Fluctuations of some Physico-chemical parameters with depth in the Egyptian Mediterranean waters off Alexandria during winter 2016

Time series relationships between chlorophyll-a, physicochemical parameters, and nutrients in the Eastern Harbour of Alexandria, Egypt

“…However, the frequent algal blooms play a role in the DO fluctuations relative to the changes in the rate of the photosynthetic process which is strongly affected by the bloom density. A remarkable increase in the DO concentration values in the present study compared to those previously recorded by Salem et al (2021) and Shams El-Din et al (2015), Tadros et al (2016) was observed (Table 2).…”

“…The precise comparison between the present results and the previously recorded values cleared out that, the current average salinity value is the lowest (Table 2). It is worthy to mention that the salinity (conductivity) is played as a conservative parameter and used for measuring the dilution rate of seawater by landbased discharge, as well as salinity acts as a limiting factor and affect the distribution and abundance of the planktonic community (Salem et al, 2021). pH levels were also fairly stable (8.1 ± 0.2), remaining slightly alkaline during the study period, lower than corresponding values of the open seawater (Salem et al, 2021), and common for coastal seawater systems (Marion et al, 2011).…”

“…It is worthy to mention that the salinity (conductivity) is played as a conservative parameter and used for measuring the dilution rate of seawater by landbased discharge, as well as salinity acts as a limiting factor and affect the distribution and abundance of the planktonic community (Salem et al, 2021). pH levels were also fairly stable (8.1 ± 0.2), remaining slightly alkaline during the study period, lower than corresponding values of the open seawater (Salem et al, 2021), and common for coastal seawater systems (Marion et al, 2011). The present pH values are in agreement with that reported by Faragallah et al, (2010aFaragallah et al, ( , 2010b, they related the fluctuation of pH (from 7.5 to 8.7) to photosynthetic activities of phytoplankton and variation in water temperature.…”

“…The Egyptian Mediterranean coast recorded different levels of eutrophication relative to the variations in the quantities and qualities of the discharged wastes (Dorgham, 2011). The Eastern Harbor (EH), that locating at the western part of the Egyptian Mediterranean coast (Salem et al, 2021), is situated immediately north of Alexandria's city center and about 20-km west of the Nile Delta's northwestern coastal margin (Stanley & Bernhardt, 2010).…”

“…However, Salem et al (2021) identified the responsibility of physicochemical parameters for spatio-temporal fluctuations of aquatic organisms and stated the requirement of the examining of meteorological and hydrographical characteristics for the assessment of fertility and productivity of the aquatic ecosystem. Most of the previous studies in the EH were planned for monthly or even seasonally from various stations or designed for weekly observations from a fixed station for a small period and there is no recorded study focused on the studying of temporal variations on daily basis, that will capture the processes of shorter time scales.…”