Banca de DEFESA: CLARA DANTAS NAVARRO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : CLARA DANTAS NAVARRO
DATA : 25/06/2019
HORA: 09:00
LOCAL: Didático I - Decol
TÍTULO:

Effects of application of polialuminium chloride (PAC) and benthivorous fish removal on benthic macroinvertebrates assemblages of a shallow eutrophic lake

PALAVRAS-CHAVES:

floculation, sedimentation, phosphorus imobilization, biomanipulation, bioturbation, benthos)

 

PÁGINAS: 25
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:

The application of aluminum salts and the removal of benthivorous fish are two techniques of water quality management of eutrophic lakes that tend to reduce the internal contribution of phosphorus from the sediment to the water column and to mitigate the effects of eutrophication. However, the isolated and combined effects of these two management techniques on the structure and dynamics of aquatic communities are poorly understood. The application of aluminum polychloride (PAC) increases the flow of organic matter from the water column to the sediment, increasing the availability of detritus to benthic invertebrates, while the removal of benthic fish reduces competition and / or predation pressure on themselves. Therefore, the increased availability of detritus should have a stronger positive effect on benthic macroinvertebrates in the absence than in the presence of detritus-eating benthivorous fish and therefore we should note a synergistic effect of the two techniques on the density and diversity of these organisms. To test this hypothesis, a field experiment with a 2 x 2 factorial design was carried out, combining the application or not of PAC with the presence and absence of the benthivorous fish Prochilodus brevis, a very common and abundant detritus species in the Brazilian semiarid reservoirs . The experiment was carried out in 20 mesocosms of 6 m 3 inserted in a tropical semiarid lake and the 4 treatments were randomly allocated in the mesocosms. Water and sediment samples were collected in each mesocosm at the beginning, middle and end of the experiment, which lasted 8 weeks. The benthic macroinvertebrates were identified and quantified in each sample and the density data of these organisms were treated with a two-way ANOVA. The techniques of water quality management and the interaction between them did not present effects on the benthic macroinvertebrates. Therefore, the results refuted the hypothesis of research, and suggest that the high availability of organic matter, typical of eutrophic environments, determines the lack of effect of the two techniques on benthic macroinvertebrates assemblages.

MEMBROS DA BANCA:
Presidente - 1362202 - JOSE LUIZ DE ATTAYDE
Externo à Instituição - ROSEMBERG FERNANDES DE MENEZES - UFPB
Interna - 1764855 - VANESSA BECKER