Photophysiology, metabolism and trophic ecology in octocorals under simulated climate change

• Grant number: 24/10584-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: August 01, 2024
• End date: July 31, 2026
• Field of knowledge: Biological Sciences - Zoology - Physiology of Recent Groups
• Principal Investigator: Samuel Coelho de Faria
• Grantee: Letícia Guerreiro Pinheiro
• Host Institution: Centro de Biologia Marinha (CEBIMAR). Universidade de São Paulo (USP). São Sebastião , SP, Brazil
• Associated research grant: 22/03105-7 - Using the phylogenetic past to predict climate impacts: ecophysiology of symbiosis and accelerated evolution to coral reef conservation, AP.PNGP.PI

Abstract

The subclass Octocorallia (Cnidaria, Anthozoa), a significant component of Brazilian reef ecosystems, contributes to reef complexity, function, and biodiversity. Brazil is notable for its high endemism of octocorals, with many shallow water species considered endemic. Climate change, primarily the increase in ocean temperatures, has led to coral bleaching and a reduction in coral cover, while studies report an increase in octocoral cover in the Atlantic and Indo-Pacific reefs following El Niño events. However, the literature lacks information on the physiological responses of octocorals in the context of global warming. It is therefore necessary to understand how different species will cope with environmental stress conditions and which will be more susceptible to global and local threats. In this context, the objective here is to characterize the physiology of Brazilian octocorals with and without photosymbiosis to understand how temperature affects symbiosis, trophic ecology, and oxidative and energetic metabolism under climate scenarios simulated for 2100. To this end, eight species of octocorals will be evaluated using biomarkers of oxidative and energetic metabolism and/or symbiosis to test the hypotheses that: (i) elevated temperatures promote oxidative stress, reduce energetic metabolism and autotrophy, and promote heterotrophic behavior; (ii) symbiotic species have lower physiological tolerance to temperature due to the increased production of reactive oxygen species by the symbionts' photosynthetic machinery; and (iii) the metabolic state under temperature effects will be reversed when thermal stress ceases. Data will be generated to understand the tolerance and susceptibility of octocorals under simulated climate scenarios, which have the potential to provide support for management and conservation plans in the face of climate change, particularly for the Brazilian octocoral fauna, given its unique environmental characteristics and notable endemism.