title: The Gulf of Aden Intermediate Water Intrusion Regulates the Southern Red Sea Summer Phytoplankton Blooms.
abstract: Knowledge on large-scale biological processes in the southern Red Sea is relatively limited, primarily due to the scarce in situ, and satellite-derived chlorophyll-a (Chl-a) datasets. During summer, adverse atmospheric conditions in the southern Red Sea (haze and clouds) have long severely limited the retrieval of satellite ocean colour observations. Recently, a new merged ocean colour product developed by the European Space Agency (ESA)-the Ocean Color Climate Change Initiative (OC-CCI)-has substantially improved the southern Red Sea coverage of Chl-a, allowing the discovery of unexpected intense summer blooms. Here we provide the first detailed description of their spatiotemporal distribution and report the mechanisms regulating them. During summer, the monsoon-driven wind reversal modifies the circulation dynamics at the Bab-el-Mandeb strait, leading to a subsurface influx of colder, fresher, nutrient-rich water from the Indian Ocean. Using satellite observations, model simulation outputs, and in situ datasets, we track the pathway of this intrusion into the extensive shallow areas and coral reef complexes along the basin's shores. We also provide statistical evidence that the subsurface intrusion plays a key role in the development of the southern Red Sea phytoplankton blooms.
authors.affiliation: Computer, Electrical and Mathematical Sciences & Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
authors.forename: Denis
authors.initials: D
authors.lastname: Dreano
authors.affiliation: Remote Sensing Group, Plymouth Marine Laboratory, Plymouth, United Kingdom.|National Centre for Earth Observation, Plymouth Marine Laboratory, Plymouth, United Kingdom.
authors.forename: Dionysios E
authors.initials: DE
authors.lastname: Raitsos
authors.affiliation: Biological and Environmental Science & Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
authors.forename: John
authors.initials: J
authors.lastname: Gittings
authors.affiliation: Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
authors.forename: George
authors.initials: G
authors.lastname: Krokos
authors.affiliation: Computer, Electrical and Mathematical Sciences & Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.|Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Hoteit
mesh_terms: D019156:Indian Ocean; D010839:Phytoplankton / Q000254:growth & development*; D012621:Seasons; D012623:Seawater / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D015006:Yemen
chemical_list: D014867:Water