Impacts of Marine Heat Waves on Coastal Ecosystems in the Eastern Tropical Atlantic: Insights from the Gulf of Guinea and Grand-Béréby Marine Protected Area

This study examines the occurrence and impacts of Marine Heat Waves (MHWs) in the Eastern Tropical Atlantic, with a focus on the Gulf of Guinea. Using sea surface temperature (SST) data from OISST (1991-2020) and the PIRATA network (October 2019-March 2020), we identified an average of two MHW events per year over the past few decades. Notably, the frequency of these events has increased since 2015, with the northern coast of the Gulf of Guinea experiencing the most significant rise. We categorize the region into three key zones: the northern Gulf of Guinea, the equatorial zone, and the Congo-Gabon coastal region. Long-duration MHWs are more prevalent in the equatorial zone, while temperature anomalies exceeding 2°C are most intense along the Congo-Gabon coast. In addition, we analyze the impact of MHWs on coastal upwelling, mangroves, and coral reefs within the Grand-Béréby Marine Protected Area in Côte d'Ivoire. Our findings highlight the significant ecological and socio-economic consequences of MHWs on these vital ecosystems. We also address the causes and potential long-term effects of rising sea surface temperatures, particularly the extension of ocean heatwaves into deeper ocean layers, as noted in the 2024 Copernicus report. This study underscores the need for enhanced monitoring and predictive tools to mitigate the impacts of MHWs in the context of climate change and protect vulnerable marine ecosystems.