Background An Egyptian indigenous unicellular green microalga was isolated from the coastal water of Suez Bay (N 29.92°, E 32.473°), Red Sea, Egypt. The molecular analysis based on 18S rRNA sequence showed that the gene sequence for this strain was highly similar (100% identity and 98% query cover) to different Chlorella strains isolated from different habitats. Results The observed morphological characters together with the molecular phylogeny assigned the isolated microalga as Chlorella sp. MF1 with accession number KX228798. This isolated strain was cultivated for estimation of its growth and biochemical composition. The mean specific growth rate ( μ ) was 0.273 day −1 . Both the biomass productivity and the cellular lipid content increased by increasing salinity of the growth medium, recording a maximum of 6.53 g DW l −1 and 20.17%, respectively, at salinity 40.4. Fourteen fatty acids were identified. The total saturated fatty acid percentage was 54.73% with stearic (C18:0), arachidic (C20:0), and palmitic acids (C16:0) as major components, while the total unsaturated fatty acid percentage was 45.27% with linoleic acid (C18:2c) and oleic acid (C18:1) as majors. Conclusion This algal strain proved to be a potential newly introduced microalga as one of the most proper options available for microalgae-based biodiesel production. The proximate analysis showed the protein content at 39.85% and carbohydrate at 23.7%, indicating its accessibility to various purposes.
T he present study was conducted during August 1997-August 99 to investigate the Eastern Harbour (eutrophic marine basin) environments and the corresponding phytoplankton communi ty structure, species composition and blooming of different causative organisms that are known to be inherently continuously variable. Anthropogenic eutrophication and geographical dispersion from neighbouring areas into the harbour strongly influenced such variability, and hinder any particular seasonal trends. Yet, the pronounced late winter-spring increasing population and other blooming pulses in summer and autumn caused by less than a dozen species (mainly of diatoms, eutrophication symptom) were predominant characteristics of the production cycle in the harbour, Discharge water into the harbour created rich spectra for algal growth, not necessarily for its nutrient content, but ultimately for the stabilisation of the water column, salinity fluctuation was a crucial factor limiting the phytoplankton variability. Pyramimonas and Micromonas species culminated at maximum abundance in spring with the initiation of thermo-haline stratification of the water column, and it also seems sensitive to the inter-annual variations in temperature. Dinoflagellates predominated at intermittent periods in summer well stabilized the water column, with low nitrate, and relatively high phosphate concentrations. The species-specific patterns include aspects as; the cyclic abundance of the centric diatom Skeletonema costatum', the episodic blooms of mdegenous species that normally do not show blooming in the harbour {Cyclotella narta, Leptocylindrus minimus and Lithodesmfum unduhtum); the reappearance of endogenous dinoflagellate species that were not so far recorded during the last decades (Gyrnnodinum sanguineum and Gonyaulax spinifera); and the seasonal shift in predominance and 76 Wagdy Labib trends (increasing-decreasing abundance and disappearance) of the major dinoflagellate species {Prorocenirum iriestinum, Gymnodinium caienatum and Scrippsiella trochoidea).
A yellow-brown coloration of water developed in the Eastern Harbour of Alexandria (Egypt) during April 1993. The dinoflagellate Prorocentrum triestinum, the causative organism, culminated in a population peak of 71.106 cells 1-', chlorophyll a nearly 361 pg1-'. The bloom occurred with a thermohaline stratified water column and low surface nutrient levels. Water temperature was considered a crucial environmental factor controlling the occurrence of P . triestinum and nitrate was significantly correlated with its counts. The high relative growth constant (3.4 d-'), calculated just prior to the massive occurrence of the species, explains the rapid development of the bloom. A comparison with the earlier phytoplankton studies in the harbour is made.
Despite macroalgae epiphytes play an important role in algal habitats, available information from Alexandria coastal waters is scarce. To evaluate the role of environmental factors on the inventory of the ephyphytic Ostreopsis c.f ovata cells, its abundance on the thalli of 14 different macroalgae collected from two sites at Abou Qir rocky area was done on the basis of sampling carried out for one year. The annual maximum Ostreopsis cf. ovata cell abundance was observed in May (late-spring), reaching the maximum on the green macroalgae Ulva linza in July (mid-summer). Analysis of variance showed significant difference of abundance between seasons and hosts. Water temperature and NO 2 , NO 3 and PO 4 seem the major factor affecting on abundance of Ostreopsis c.f ovata. The present study documented the significant importance of Ulva sp. as the suitable host of O. ovata in Alexandria waters, in contrasting with others in the Mediterranean Sea that show O. ovata most often found on Phaeophyta and Rhodophyta.
T he composition and the contribution of the 4 different cell size classes (>100, 50-100, 20-50 and <20 nm) of the phytoplankton population in the neritic water of Alexandria were studied over an annual cycle. Their abundance exhibited considerable variability in times. Nanoplankton contributed numerically most of the total production (58.32%, range of 4.34-95.7%), culminating its peaks during the warm seasons, while the centric diatom, Skeletonema costatum and the microflagellates, Pyramimonas sp. and Micromonas sp. were its major constituents. Netplankton dominated at high nutrient levels. However, seasonal shifts were evident. The floristic data indicated the predominance of large diatoms and dinoflagellate cells at times, influencing their relative importance to the over all standing crop population. Temperature was significantly correlated with all the size classes, except that of >100 \im 9 which seems a phosphate dependent. Salinity and silicate concentrations seem affecting the variability of the smaller size classes.
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