Banca de QUALIFICAÇÃO: FERNANDA MONICELLI CÂMARA BRITO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : FERNANDA MONICELLI CÂMARA BRITO
DATE: 31/05/2023
TIME: 14:00
LOCAL: LARHISA - sala de aula
TITLE:

Effects of the geoengineering technique on the control of eutrophication in planktonic organisms

KEY WORDS:

cyanobacteria; phytoplankton, Floc and sink; Floc and lock; restoration; zooplankton.

PAGES: 116
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

There are several techniques to control eutrophication, physical and chemical techniques have been widely used, however there are few studies on the effects of these techniques on phytoplankton and zooplankton. In view of this, the general objective of this thesis is to analyze the responses of the planktonic community to the geoengineering technique to control the eutrophication of water sources in the semi-arid tropical region. The first chapter aimed to carry out a scientometric analysis of the literature to observe the effect of chemical and physical techniques to control eutrophication in planktonic organisms in eutrophic environments, evaluating the bibliometric production and determining gaps in knowledge. The results showed that these techniques have been extensively studied and there has been more interest in them over the years. Despite this, few studies focus on the effects of techniques on plankton. The effects of the technique on other phytoplanktonic groups, in addition to cyanobacteria and on zooplankton are little discussed and it is still unclear how these techniques act on theseorganisms, being one of the gaps found in the first chapter. In addition, studies that observe the effects over time, showing the succession of the planktonic community and in mesocosms are a minority and also need to be analyzed. Overall, all chemical techniques removed cyanobacterial biomass or biovolume. Unlike physical techniques that had conflicting results, with inconclusive results. The few studies after application of the technique show positive effects on phytoplankton diversity after Floc and sink and an increase in richness after Floc and lock and aeration. All techniques negatively affected zooplankton, decreasing the biomass, survival or abundance of these organisms. Therefore, some of these gaps will be answered in the following chapters, focused on the geoengineering technique, chemical geoengineering technique has been gaining prominence in the last decade. The technique aims to manipulate the biogeochemical cycle of P, removing particulate P (algal biomass) by sedimentation, and dissolved P from water by adsorption and sediment capping. The technique uses a combination of coagulant and clay (natural or modified) for sedimentation. Chapter two aimed to analyze the effects on biomass and phytoplanktonic composition, when applying the Floc and Sink (F&S) mitigation technique, in eutrophic waters from reservoirs in the semi-arid tropical region. The technique was able to sediment algal biomass with the addition of coagulant plus ballast (PAC+Planosso; PAC+Beige Limestone and PAC+White Limestone) and observed its effects on the functional groups. The groups with sedimentation resistance mechanism (MBFG VIII) are unable to sediment with the isolated use of coagulants, especially due to the presence of aerotopes. The MBFG VII group, due to the presence of the mucilage sheath, did not sediment, unlike the MBFG IV group, which, due to the lack of specialized characteristics, sedimented with only the use of the coagulant. The MBFG V group in contact only with the PAC increased and the MBFG VI group, despite its silica wall, did not show statistical differences in group removal. Chlorophytes and cryptophytes (MBFG groups IV and V) are considered high quality foods, therefore, it is important to observe the palatability and nutritional value of phytoplankton species, after the Floc and Sink test, as it directly influences the flow of energy to the other trophic levels. Therefore, natural ballasts are capable of sedimenting algal biomass combined with coagulants and can be used as an alternative to commercial products with high values. The third chapter will evaluate the effects of the Floc and lock restoration technique on the biodiversity of planktonic communities in the medium term. It is expected that with the reduction of P availability, due to the treatments with adsorbents in the capping of the sediment, there will be a decrease in the algal biomass, sedimenting in the first days of the experiment. We believe that biomass will remain low throughout the experiment due to P limitation, with a decrease in cyanobacteria and a change in the compositional dominance of taxonomic groups. With regard to zooplankton, it is expected that initially there will be a decrease in organisms, decreasing the total biomass, especially in rotifers and cladocerans due to their form of feeding. It is generally believed that planktonic communities will decrease in richness and diversity in the first few days, but over time they will recover becoming more diverse than they were initially, but with lower biomass. Finally, the fourth chapter aims to evaluate the effects of the Floc and Sink restoration technique on the survival and immobilization of different species of zooplankton. Notodiaptomus sp. and Diaphanosoma sp. We hope that the application of the technique will promote a decrease in survival and an increase in zooplankton immobilization. The species of Diaphanosoma sp., as a filter feeder, will be more affected than the copepod Notodiaptomus sp. Therefore, we believe that EC50 and LC50 values will be found at higher doses for Notodiaptomus sp.. 

COMMITTEE MEMBERS:
Externo à Instituição - JANDESON BRASIL DIAS
Interna - 2412921 - JULIANA DEO DIAS
Interno - 1103317 - KEMAL ALI GER
Interna - 1345773 - RENATA DE FÁTIMA PANOSSO
Presidente - 1764855 - VANESSA BECKER