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DATE: 12/04/2023
TIME: 10:00
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Hyphomycetes associated with plant substrates in aquatic ecosystems of Rio Grande do Norte, Brazil


biodiversity, Dikarya, aquatic fungi, microfungi, tropical region

BIG AREA: Ciências Biológicas
AREA: Botânica
SUBÁREA: Taxonomia Vegetal
SPECIALTY: Taxonomia de Criptógamos

Aquatic hyphomycetes constitute the asexual phase of ascomycetes and basidiomycetes that complete one or more phases of their life cycle in water. These fungi act in the decomposition of submerged substrates, making the dissolved organic matter more palatable and with greater nutritional value for consumption by other decomposers. In Brazil, the first records were known in the Atlantic Forest of São Paulo in 1989. In the Brazilian Northeast, records are scarce in remnants of the biome of the states of Bahia, Pernambuco and Rio Grande do Norte. The present study aimed to carry out an inventory of aquatic hyphomycetes in areas of the Atlantic Forest of Rio Grande do Norte, as well as to analyze the diversity and composition of communities of these fungi in streams and lakes in Rio Grande do Norte. An inventory of aquatic hyphomycetes previously isolated from the streams was carried out: Baldum (Georgino Avelino-RN), Boa Cica (Nísia Floresta), Catu (Canguaretama-RN), Espinho (Canguaretama-RN), Pedra (Baía Formosa-RN) and Guajú (Formosa Bay-RN). In addition, submerged substrates (leaves and branches) and water parameters were collected from the water bodies of the Pium and Jiqui streams (Parnamirim-RN), and from the Jiqui lakes (Parnamirim-RN) and Ilhota (Nísia Floresta-RN) from June 2021 to April 2022. Humid chamber and submerged incubation methodologies were applied. For the ecological analyses, the T test and the Mann-Whitney Wilcoxon test were used to compare the averages of the environmental variables between different types of ecosystems, in addition to the sampling methods, considering abundance, richness and diversity. The composition of genera in ecosystems and methodologies was analyzed using Sankey and Venn diagrams. Nested ANOVA and Kruskal-Wallis were performed to assess the difference in means between ecosystems. Nested PERMANOVA was used to compare total beta diversity (βtot), turnover (βrep) and nesting (βnes) between lakes and streams and between leaves and twigs within the two types of ecosystems. With the results of the dissertation, two chapters were written: i) Aquatic hyphomycetes associated with plant debris in freshwater ecosystems of the Atlantic Forest of Rio Grande do Norte, Brazil; and ii) Comparison of sampling methods for analyzing the replacement of fungal species in contrasting aquatic ecosystems. In the first chapter, 76 taxa were observed, distributed in 35 genera of aquatic hyphomycetes associated with plant substrates in water bodies of the Atlantic Forest of Rio Grande do Norte. Among the identified species, Flagellospora minuta is a new record for the Americas; Gyrothrix encephalarti and Triscelophorus konajensis for Brazil; Flagellospora stricta, Polylobatispora deltoidea, Pseudoxylomyces elegans and Spirosphaera carici-graminis are new records for the Brazilian Atlantic Forest; and 13 are new records for Rio Grande do Norte. While, the second chapter presented 42 taxa of aquatic hyphomycetes, distributed in 34 genera. Twenty-three taxa were found on leaves, 12 on branches and seven on both substrates. For the methodologies, 25 taxa were found in humid chamber, 14 in submerged incubation and three in both methodologies. Twenty taxa were found only in lakes, 19 only in streams and four in both environments. The environments were little variable regarding the abiotic parameters of the water bodies. The only significant difference found was between the pH values of the Ilhota and Jiqui lakes. No effects were observed on abundance, richness and diversity between ecosystems and within sample units. However, the contribution of nesting increases the variation in fungal species composition when species abundances are considered. For the submerged incubation methodology, beta diversity is highest in the twig substrate. The study demonstrated a high richness of aquatic hyphomycetes for the Atlantic Forest of Rio Grande do Norte and can subsidize Funga conservation studies in these areas. In addition, the high substitution of species between the methods reinforces the importance of the combined use of different sampling strategies for a greater and better representation of fungal communities in continental aquatic ecosystems.

Presidente - ***.390.185-** - PATRÍCIA OLIVEIRA FIUZA - UFRN
Interno - 1755051 - BRUNO TOMIO GOTO
Externa à Instituição - LOISE ARAUJO COSTA - UFPB
Notícia cadastrada em: 10/04/2023 13:00
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