effect of sewage discharge on phytoplankton diversity in east of Alexandria coastal waters [Egypt]

Quantitative estimation of phytoplankton was carried out along the Eastern coast of Alexandria [Egypt] for three seasons, during 1991. The samples were collected from 7 sectors prependicular to the coast line from Kayet Bey to Assafra. Each sector included 3 stations situated at average water depths of 5,20 and 30 m respectively. The phytoplankton comprised 239 species included in 7 classes. the community was composed mainly of diatoms [60.3% of the total population]. The highest standing crop wad recorded in the Eastern Harbour [E.H] [30.8 x 10[3] units.1[-1]] and the lowest at Asafra [15.1 x 10[3] units. L[-1]]. The summer sustained the highest standing crop. The estimated diversity was inversely proportional to the degree of dominance of certain species and lineary related to the number of species contributing the standing crop with a simple regression equations. Multiple regression analysis illustrates also equation models for diversity in both the surface and subsrface water. Diversity index confirms a considerable improvement in the water quality of the investigated area after the construction of the new sewage system in May, 1988, which transferred the waste water discharge away from Alexandria beaches. It averaged 1.98 nats at the inshore stations and this was accompanied with a drop in the concentration of nutrients by about 36% than of the previous records in the same area, 15 years ago

Effect of application of inorganic fertilizers on the benthic fauna of the Nozha hydrodrome [Egypt]

Qualitative and quantitative estimations of bottom fauna was carried out monthly in the Nozha Hydrodrme [Egypt] during the period October, 1986 September, 1987. As a result of the reduced conditions which prevailed at the botton after prolonged additions of inorganic and nitrate fertilizers and increased eutrophication of water perior to the present investigation, the chironomus larvae and the oligochaete paranais sp. Dominated the community and contributed numerically 59.4% and 34.2% of the total benthos respectively, while gammarus spp. Formed only 6.3%. previous estimations of the benthic fauna before application of these fertilizers revealed the dominance of Corophium spp. Which constituted more than 86% by number of the total benthos while they disappeared totally in the present investigation. Also the biomass of bottom fauna has decreased from 6.3 gm fresh wt/m[2] in 1955 to 2.06 gm fresh wt/m[2]. results emphasize the importance of carrying out parallel quantitative estimations of benthos beside that of the phytoplankton and zooplankton communities during periods of application of fertilizers in order to maintain the optimum concentration levels of these fertilizers which yield the most favourable balance between these 3 components

Multivariate analysis of phytoplankton standing crop in western harbor of Alexandria [Egypt] during spring and summer

Quantitative collections of phytoplankton were performed in the western harbor during spring and summer 1989, which represent the extreme conditions of both temperature and salinity. Seventy four species were recorded, belonging to Bacillariophyceae [43], Dinophyceae [14], Chlorophyceae [10], Cyanophyceae [4], Euglenophyceae [2] and one Silicoflagellate. Although numerous species were encountered, yet very few of them formed the main bulk of the community; namely, Euglena acus, Cycotella meneghiniana, Nitzschia closterium in spring, and Prorocentrum micans, Gessnerium mochimaensis, Skeletonema costatum during summer. Also, all these species are considered as indicator of pollution with except Gessenerium sp. The average phytoplankton standing crop reached about 156 and 194 thousand units.l-1 during spring and summer, respectively. The outer part of the harbor [western sector] was more productive than the inner part [Eastern sector]. Statistical analysis dealing with the changes in community structure was concerned with univariate [diversity] and multivariate [graphical and prediction] treatments. The latter one was applied to phytoplankton community data in relation to the physicochemical parameters. Results indicated that the western harbor is mostly polluted as supported by a moderate average of diversity value of 1.44. The graphical multivariate correspondence analysis was more advantageous over both clustering and MDS plots in that it gives the natural grouping of the stations, beside evaluating the leading classes and environmental variables responsible for community change. Multiple regression analysis illustrated also excellent equations model for the phytoplankton in the western harbor during spring and summer which can be applied to predict the phytoplankton crop in the two seasons

Effect of sewage discharge on phytoplankton population in east of Alexandria coastal waters Egypt

Quantitative and qualitative estimations of phytoplankton was carried out along the eastern coast of Alexandria, Egypt, for three seasons during 1991. The samples were collected from 7 sectors perpendicular to the coast line with 21 stations. The community was composed mainly of diatoms which constituted numerically 60.3% of the total phytoplankton followed by dinophyceae [26%] chlorophyceae [9.6%] and cyanophyceae [49%], while silicoflagellates, Euglenophyceae and phenophyceae [0.13%] were rarely recorded. The phytoplankton tended to be more concentrated in the upper water layer and decreased at offshore stations. Seasonally, the highest standing crop of phytoplankton was found in summer and was dominated with diatoms coinciding with maximum sewage discharge particularly at the eastern harbor sector. Whereas, dinophyceae achieved their maximum density in spring and cyanophyceae in winter with low temperature and sewage discharge. The average value of the phytoplankton standing crop recorded during the period of investigation amounted to 18,603 units.l-1 and the high value 30,786 units.l-1 was found in the eastern harbor sector which refers to certain eutrophication condition caused by the discharge of large amounts of nutrients loaded with the sewage effluents but it decreased both eastward and away from the shore. The multiple regression analysis between variations in phytoplankton counts versus some physical and chemical parameters of water showed that the eastern region is less polluted due to the closing up most of the outfalls since May, 1988

Evaluation of the standing crop phytoplankton in some coasts of Alexandria, Egypt

The hydrographic conditions and phytoplankton communities of the four regions, namely, El-Agami, Kayet Bey, the E. H. And El-Shatbi were studied monthly from June 1991 to May 1992 in relation to the inland run off of sewage effluents and industrial wastes in the three latter regions, which create eutrophic conditions. The polluted regions of Kayet Bey, the E. H. and El-Shatbi are characterized by lower salinity, low dissolved oxygen, while the dissolved organic matter, total alkalinity and nutrient salts remained high and this was associated with high density of phytoplankton. On the other hand, El- Agami region which lies faraway from the effect of sewage pollution harbored lower density of phytoplankton which appeared more diversified. The phytoplankton composition in the investigated areas comprised 140 species, belonging to Bacillariophyceae [85], Dinophyceae [27], Chlorophyceae [14], Cyanophyceae [12], one Silicoflagellate and one Euglenophyceae. Although the communities were diversified by numerous species but the few of them formed the main bulk of the standing crop and these comprised Skeletonema costatum, Nitzschia closterium, Spirulina platensis and Asterionella japonica. The phytoplankton standing crop in Kayet Bey region attained higher density [105, 233 units L-1] than the other two polluted of the E. H. and El-Shatbi [70, 237 and 17, 443 units L-1] impacted by the highest amount of discharge of sewage water, while the minimum density was recorded at El-Agami region. Also, the seasonal variations of the phytoplankton communities in the polluted regions, controlled with the seasonal variations of the physicochemical conditions and they were more correlated to the amount of inland discharge. Generally, the present study indicated a high level of eutrophication, particularly at Kayet Bey due to the impact of big amounts of sewage effluents discharged into the area and they are usually loaded with high concentration of nutrient salt. Also, the richness in species was inversely proportional to the standing crop and the lowest number was recorded during the bloom times. Also, the dominant species all above consider as indicator for eutrophication and pollution, although the standing crop of phytoplankton was low compared to the other areas. It was recommended that sewage wastes must be treated before discharge into sea

Effect of nitrate, phosphate and salinity on the growth of the unicellular algae nannochloropsis saline and isochrysis galbana

Experiments concerning the optimization of growth concentration of nutrient salts [nitrate and phosphate] and salinity of the marine microalgae Nannochloroposis salina and Isochrysis galbana are decreased. The maximum growth rate of the former species obtained at nitrogen concentration of 9 g NO3-N L-1 and phosphorus of 0.81 mg PO4-P L-1 after 12 days incubation, which equivalent to 6 and 3 folds, respectively, of them needed for the second species to reach its maximum [1.5 mg NO3-N L-1 and 0.27 mg PO4-P L-1 at 12 and 14 days, respectively]. The highest growth of these two species was recorded at salinity ranging from 25% to 30% on sea water medium enriched with the highest concentrations of nitrite and phosphate after 12 days of cultivation [average 17 and 12 x 106 cell ml-1 of the two species, respectively]. N. Salina contained 30.62% crude protein and 19.63% ether extract, while I. galbana contained half amount of both crude protein and ether extract [15.67% and 9.12%, respectively]. Consequently, N. salina needed more nitrogen ion than the second species in their growth, due to its high content of protein. In comparison with other algae, these two species contained high content of crude protein and fat and can easily massed production as good food item for aquaculture marine organisms

Marine fouling and periphyton growths on test panels in the eastern harbour of Alexandria

The periphyton and fouling assemblage on exposed test panels were studied in the eastern harbour of Alexandria, south eastern coast of Mediterranean sea during October, 1990 to November 1991. the fouling biomasses and species composition are low. Periphyton species colonized on panels after one and two weeks included 96 species, 59 of which are diatoms. Navicula spp. And nitzschia spp. Developed well and are found in large numbers 403, 191 and 1,118, 340 cells 10[-2] cm[-2] of the panel area after one week immersion. Rich growth of periphyton species are extensively grow depends upon the duration of exposure which more dense after two weeks than one weeks. The breeding of bugula neritina and Hydroides elegans, Balanus amphitrite and algal development of ectocarpus irregularis is continued over the year. Major spawning periods probably coincide with the warmer seasons when temperature raised above 20 degree sign C. the growth of microscopic filamentous of algae and diatoms is true ecological indicator affecting on the attachment of the subsequent macro fouling organisms

effect of anionic detergents on the standing crop of phytoplankton in El-Mex bay, Egypt

El-Mex Bay is a shallow estuary, lying west of Alexandria at longitude 29 degree sign 50E and latitude 31 degree sign 10 N. Its total area is about 20 km, and the water depth fluctuates between 1.5 and 15 meters. The bay receives large amounts of drainage water contaminated with sewage and industrial wastes from Umum Drain, which averages about 6.53 million: ubi.c meter per day. The annual average standing crop of phytoplankton at the surface water and near bottom layer reached 96,560 and 25,980 units/L respectively. Chlorophytes constituted about 54.7% of the total phytoplankton in the bay [average 33.805 cells/L] They were dominated by the genera Scenedesmus, Closterium and Chlorella. Diatoms ranked as the second important class with about 24.3% of the total phytoplankton [average 15,015 cells/L]. Euglenophytes [Euglena spp] appeared less frequent, while dinoflagellates and cyanophytes persisted as rare forms. The concentration of anionic detergents in the bay water ranged between 0.0 and 1.7 mg eq. LAS/L. About 98% of the samples analysed contained less than 0.8 mg eq. LAS/L of these detergents. Regarding the seasonal variations the surface water showed an outstanding peak of phytoplankton [257,630 units/L] during spring and it consisted mostly of green algae. This was accompanied by low concentration of detergents. Lower counts of phytoplankton were recorded in the other seasons. The same seasonal cycle was observed at the bottom water but with lower counts. The sharp drop of phytoplankton counts recorded in the summer was accompanied by rapid increase of detergent concentration to an average value of 0.64 mg eq. LAS/L. Such high concentrations of detergents beside theother environmental conditions prevailing the summer season, were the main factors negatively affecting phytoplankton production. The correlation coefficients between anionic detergents and total phytop lank ton, as well as between detergents and the | different classes of ph./tu plankton. were calculated. A positive correlation between both anionic detergents and phytoplan ton during spring was proved where r= 0.78. Also high positive correlations existed between both anionic detergents and diatoms in winter [r= 0.81] and spring [r= 0.83]. Green algae gave a good correlation during spring, summer and autumn [r= 0.81, 0.83 and 0.92 respectively] while blue green algae showed good correlations during spring [r= 0.87] and summer[r=0.7 It is concluded that anionic detergent concentrations recorded In El-Mex Bay are still not toxic to phytoplankton production

Chlorophyll a Biomass of Nozha Hydrodrome, Near Alexandria, Egypt

The amount of chlorophyll A in the phytoplankton of the Nozha Hydrodrome was estimated monthly during the period from September, 1986 to August, 1987. The Hydrodrome is an artificial basin previously separated from Lake Mariut [Egypt], with a total area of 504 hectars and an average depth of 3.6 m. Application of artificial fertilizers was performed for about four and half years previous to the present investigation. Results showed that the average of chlorophyll a in surface water ranged between 1.98 mg chl.a/m[3] and 32.02 mg chl.a/m[3], with an average annual of 11.21 mg chl.a/m[3]. The near bottom water layer sustained slightly higher values of Chlorophyll A. The average annual phytoplankton biomass amounted to 0.84 mgC/1