Evaluation of bleaching of Palythoa caribaeorum colonies in regions with different degrees and types of anthropic impacts, at APAMLN (Ubatuba - SP, Brazil)

• Grant number: 21/02270-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2021
• End date: January 31, 2022
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Denis Moledo de Souza Abessa
• Grantee: Amanda Escarabichi Bueno Mariano
• Host Institution: Instituto de Biociências (IB-CLP). Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil

Abstract

Zoanthid colonies are essential for the dynamics of rocky reefs and in the structuring of benthic communities. However, it can be affected by human activities, such as chemical pollution, sedimentation, freshwater intake, tourism activities (trampling), acidification, among others. Under stress, they can expel their zooxanthellae, when they produce reactive oxygen species, leading to bleaching. Corals exposed to anthropic stressors are more susceptible to bleaching. There are little data on coral health in APAMLN, but there is a record of high bleaching rates of Mussismilia hispida in Ubatuba - SP. Environmental monitoring and knowledge of the health of ecosystems within UC are important to support decision-making. This study aims to evaluate if the zoanthid Palythoa caribaeorum responds to environmental changes caused by human activities, and to verify its possible potential as a bioindicator of environmental quality. The study sites are Praia do Lázaro, Praia do Flamengo and Ilha das Couves, located at APAMLN, in Ubatuba - SP. The species that will be studied occur widely on the rocky shores of the Southeast, and the colonies can become completely bleached or exhibit pathologies. The zoanthids coverage will be sampled from 0 to 3m deep, along 25m transects (2 in each area) in which, photos will be taken of sample squares along the entire route. Three data samples will be taken in summer, fall, and winter 2021. Water and sediment collections will be taken from each site for abiotic data analysis. The seawater temperature will be measured during the campaigns and average seawater temperature data for Ubatuba will be requested by the Oceanographic Institute of USP. For each of the selected areas, local and surrounding information will be obtained to identify potential human activities capable of affecting colonies' health and calculate the relative environmental pressure index (REPI). The bleached areas will be calculated in each square and then for each transects. The color of polyps will be analyzed through the ImageJ program (bleached percentage) and the Coral Health Chart (degree of bleaching). The comparison of each locality data and each station data will be made by t'-student test and ANOVA followed by multiple comparisons, and linear regression. The results will be organized in a matrix and the application of multivariate analyses will be made. This research will contribute to the knowledge about the P. caribaeorum colonies' health in APAMLN places and generate information on the relationship of bleaching and/or pathologies with anthropic impacts. The project hopes to be able to determine if P. caribaeorum is a good indicator organism of pollution or environmental stress, if confirmed, monitoring can be extended to other areas of APAMLN or even other marine and coastal Uc.(AU)