Assessing Environmental Impacts on Coral Reef Ecosystems under Climate and Anthropogenic Pressures based on GEE workflow in the Northwestern Gulf of Suez, Egypt

Abstract

Coral reef ecosystems, often described as the “rainforests of the sea,” play a vital role in maintaining marine biodiversity and coastal protection but are increasingly threatened by climate change and human-induced pressures. This study integrates Remote Sensing (RS) and Geographic Information Systems (GIS) within the Google Earth Engine (GEE) cloud-computing framework to assess the degradation of coral reefs along the western coast of the Gulf of Suez, Egypt. A robust, reproducible methodology was developed to analyze a 33-year time series (1986–2019) of Landsat and Sentinel-2 imagery. Key environmental stressors, including sea surface temperature (SST), chlorophyll-a concentration, and water turbidity, were quantified using validated algorithms. Coral reef extent was mapped using a supervised Random Forest classification, achieving an overall accuracy of 91.2%. Results revealed a net loss of 1.15 km² of coral reef cover over the study period, decreasing from 57.15 km² in 1986 to 55.99 km² in 2019, with an estimated uncertainty of ±2.8 km². Spatial analysis showed distinct regional variations: the most pronounced losses occurred in Zone 2 (Ras El Adabia–Ain Sokhna Port; –4.89 km²) and Zone 4 (Ras Abu Darge–Ras El Zaafrana; –4.37 km²), mainly due to maritime operations, port expansion, and coastal urbanization. Conversely, Zone 7 (Ras Bakar–Al-Ghardaqa) exhibited a notable increase of +7.4 km², likely linked to favorable hydrodynamic conditions and limited anthropogenic disturbance. These findings demonstrate how localized human activities and natural processes jointly shape reef dynamics. The study underscores the critical importance of integrating validated geospatial technologies into early warning systems, conservation planning, and adaptive management strategies to enhance the long-term sustainability of coral reef ecosystems amid accelerating global environmental change.