Banca de DEFESA: CAIO VITOR MATOS MOREIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : CAIO VITOR MATOS MOREIRA
DATE: 29/07/2022
TIME: 14:30
LOCAL: videoconefência
TITLE:

IMPACTS OF EXTREME CLIMATE EVENTS ON THE WATER QUALITY OF CONTINENTAL WATER BODIES

KEY WORDS:

Climate change, precipitation, droughts, storms, eutrophication, scientometrics, water quality, monitoring, semi-arid

PAGES: 56
BIG AREA: Engenharias
AREA: Engenharia Sanitária
SUBÁREA: Recursos Hídricos
SUMMARY:

Extreme weather events (EWEs) related to precipitation, such as drought and heavy rains, have great potential to change the water quality of continental water bodies, due to climate change these events have become more frequent. Therefore, these phenomena are important threats to these environments that play different roles in our society. Understanding how these events impact continental water bodies on a temporal and spatial scale is an important tool for managing and mitigating these future impacts. Therefore, the objective of this study is to find temporal and spatial patterns of these effects and understand how local-scale particularities can amplify the impacts of extreme weather events. For this, we developed in our first chapter a systematic review using scientometrics, which is the branch of science that proposes to study aspects of scientific production, in this way it is possible to understand trends and gaps in an area of science. In the scientometric analysis, we used scientific studies published in the Web of Science and Scopus databases as a source of information, we used the expression “extreme event” (i.e. representing extreme weather events) associated with one of the following expressions: AND “water quality”, OR “ freshwater” OR “limnol*” in the search engines of these two databases in order to obtain publications related to the topic as a return. We removed the following information from each article: type of study event, climate zone of the study area, approach, ecosystem studied, type of parameter studied, biological communities (when there is a biological study), impact on the main parameter and impact on water quality . 281 publications were used to analyze the temporal production of studies and for the remaining analysis we removed the review articles, resulting in 254 articles. We observed an increase in publications on the subject from 2014 onwards, we found that the temperate climate zone is the one that most produces these articles, rivers are the most studied ecosystems and the vast majority of these studies report negative impacts on the water quality of these environments. In addition, these events cause relevant ecological changes due to the physicochemical changes superimposed on these water bodies. We understand that this increase in the number of studies was caused by the publication of reports from international bodies on climate change and ECEs, the regional pattern of publications is more related to the general scientific production of these locations than a greater occurrence of EWEs in these regions. EWEs are able to introduce and increase concentrations of solids, nutrients and various pollutants. These events still intensify the eutrophication process and the intensity and duration of these impacts are controlled by the characteristics of the watershed and antecedent conditions of these water bodies. In our second chapter, we used limnological monitoring data from 10 years (2011-2021) to analyze the impact of water level fluctuation during a prolonged drought under a Brazilian semi-arid reservoir, where at the beginning of the drought there was a high volume of water and had its depth decreasing until it dried completely, at the end of the monitoring period we still observed the re-inundation of the water body. We verified if the dry period intensified the eutrophication of this reservoir. We used cluster analysis to separate the monitoring months into clusters and the Kruskall-Wallis analysis and Principal Component Analysis (PCA) to analyze differences between periods and environmental variables. Our cluster analysis divided into three periods characterized by their maximum depths (Zmax) as: intermediate (I), dry period (II) and flood period (III). The variables: suspended solids (fixed and volatile), turbidity, electrical conductivity, orthophosphate, total phosphorus and chlorophyll-a showed lower values during the flood period (III), while the Secchi transparency and the dissolved oxygen concentrations observed in the periods of lower depths (I and II) were lower when compared to period III. Thus, we were able to verify the degradation suffered by the reservoir during the prolonged drought and that during the periods of lower water levels we had degradation of water quality and aggravation of eutrophication. We conclude from this study that precipitation ECEs negatively impact continental water bodies and these impacts alter the physical, chemical and biological dynamics of these ecosystems. In addition, environmental conditions of the drainage basin in which these water bodies are inserted are important factors for controlling this impact. Studies like this provide us with subsidies for decision-making in the management and recovery of water bodies and become even more relevant when we evaluate the predictions of greater occurrence due to the changes in water supply.

COMMITTEE MEMBERS:
Presidente - 1764855 - VANESSA BECKER
Externa ao Programa - 2412921 - JULIANA DEO DIAS - UFRNExterno à Instituição - JOSÉ NEUCIANO PINHEIRO DE OLIVEIRA - IFCE
Externa à Instituição - MARIANA RODRIGUES AMARAL DA COSTA - UFRN