Effects of Temperature on Heterotrophy and Energy Metabolism in Scleractinian Corals

• Grant number: 24/10586-7
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2024
• End date: August 31, 2026
• Field of knowledge: Biological Sciences - Zoology - Physiology of Recent Groups
• Principal Investigator: Samuel Coelho de Faria
• Grantee: Mariana Magnani Avelar Batista
• 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

Coral reefs are ecosystems that encompass broad biodiversity. The symbiosis established between symbiotic corals and dinoflagellates of the Symbiodiniaceae family brings significant benefits to these animals, especially in aerobic respiration and photosynthesis. However, there are also asymbiotic corals that do not possess such mutualistic relationships. From this perspective, this project aims to explore the energy metabolism and heterotrophy in these organisms, to test: (i) that high temperatures increase metabolic rates, promote heterotrophic capacity, and trigger bleaching, in contrast to low temperatures; (ii) the existence of a trade-off between the kinetics of aerobic and anaerobic metabolism at high temperatures; and (iii) that asymbiotic corals exhibit higher metabolic rates and greater heterotrophic capacities than photosymbiotic corals, both healthy and bleached. To test these hypotheses, the species Mussismilia hispida and Madracis decactis - symbiotic - and Astrangia rathbuni and Phyllangia americana - asymbiotic - will be collected (N = 7 per species) from the Alcatrazes archipelago, acclimated, and exposed to low and high temperatures, also simulating a global warming scenario. These corals will have their metabolic and/or photosynthetic rates evaluated, as well as subsequent biochemical analyses of lactate content, ATP, lactate dehydrogenase (LDH) and citrate synthase (CS) activity, and lipid markers of auto and heterotrophy. The findings will provide support for management plans, considering trophic and physiological aspects as sensitivity markers, as well as for broad scientific dissemination regarding the impacts of climate change on Brazilian coral reefs.