked to the proliferation of cyanobacteria in southern Portugal reservoirs, while alerting to the need to widen and strengthen the connection between environment and human health. This work also contributes to highlight the role of phytoplankton dynamics in the development of Cyanobacteria Hazard Algal Blooms (CyanoHABs). All addressed reservoirs revealed dominance of cyanobacteria in terms of abundance, exhibiting blooms, especially during the dry season. Following a global trend, these reservoirs exhibited CyanoHABs increase, with constant presence of toxigenic species which constitutes a threat to public health and often limits water use. From the perspective of future climate change, with expected worsening of the torrential hydrologic regime, increase in CyanoHABs occurrence is expected. Biogeographical expansion of exotic toxigenic cyanobacteria has begun in these reservoirs, also presenting public health risks, since their toxins are not regularly screened. This study includes the first notification of Cylindrospermopsis raciborskii in Alqueva reservoir, in similar abundances to those already detected by other authors in Southern Portugal reservoirs. Confirming invasive toxigenic species success in these waters. Even in oligotrophic reservoirs (Beliche), cyanobacteria prevail, indicating bottom-up factors are not always as important as assumed, whereby top-down factors must be further investigated. The development of ecological indices based on phytoplankton data should allow inderect inference about potential public health risks. Given its simplicity, the dominance index of potentially toxic cyanobacteria (PTCD) may constitute an option, when calibrated through its application to more systems. This work contributes to: (i) the understanding of cyanobacteria dynamics within phytoplankton, (ii) the acknowledgement of the hazards linked to their presence and (iii) constitutes a b
    2015-07-27Doctoral thesis Open access Show more