Banca de DEFESA: WILDNA FERNANDES DO NASCIMENTO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : WILDNA FERNANDES DO NASCIMENTO
DATE: 24/04/2023
TIME: 09:00
LOCAL: Híbrido: DOL e on line
TITLE:

Mass coral bleaching in shallow reefs of Northeast Brazil following a major heatwave

KEY WORDS:

Climate change; Thermal stress; Resistance; Coral resilience

PAGES: 31
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Marine heat waves are becoming more frequent and intense due to global climate change, and are considered one of the major causes of reef degradation. Coral reefs in the Southwest Atlantic have experienced fewer heat wave events compared to the Indo-Pacific and Caribbean, but this scenario has changed in the last decade as the region has been hit by some bleaching events. In 2020, the northeast Brazilian was affected by one of the biggest heat waves in recent years, causing bleaching event never seen before in the region reaching 16.86°C-weeks, the highest value since records began in 1985. health of corals from December 2019 to January 2021, in the reefs of Rio do Fogo - RN. Our goal is to understand whether the impacts caused by the heat wave vary between coral species and are influenced by morphological attributes such as colony size. We assessed coral health using the Coral Watch Coral Health Chart through photo-squares along 5 transects. We evaluated the health of the stony corals Agaricia agaricites, Favia gravida, Porites astreoides, Siderastrea stellata and the zoanthids Palythoa caribaeorum, Palythoa grandiflora, Palythoa variabilis and Zoanthus sociatus. We observed that the stony corals showed a high level of bleaching when the heat wave was at its highest (April and May) and the species P. astreoides and S. stellata were able to recover their healthy color in about two months. The opposite was observed for A. agaricites and F. gravida, which presented coverage losses of 100% and 90% respectively. In the case of zoanthids, the species remained stable. We observed that small colonies (< 5cm²) of S. stellata (dominant coral) showed greater sensitivity to the heat event, bleaching before larger colonies. In the period when the heat wave was most severe, more than 85% of the number of colonies of all classes showed signs of bleaching, with a decline in this value after the fall in Degree Heating Weeks (DHW). Thus, coral species should remain stable after bleaching events, although less abundant species have not recovered, which can cause loss of coral diversity, threatening the coral fauna that is highly endemic in these areas.

COMMITTEE MEMBERS:
Externa à Instituição - AMANA GUEDES GARRIDO
Presidente - 2319234 - GUILHERME ORTIGARA LONGO
Externo à Instituição - MIGUEL MIES