Assessment of Water Quality and Phytoplankton Structure of Eight Alexandria Beaches, Southeastern Mediterranean Sea, Egypt

Abstract

This study aims to investigate the abundance, community, and structure of phytoplankton, physicochemical parameters, and some eutrophication state indices, to estimate the water quality of eight selected beaches along the Alexandria Coast, in the southeast of the Mediterranean Sea. The samples were collected monthly from 2019 to 2020. Nutrient values ranged from 1.54 to 33.21 µM for nitrate, 0.01 to 1.98 µM for nitrite, 0.12 to 9.45 µM for ammonia, 0.01 to 1.54 µM for phosphate, and 0.67 to 29.53 µM for silicate. Phytoplankton biomass was characterized by chlorophyll-a concentration, which fluctuated between 0.12 and 12.31 µg L−1. The annual phytoplankton average was 63.85 ± 17.83 × 103 cells L−1. Phytoplankton was highly diversified (228 taxa), and the most diversified group was diatoms (136 taxa), followed by a remarkably low number of Dinophyta (36 taxa). Diatoms reached maximum abundance in December. Meanwhile, a dense bloom of microalga Chlorella marina occurred in June on some beaches. High temperature, high dissolved inorganic nitrogen, and less-saline waters have supported green algal proliferation. The Shannon–Wiener diversity index (H’) showed that there was a qualitative seasonal difference in the composition of the phytoplankton community. Waters of beaches 1–3 were classified as between clean and moderately polluted; and beaches 4–8 varied between moderately and heavily polluted. The study revealed that human activities might have triggered the algal bloom and may be responsible for alterations in the Alexandria coast ecosystem.

Combined Role of Fe Nanoparticles (Fe NPs) and Staphylococcus aureus L. in the Alleviation of Chromium Stress in Rice Plants

“…Chlorophyll is a significant component of chloroplasts and is related to plant photosynthetic rate. Any changes in chlorophyll contents can indicate plant health and plant response to environmental stress [ 4 , 52 ]. Different environmental stress can decrease the chlorophyll contents in the leaves of the plants [ 52 ].…”

“…Any changes in chlorophyll contents can indicate plant health and plant response to environmental stress [ 4 , 52 ]. Different environmental stress can decrease the chlorophyll contents in the leaves of the plants [ 52 ]. The Cr-stress drastically reduced the chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids contents in rice plants ( Figure 2 ).…”

On the Retrieval of the Water Quality Parameters from Sentinel-3/2 and Landsat-8 OLI in the Nile Delta’s Coastal and Inland Waters

“…The Egyptian Environmental Affairs Agency (EEAA) report in 2019 for the Mediterranean coast of Egypt (https://www.eeaa.gov.eg/en-us/mediacenter/reports/ projectstudies/eimp.aspx, last accessed on 28 January 2022) clarified a yearly Chl-a average of about 2 mg m −3 and range level of 0.42-5.33 mg m −3 . In addition, in situ monthly Chl-a from March 2019 to February 2020 at the beaches in Alexandria [90], located on the western part of the study area's coastal water clarified an average of 2.47 with a range level of 1.37-3.19 mg m −3 . Further, in situ Chl-a measurements for 692 points distributed in the Mediterranean Sea showed a range level of 0.01-4 mg m −3 , which were comparable to Chl-a estimated from the S3 OLCI and the CMEMS data acquired between the years 2016-2018 [91].…”

Behavioral Response in Toxicity Assessment of the Insecticide Decis® 2.5 EC toward Freshwater Zooplankton

“…In assessing the quality of aquatic ecosystems, not only laboratory tests but also in situ research are used. The assessment of the abundance and composition of phyto-and zooplankton made in this way allows not only to determine the toxicity of substances and pollution but also the characteristics of the aquatic environment, such as: hydrography, eutrophication, or seasonal variation [21,22]. Meanwhile, the results obtained in our experiment not only indicate specific changes in the tested organisms but also prove that the tests Daphtoxkit F magna and Ostracodtoxkit F can be successfully used to detect toxic residues in water in areas treated with deltamethrin and other highly toxic pyrethroid pesticides.…”