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The Eastern Harbour of Alexandria, on the Egyptian Mediterranean coast, is characterized by environmental complications due to different types of anthropogenic stressors associated with water dynamics inside the harbor as well as the rapid water exchange with the open sea. These conditions caused chronic eutrophication conditions, with variable levels in the long term. The present study followed daily some physicochemical parameters, nutrients, and phytoplankton biomass, for a complete year. The results indicate coincidence on the short-time scale between the nutrients, phytoplankton biomass, pH, and dissolved oxygen. Spearman's correlation illustrated strong positive correlations between algal blooms and both pH and dissolved oxygen. The present study recorded twelve separate algal blooms, with an average of chlorophyll-a > 16.7 μg/L, confirming the continuity of high eutrophication in the Eastern Harbour. The seasonal Mann-Kendall tests showed that summer attained significant increasing trends for chlorophyll-a, silicate, nitrite, and nitrate, while winter has a significant decreasing trend for chlorophyll-a and pH.

Shallow hard bottom and intertidal soft bottom polychaete assemblages of the Alexandria coast, southeastern Mediterranean (Levantine Sea), were studied during a complete annual cycle in order to analyze spatial temporal patterns of variation in assemblages, and relevant factors related to polychaete distribution. The present study recorded a total of 73 species, belonging to Syllidae (22 species), Nereididae (9 species), Serpulidae (6 species), Eunicidae (5 species) and other 19 families. The assemblages experienced pronounced spatial and temporal variation throughout the study area, but spatial variation appeared more important in determining the observed patterns. Polychaete distribution related to variation of grain size and sessile macrobenthos cover suggesting that these structural variables accounted more than the physical-chemical ones (namely BOD, dissolved oxygen, organic carbon, organic matter, salinity, temperature, pH) in influencing the patterns of assemblages’ distribution. The present study is the southeastern-most one dealing with ecology and distribution patterns of hard bottom polychaetes from the Mediterranean Sea, as well as one of the few studies dealing with intertidal soft bottom polychaetes in the Levant Basin.

Nineteen benthic polychaete species were recorded for the first time inthe intertidal zone of the Alexandria coast, south-eastern Mediterranean Sea. They belong toSyllidae (7 species), Hesionidae (3 species), Serpulidae (2 species) and7 other families (one species each). Of these species Eunice miurai Carrera-Parra& Salazar-Vallejo 1998 appears to be new to the Mediterranean Sea,while four of the alien species earlier recorded in the Mediterranean were found for thefirst time in Egyptian waters: Opisthosyllis brunnea Langerhans 1879,Loimia medusa Savigny 1822, Syllis schulzi Hartmann-Schröder1960, Phyllodoce longifrons Ben-Eliahu 1972. The newly recorded species demonstrated markedly different patterns offrequency of occurrence and numerical abundance. Spirobranchus triqueterLinnaeus 1758, S. schulzi, L. medusa and Salvatoria clavataClaparède 1863 were permanent and abundant species in fouling samples along the Alexandria coast.Saccocirrus papillocercus Bobretzky 1872 persisted in the sediments at two sites,with a much higher count at the stressed one, while Protodrilussp. inhabited sediments at two other sites throughout the year, sometimes invery high numbers. In addition, the alien species found earlier, Braniaarminii Langerhans 1881, Odontosyllis fulgurans Audouin &Milne-Edwards 1833 and O. brunnea Langerhans 1879, were frequentlyobserved along the Alexandria coast.

Beginning in December 2015, an unknown bryozoan with large, deep-orange colonies began to appear in the Eastern Harbour of Alexandria, Egypt. Here we identify the species as belonging to the predominantly Indo-Pacific cheilostome genus Calyptotheca Harmer, 1957 and describe it as a new species, Calyptotheca alexandriensis n. sp. The new species exhibits intensive growth sporadically on different hard substrata, including rocks, submerged concrete walls, ropes, ships’ hulls, and metal pipes supporting marina piers. It is restricted to the Eastern Harbour, particularly in shallow parts, with the densest aggregations on the metal pier supports. The source of this bryozoan is enigmatic but most likely involved introduction by shipping.

The phytoplankton community was studied in historically and ecologically important area on the southeastern Mediterranean coast at Alexandria, Egypt. Monthly samples were collected during January-December 2009 from 2 areas [Eastern Harbor (EH) and Kayet Bey (KB)]. A total of 162 phytoplankton species were identified in the EH and 110 species in the KB, dominated by diatoms in both areas (100 and 64 species, respectively). The phytoplankton count showed an annual average of 1.387 x 10(6) cells L-1 in the EH and 0.108 x 10(6) cells L-1 in the KB, and biomass (Chlorophyll a) of 2.4 and 2.0 µg L-1, respectively. Diatoms and dinoflagellates demonstrated clearly different roles in the phytoplankton cycle in the 2 areas, with the persistent occurrence of several toxic species, sometimes in high count, like the diatom Pseudo-nitzschia delicatissima and the dinoflagellates Scrippsiella trochoidea, Pyrophacus horologium, Prorocentrum micans, Prorocentrum triestinum, Prorocentrum cordata, Gonyaulax catenata and Protoperidinium subinerme. Regardless of the stopping of great part of the discharged wastes to the study area, it is still suffering from eutrophication all the year round, as indicated from high nutrient concentrations and intensive phytoplankton growth.

The coastal area of Egypt on the Mediterranean Sea extends for about 1,200 km. It hosts a number of important residential and economic centres, like the cities of Alexandria, Port Said, Damietta, Rosetta, Matruh, and AL-Arish. The coastal strip between Alexandria and Matruh hosts tens of tourist villages, which are usually crowded by visitors during summer. Many activities are known in the coastal area, including fishing, industrial, tourism, trading and agricultural, oil and gas production, and transportation. There are five large ecologically different coastal lagoons connected to the sea coast, representing together about 25% of the total area of the Mediterranean wetland. These lagoons are considered as reservoirs for agricultural, industrial, and municipal wastes, which are discharged from surrounding cities and cultivated lands. The Egyptian Mediterranean coast receives huge volumes of wastewaters every year through the coastal lagoons and from other land-based effluents. These wastes are loaded by variable amounts and types of pollutants, in addition to great amount of nitrogenous and phosphorous compounds, which in turn cause high level of eutrophication along a significant part of the Mediterranean coast, particularly of both the Nile Delta region and Alexandria coast. Eutrophication is an importunate problem to the Egyptian Mediterranean coast, resulting in fundamental changes in the structure of the planktonic and benthic communities as well as fish mortality. Eutrophication was accompanied by the appearance of several harmful algal species at several hot spots along the coast. The level of eutrophication demonstrated wide variation along the Egyptian coast relative to the variations in the volume and contents of discharged wastes.