Banca de QUALIFICAÇÃO: LAIANE LANE LUCENA DE MEDEIROS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : LAIANE LANE LUCENA DE MEDEIROS
DATE: 02/12/2021
TIME: 08:00
LOCAL: Videoconferência online
TITLE:

Influence of macroalgae on the trophic web of coastal environments impacted by fisheries

KEY WORDS:

Eutrophication, artisanal fisheries, EwE, trophic structure, ecosystem development, keystone species

PAGES: 70
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Coastal environments are being frequently degraded as a result of anthropogenic impacts. Macroalgal blooms are a consequence of eutrophication of water bodies through bottom-up regulation, which can favor herbivorous, detritivores and filter-feeding organisms and increase gross primary productivity and respiration of ecosystems. Similarly, fisheries overexploitation can act in top-down regulation, favoring macroalgal blooms via declines in top predatory fish. In order to understand the complexity of trophic webs of coastal ecosystems impacted by macroalgae and fishing activity, we used the software Ecopath with Ecosim. For this, two coastal environments exploited by artisanal fishermen were evaluated and compared: Baía Formosa (BF) and Porto do Mangue (PM) (environment influenced by macroalgae blooms), both in Rio Grande do Norte state, northeastern Brazil. The high concentration of nutrients added to the semi-arid conditions of PM favored a higher biomass of Primary Producers (Macroalgae and Phytoplankton) and Fishes in this ecosystem. BF showed a higher biomass of invertebrates, favored by the low algal biomass and finer sediment of this ecosystem, composed of silt and clay, and enriched in organic matter. Such structural characteristics of PM resulted in high Net Primary Production and flow diagram based on bottom-up regulation. However, macroalgae did not show significant importance in the trophic web, since much of its biomass was transformed into detritus and exported to adjacent ecosystems, which characterized it as an immature ecosystem. The opposite was found in BF, because this ecosystem was considered mature, with a high flow of consumption and respiration, and also a high representation of all trophic levels in its flow diagram. Fishing, on the other hand, did not favor macroalgae blooms, but differentially affected the other compartments between the ecosystems. In BF, the capture specialized in top predators favored fish of intermediate trophic levels. In PM, fishing had a detrimental effect along the web because the catch was generalized, negatively impacting the various trophic levels. Therefore, eutrophication and fishing activity in PM generated greater stress for the species that make up the trophic web of this ecosystem, hindering the evolution towards a more stable and mature state of ecological succession.

BANKING MEMBERS:
Externo à Instituição - ALEX SOUZA LIRA - UFDPar
Externo à Instituição - CARLOS EDUARDO ROCHA DUARTE ALENCAR - URCA
Externa à Instituição - FLAVIA LUCENA FRÉDOU
Presidente - 1545394 - FULVIO AURELIO DE MORAIS FREIRE
Externa à Instituição - Maria Alice Leite Lima