Marine Heatwaves: laboratory simulations for two populations of Gracilaria caudata (Gracilariales, Rhodophyta) from the Brazilian coast

• Grant number: 23/07739-3
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): January 01, 2024
• Effective date (End): March 31, 2025
• Field of knowledge: Biological Sciences - Botany
• Principal Investigator: Estela Maria Plastino
• Grantee: Henrique Rossetti Tognonato
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Marine heatwaves are local and discrete events characterized by an increase in sea surface temperature compared to climatological averages. Marine heatwaves can lead to the collapse of coastal ecosystems, threatening their biodiversity and human activities that depend on these environments. The frequency and intensity of marine heatwaves have increased in the last century and will continue to do so due to climate change, resulting in growing attention from the scientific community. Marine macroalgae are essential components for the functioning of various marine ecosystems, supporting a wide diversity of organisms, and they are vulnerable to the effects of heatwaves. Studies have shown that geographically separated populations of the same macroalgae species tend to have differences in their thermal tolerances due to local adaptations and phenotypic plasticity. Gracilaria caudata is a species of red macroalgae of economic importance, forming physiologically and genetically distinct entities called ecotypes along its wide distribution on the Brazilian coast. In this project, we aim to evaluate the physiological performance of different life stages of G. caudata, collected from populations in São Paulo (23°S) and Ceará (3°S), subjected to the effect of simulated heatwaves in the laboratory. The objective is to identify which population is more vulnerable to these events and understand the limits of acclimation and thermal adaptation of these ecotypes. Understanding these physiological responses can be crucial for preserving the biodiversity of macroalgae on the Brazilian coast in the face of climate change.