Banca de QUALIFICAÇÃO: IRMA CARVALHO E SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : IRMA CARVALHO E SILVA
DATE: 30/01/2024
TIME: 08:30
LOCAL: Google meet - https://meet.google.com/eop-qqpi-ryt
TITLE:

Epiphyton-macrophyte interactions in a changing world

KEY WORDS:

Grazing; Climate change; Allelopathy.

PAGES: 100
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Epiphytic algae and submerged macrophytes are directly associated. Therefore, in a climate change scenario, local interactions between both communities may be intensified by competition processes. This could reflect changes in the patterns of diversity and functioning of aquatic ecosystems. The thesis is structured into three chapters that experimentally evaluate ecological issues related to epiphyte-submerged macrophyte interactions. The first chapter presents a study on the impact of temperature and nutrients on the interaction between epiphyton and the macrophyte Egeria densa Planch. The second chapter focuses on the influence of these factors and the type of substrate on the composition, taxonomic and functional richness, and uniformity of the epiphytic community. A laboratory experiment was conducted with three treatments, Relation (Epiphyton + Mimic, Macrophyte + Epiphyton inoculum, and Macrophyte without Epiphyton inoculum), Nutrients (High and low concentration), Temperature (27°C and 30°C) with 4 replicates for 63 days. The experiment showed that higher temperatures decreased the biomass of the macrophyte and increased the number of lateral sprouts. However, the sprouts were smaller in size, and biomass compared to the current temperature treatment. The presence of epiphyton also had a significant impact, reducing the length of the lateral sprouts. The total richness of epiphyton varies depending on the substrate, with greater richness found in the natural substrate. The interaction of temperature, nutrients, and substrate type affected the total density, resulting in differences over time. In the second chapter, we expect a variation in the epiphytic composition influenced by the interaction of three factors. Cyanobacteria will be more abundant when associated with artificial substrate under high temperature and nutrient concentration conditions. However, we expect that the epiphytic community will exhibit greater richness and functional uniformity in scenarios with lower nutrient concentrations, current temperatures, and association with macrophytes. Conversely, this trend will be reversed in scenarios of warming, artificial substrate, and high nutrient concentration. In the third chapter, we carried out field experiments to test the effects of allelopathy and herbivory on epiphytic biomass. The study considered the type of substrate, as well as the surface and total extracts of E. dense in the control of epiphyton biomass. The results showed a significant reduction in epiphyton biomass in the natural substrate and associated with the lipid-soluble total extract of E. dense, with herbivory playing a significant role in controlling the increase of this biomass. A thorough understanding of the relationships between present and future scenarios is crucial for establishing restoration measures that promote the resilience and conservation of aquatic ecosystems. The maintenance of ecosystem services depends directly on these interactions. Therefore, it is essential to have a clear understanding of these processes to guide effective management and conservation strategies. The thesis emphasizes the significance of laboratory and field research in understanding and conserving aquatic ecosystems in the face of environmental change.

COMMITTEE MEMBERS:
Externa à Instituição - DANIELLE KATHARINE PETSCH
Presidente - 2412921 - JULIANA DEO DIAS
Interna - 1764855 - VANESSA BECKER