Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Brésil → 2021 → Phytoplankton metagenomic diversity and social risk of cyanobacterial blooms in Brazilian semiarid reservoirs : mediation of research and teaching for scientific literacy

Universidade Federal do Rio Grande do Norte (UFRN) 2021

Phytoplankton metagenomic diversity and social risk of cyanobacterial blooms in Brazilian semiarid reservoirs : mediation of research and teaching for scientific literacy

Fonseca, Aleson da Silva

Titre : Phytoplankton metagenomic diversity and social risk of cyanobacterial blooms in Brazilian semiarid reservoirs : mediation of research and teaching for scientific literacy

Auteur : Fonseca, Aleson da Silva

Université de soutenance : Universidade Federal do Rio Grande do Norte (UFRN)

Grade : Mestrado em Desenvolvimento e Meio Ambiente 2021

Résumé
The present study was based on four objectives, each corresponding to a chapter : 1) describe and compare the metagenomic diversity of the phytoplankton community, with emphasis on cyanobacteria, with the diversity obtained by the traditional method by optical microscopy ; 2) explain how the social formulation of environmental risks tied to potentially toxic algal blooms occurred, in reservoirs in the Piancó-Piranhas-Açu Hydrographic Basin ; 3) To validate the Instrument for Planning and Didactic Evaluation of Socioscientific Issues (IPADQSC) ; 4) To evaluate how a teacher training course, about QSC related to the water theme, contributes to the understanding and application of these concepts, in the construction of teaching sequences in the perspective of scientific literacy and environmental sustainability. Total DNA was extracted in water samples from Boqueirão de Parelhas and Passagem das Traíras reservoirs, and the genetic material was sequenced and analyzed with the help of the MG-RAST tool. The analysis of phytoplankton composition by metagenomics revealed 238 species, distributed in 13 groups, with cyanobacteria abundance above 90%. Comparing the two identification techniques, a higher phytoplankton diversity was found when the metagenomic identification technique was used, especially for the picoplanktonic species, to the detriment of the traditional optical microscopy identification. The diversity of filamentous cyanobacteria species, and potentially producers of cyanotoxins, represent the risk of instensification of the blooms in periods of extreme drought. The literature review, with a time frame between 1996 and 2020, detected the following social and environmental risks linked to eutrophication : contamination of water by cyanotoxins, ecological changes in the aquatic community, changes in the limnological patterns of water bodies, and damage to human health due to the use of contaminated water. The IPADQSC was designed according to the theoretical assumptions of the QSC and investigative teaching approaches, was validated with questionnaires applied to elementary school science and biology teachers, some with master’s level in science teaching and university professors. It was found during validation that seven of the 29 criteria were below the percentage of agreement, which required adaptation to make the instrument understandable. During the training course, held for 107 teachers in initial and continuing education, 21 teaching sequences were developed on the water theme using the QSC approach by means of the IPADQSC instrument. It was evident that the teachers understood the fundamental concepts of the QSC approach and scientific literacy, from indicators of scientific literacy, present in the sequences produced. It is recommended the expansion of pedagogical training to mitigate the formative weaknesses and contribute to overcoming the challenges that prevent the application of QSC in teaching practice.

Présentation

Version intégrale (12,2 Mb)

Page publiée le 19 décembre 2021