The effects of multiple stressors on the photosynthetic efficiency of South Atlantic, Caribbean and Indo-Pacific reef-building corals and one calcareous hydroid

• Grant number: 22/05508-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2022
• End date: September 30, 2023
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Biological Oceanography
• Principal Investigator: Miguel Mies
• Grantee: Luiza Peres de Campos
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Coral bleaching events have been happening increasingly on a more frequent and intense basis on coral reefs worldwide due to many factors related to anthropic actions. Nevertheless, South Atlantic reefs have shown lower bleaching and mortality rates with regard to these events compared to Caribbean and Indo-Pacific. However, it has never been conducted a comparative experiment, at organism level, ascertaining possible differences in resistance and resilience between coral species from these three regions (South Atlantic, Caribbean and Indo-Pacific). Thus, in this work, it will be verified if these differences regarding three stressors: temperature, turbidity and nutrification exist. For this purpose, eight coral species (Mussismilia hispida, Siderastrea sp., Orbicella franksi, Diploria labyrinthiformis, Porites divaricata, Porites lobata, Pocillopora damicornis e Acropora millepora) and one specie of a calcareous hydroid (Millepora alcicornis), three of each one of these regions, will be subjected to the three mentioned stressors, separately, and it will be analyzed the loss of photosynthetic efficiency (by using PAM - Pulse Amplitude Modulated - Fluorometer), symbionts (by using Coral Watch colour reference card and symbionts count), and chlorophyll-a (quantification of tissue chlorophyll-a concentration). Therefore, less reduction in photosynthetic parameters is expected in the case of South Atlantic corals and the calcareous hydroid in relation to the corals from the other regions.