Spring algal blooms in Alexandria coastal area (Egypt) impacted by anthropogenic forcing: Potential role of habitat alteration

The Alexandria coastal area is presently experiencing two main problems of increasing intensity and concern: eutrophication and exacerbating coastline erosion. Here, we describe the spring discolored massive algal blooms in Alexandria coastal waters during 2021. These blooms were detected at two sites of highly dynamic and rapidly evolving systems with different characteristics on each site regarding abundances of the different causative species, biomass accumulation, and prevailing environmental variables mainly supported by daily discharged water input. The blooms can be considered one facet of the complex hydrographic ecosystem's responses to anthropogenic forcing.  The study offers evidence of the potential role of newly created sheltered artificial microhabitats that favor water confinement exacerbated impacts on the water quality, fostering colonization of the bloom causative species, and biomass accumulation. Further ecological studies on the effect of coastal zone modification are required before its deployment, particularly in intensive urbanization areas.