Advanced search
Start date
Betweenand

Taxonomy and ecology of Achnanthidium (Bacillariophyceae) in the State of São Paulo, Brazil

Grant number: 17/04806-0
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): August 01, 2017
Effective date (End): October 31, 2019
Field of knowledge:Biological Sciences - Botany
Cooperation agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
Principal Investigator:Denise de Campos Bicudo
Grantee:Lívia Franco da Costa
Home Institution: Instituto de Botânica. Secretaria do Meio Ambiente (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Achnanthidium Kützing is considered a monoraphid diatom genus due to its heterovalvar frustule with one raphid and other araphid valve; also, is characterized by the linear, lanceolate or elliptical valves, with girdle view forming a deep V. In São Paulo State is estimated that around 22 species/varieties of the genus are known. However, most of the information has not been published and are devoid of scanning electron microscopy (SEM) images, essential for the better knowledge of taxa. Thus, many species require taxonomic revision. Still, ecological information on the distribution of Achnanthidium species in the State of São Paulo and the country are practically inexistent. In this way, this project aims to broaden and deepen the taxonomic and ecological knowledge of Achnanthidium species based on detailed study of populations found in different freshwater environments in the State of São Paulo. The study material includes 356 permanent slides of diatoms from two major projects of FAPESP (Biota - SP and Acquased - five river basins), covering a broad gradient of trophic states, different habitats (metaphyton, plankton, periphyton and surface sediment), seasons (summer and winter) and depths (deep and shallow sites). The taxonomic deepening will be made from the detailed analysis of the populations found in each environment and habitat in light and scanning electron microscopy, as well as the taxonomic revision of citations of these taxa in the framework of the São Paulo State. The delimitation of the population will take into account the circumscription of type materials in international herbaria and protologues available in literature. The ecological preferences of the species/varieties will be analyzed from the association of taxa quantitative distribution (relative abundance) with limnological variables (physical and chemical) available in AcquaSed project database. This proposal brings pioneering contribution to tropical regions by combining floristic and ecological approaches. It aims to solve the taxonomic problems within the genus in southeastern Brazil and to provide more consistent basis to the best knowledge of tropical populations and their use in water quality assessment. (AU)