Characterization of a phytoplankton community and assessment of ecotoxicological risk in a scenario of global warming and the influence of herbicides (Atrazine and 2,4-D)

• Grant number: 23/18072-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2024
• End date: June 30, 2025
• Field of knowledge: Biological Sciences - Botany - Plant Taxonomy
• Principal Investigator: Ciro Cesar Zanini Branco
• Grantee: André Luiz Stocco
• Host Institution: Faculdade de Ciências e Letras (FCL-ASSIS). Universidade Estadual Paulista (UNESP). Campus de Assis. Assis , SP, Brazil

Abstract

The phytoplankton communities, primarily composed of microscopic organisms, play a crucial role in aquatic ecosystems. Understanding the ecological niche of these communities is vital for comprehending interactions among organisms and their environment. Knowledge and characterization of these communities, coupled with ecotoxicological risk assessment, are essential for guiding mitigation efforts against the negative impacts of global warming and widespread herbicide use in Brazilian crops. Atrazine and 2,4-D, extensively employed herbicides in Brazil, can have adverse effects on non-target organisms, particularly due to runoff into adjacent water bodies. Global warming can change the physical and chemical conditions of lentic ecosystems, such as lakes, ponds and artificial reservoirs, affecting, for example, water temperature, nutrient availability and the action of stressors such as herbicides. Such changes can potentially harm aquatic communities in terms of their structure and dynamics. In this sense, this dissertation project aims to characterize the phytoplankton community of an artificial reservoir at UNESP/Campus Assis, SP (UNESP-FCL/Assis Reservoir) and evaluate the ecotoxicological risk on this community in a multi-stressor scenario involving concomitant exposure to a global warming projection proposed by the Intergovernmental Panel on Climate Change (IPCC) (IPCC SSP2-4.5 projection) and different concentrations of two herbicides commonly used in Brazil, 2,4-D and Atrazine. The potential effects of the multi-stressor scenario on the phytoplankton community will be evaluated based on laboratory experiments and will use as response variables information on the structure (composition, richness, abundance and diversity) and temporal dynamics (monthly variation in a sampling program throughout 12 months), in addition to photosynthetic responses based on chlorophyll a fluorescence. In general, it is expected that the results of this research project can guide predictions of the risk faced by the phytoplankton community in the face of joint exposure to herbicides and global warming and, therefore, help to subsidize environmental management measures and conservation of similar aquatic ecosystems to the studied.