Spatial and temporal patterns of phytoplankton composition in Burullus Lagoon, Southern Mediterranean Coast, Egypt

Burullus Lagoon is a shallow, turbid, and nutrient replete system, suffering from high level of aquatic plants, expansion in fish farming and agricultural drainage discharges. Phytoplankton was evaluated based on four years monitoring seasonally from summer 2009 to spring 2013 at 12 stations representing the eastern, central and western basins of the lagoon. Over the 4-year study period, a total of 283 taxa from 96 genera and eight classes were recorded. The lagoon showed a pronounced algal periodicity. Phytoplankton community was generally dominated by Chlorophyceae, Bacillariophyceae and Cyanobacteria. The western basin had the lowest mean salinity values and highest phytoplankton abundance, in which, blooms of Chlorophyceae, Bacillariophyceae and Cyanobacteria were common. The eastern basin had lowest phytoplankton density and chlorophytes were dominant followed by Bacillariophyceae and/or Cyanobacteria. Euglenophyceae strongly appeared in the eastern basin especially at the second station, which is located in front of El Burullus Drain. The central basin is subjecting to high loading of phosphorus and nitrogen from agricultural drains and had a prevalence of chlorophyte blooms which constituted more than 50% of the total abundance. This study has provided substantial evidence that the phytoplankton abundance and community are governed by the environmental conditions which vary each year, so does the phytoplankton seasonal succession. Generally, about 25-50% reduction was recorded in the phytoplankton densities between 2009 and 2013 and a dramatic decrease in the abundance of many nuisance and eutrophic species was evident. No sign of eutrophication was observed, and recession of Cyanobacteria blooming suggests a major improvement in the water quality of Burullus Lagoon

Variability of spatial and temporal distribution of zooplankton communities at Matrouh beaches, south-eastern Mediterranean Sea, Egypt

The objectives of this work are to determine the main environmental drivers of zooplankton variability in water of Matrouh beach, south-eastern Mediterranean Sea and to evaluate the differences in zooplankton abundance and population structure in relation to chemical and biological parameters. Samples were collected seasonally from summer 2009 to summer 2010 at 10 sampling beaches. The zooplankton community was characterized by its high variability, and lower diversity. Zooplankton variability primarily responded to seasonal changes in water temperature and variation in salinity. In total, 49 zooplankton species were quantified; most of them were protozoans (22 species) and copepods (14 species). The average zooplankton abundance was 36.0 × 103 ind. m−3, where copepods were dominant, making up 72.4% of the total population. Protozoa formed the second group, comprising 11.7%. Differences in species diversity were analysed in a zooplankton community, where the dominance of a single species was frequent. The Shannon–Wiener Diversity Index classified Matrouh water as being between moderately polluted and polluted, whereas the WQI demonstrated that it was between good and excellent. It can be concluded that, the index based on WQI is currently more suitable than the zooplankton species index for assessing the quality of water of Matrouh beaches

Phytoplankton and environmental variables as a water quality indicator for the beaches at Matrouh, south-eastern Mediterranean Sea, Egypt: an assessment

This study was carried out to determine the water quality of the beaches at Matrouh, south-eastern Mediterranean Sea, Egypt, by studying environmental variables as well as phytoplankton abundance and community structure. Surface water samples were monitored from a series of beach sites over a period of five seasons during 2009-2010. A total of 203 phytoplankton species were identified from seven algal divisions. Seasonal differences in the quantitative and qualitative composition of the phytoplankton communities in the different sites were marked. Nutrient concentrations and phytoplankton abundances were found to be poorer than those of many other areas along Egyptian coast. The Shannon-Wiener Diversity Index classified Matrouh water as being between clean and moderately polluted, whereas the WQI demonstrated that it was between good and excellent. It can be concluded that the index based on WQI is currently more suitable than the phytoplankton species index for assessing the quality of the water of the Matrouh beaches

Green technology for bioremediation of the eutrophication phenomenon in aquatic ecosystems: a review

Eutrophication is a serious phenomenon that leads to vigorous algal blooms that alters the structure of ecosystems.  It is caused by non-point sources of nutrients; as nitrogen and phosphorus, and point sources as wastewater effluent.  Distinctive algae groups are responsible for this phenomenon, such as diatoms, blue-green algae, green algae, and  dinoflagellates. Numerous solutions have been considered to control eutrophication and harmful algal blooms such  as the biological removal of nitrogen and phosphorus. Advanced treatments (i.e. green technology) depend upon  the remediation of wastewater before discharge, such as the removal of phosphorus using agricultural waste-based biosorbents (AWBs) from water and wastewater, and phosphorus sorption performance by both unmodified and modified AWBs. Phyto-remediation includes many procedures that encompass the cost-effective and environmentally friendly methods used to remove or reduce excess natural/inorganic contaminants in groundwater, surface water, and soil. Due to the rapid growth of duckweeds and their ability to rapidly remove minerals as phosphates and nitrogen from  the water, duckweed may be the most promising plant for controlling eutrophication and, therefore, harmful algal blooms

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

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

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

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

Potential effects of abiotic factors on the abundance and distribution of the plankton in the Western Harbour, south-eastern Mediterranean Sea, Egypt

Samples were collected seasonally from Western Harbour during winter 2012–winter 2013 to examine spatial and temporal variability in phytoplankton and zooplankton abundance in relation to physicochemical parameters. Water was alkaline and well oxygenated. Nutrient concentrations were generally high and related to inflow of discharged waters. A total of 157 and 106 of phytoplankton and zooplankton species were recorded, respectively. The average plankton population was 4 × 106 cells l−1 in terms of phytoplankton and 24 × 103 ind. m−3 in terms of zooplankton. Seasonal differences in the quantitative and qualitative composition of both communities in the different stations were marked. Eutreptiella belonging to class Euglenophyceae overwhelming during spring, reaching an average of 17 × 106 cells l−1. The genus previously was recorded as rare form in the Egyptian waters and may have been introduced via ballast water. Except in spring, copepods were the most abundant group and tintinnid abundances generally increased in spring. The ranges of Shannon diversity indices indicate disturbance level and sometimes high productivity. Salinity, dissolved oxygen and pH may be responsible for the variations in phytoplankton and zooplankton community structure. The results indicate that not only the discharged water make the harbour at risk, but also the ballast water is not less dangerous, and so, we emphasize the need for activation of the ballast water management IMO Ballast Water Management Conventions to reduce the risk of future species invasions