Influences of Physical and Biogeochemical Variability of the Central Red Sea During Winter

Abstract

The Red Sea is a long, narrow basin spanning a distance of nearly 2,000 km from the strait of Bab al Mandab in the south to the southern tip of the Sinai peninsula in the north. Surrounded by hot deserts, its primary linkage to the global ocean is through the constricted strait of Bab el Mandeb, connecting it to the Arabian Sea through the Gulf of Aden. The Red Sea is characterized by negligible freshwater input from rainfall and terrestrial runoff, high temperatures and high salinity due to solar heating, and significant evaporation rates (Berumen et al., 2019; Smeed, 1997; Sofianos, 2002) and is considered to be a predominantly oligotrophic sea (Edwards & Head, 1987; Grasshoff, 1969). Besides, the Red Sea contains one of the most diverse marine ecosystems in the world with substantial economic and environmental impacts primarily due to its coral

Regionalization of the Red Sea Based on Phytoplankton Phenology: A Satellite Analysis

“…Moreover, the bio‐regions were distributed along a latitudinal gradient with, sometimes, the coexistence of several bio‐regions at the same latitude (Figure 1). Such spatial distribution suggests that phytoplankton dynamics might be related to the basin circulation dynamic and/or the availability in nutrients (Eladawy et al., 2017; Gittings et al., 2018; Papadopoulos et al., 2013, 2015; Racault et al., 2015; Raitsos et al., 2013; Zarokanellos and Jones, 2021). Moreover, the phytoplankton phenology (i.e., timing and intensity of phytoplankton bloom) was significantly different between these bio‐regions (Figure 2).…”

“…(2018) showed that the position and the intensity of this convergence zone (18°–25°N) vary inter‐annually due to the ENSO influence. Furthermore, note that the observed winter bloom in this region could also result from vertical mixing that dispersed phytoplankton from the deep CHL maximum (Zarokanellos & Jones, 2021).…”

“…The collision of the northwest and southeast winds occurs around 18°-25°N (Figures S3_1, S3_2 and S3_3 in Supporting Information S1, Dasari et al, 2018;Langodan et al, 2014;Morcos, 1970) and can lead to a convergence zone where nutrients are supplied within the surface layer favoring the initiation of the phytoplankton bloom observed in November in the Bio-region 4 (Figure 1). Recently, Zarokanellos and Jones (2021) showed that mixing events dispersed phytoplankton from the deep CHL maximum (DCM) increasing near-surface CHL in this region. This suggests that the Bio-region 4 could simply correspond to the redistribution of the phytoplankton biomass vertically in response to mixing events.…”

Frontal Dynamics in the Alboran Sea: 1. Coherent 3D Pathways at the Almeria‐Oran Front Using Underwater Glider Observations

“…Obvious unrealistic spikes in the physical and biogeochemical data were removed manually and replaced by an absent data value (e.g., NaN). Negative values and the dark instrument signal were removed from the chlorophyll fluorescence profiles (Zarokanellos & Jones, 2021). Chlorophyll fluorescence quenching appears mostly near the surface, and can influence fluorescence below the upper few meters, mainly in waters with a low downwelling irradiance attenuation coefficient, Kd, such as the western Mediterranean Sea.…”

Submesoscale Processes in the Upper Red Sea

“… Chlorophyll concentrations in the Red Sea observed using (a) the Moderate Resolution Imaging Spectroradiometer (MODIS‐Aqua) on 7 February 2015, revised from Zarokanellos and Jones (2021), (b) MODIS‐Aqua on 29 March 2010, revised from Raitsos et al. (2017), (c) Sea‐viewing Wide Field‐of‐View Sensor (SeaWiFS) on 16 March 2000, revised from NASA earth observatory (https://earthobservatory.nasa.gov/images/8039/chlorophyll%10and%10currents%10in%10the%10red%10sea).…”