Field and Laboratory Studies on Nile Phytoplankton in Egypt IV. Phytoplankton of Aswan High Dam Lake (Lake Nasser)

Mohammed, A. A.; Ahmed, Ahmed M.; El-Otify, Ahmed Mohamed

doi:10.1002/iroh.19890740507

Cited by 10 publications

(6 citation statements)

References 31 publications

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“…In this respect, peaks in diatom populations appeared concomitantly with the decrease of water temperature in cooler periods (Mohammed et al . , ; Jasprica & Hafner ). Conversely, diatoms were less abundant in summer, when cyanoprokaryotes were a more important element of the phytoplankton.…”

Section: Discussionmentioning

confidence: 99%

“…The highest population densities of phytoplankton were observed in winter and autumn as a result of the increase of diatoms. In this respect, peaks in diatom populations appeared concomitantly with the decrease of water temperature in cooler periods (Mohammed et al 1986(Mohammed et al , 1989. Conversely, diatoms were less abundant in summer, when cyanoprokaryotes were a more important element of the phytoplankton.…”

Section: Discussionmentioning

confidence: 99%

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Seasonal periodicity of plankton and benthic fauna community structure and diversity in a small North African reservoir

Iskaros

El-Otify

2012

Water & Environment J

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Aquatic biota in terms of phytoplankton, zooplankton and benthic fauna were qualitatively and quantitatively followed seasonally during 2007 in a North African small reservoir, Aswan Reservoir. Simultaneously, seasonal variations in water quality were investigated in order to determine how far the aquatic biota could be altered by physicochemical and biotic factors. In phytoplankton of the investigated reservoir, 75 species belonging to four systematic groups were recorded, comprising 11 Cyanoprokaryota, 24 Bacillariophyceae, 2 Dinophyceae and 38 Chlorophyceae. Most numerous zooplankton were Rotifera (23 species). Cladocera and Copepoda were less numerous, with only seven and three species, respectively. Early development stages of copepods, nauplii and copepodites were sometimes recorded in considerable numbers. Twenty‐two invertebrate species related to five animal groups were exclusively benthic fauna: three Oligochaeta, nine Mollusca, seven larvae of Chironomidae, one Platyhelminthes, one Hirudinea and one Decapoda. Generally, the estimated values of phytoplankton species richness were relatively higher than those of zooplankton or benthic fauna. In particular, phytoplankton was influenced by physicochemical factors – water transparency, salinity and soluble reactive silica contents – as well as biotic factors – zooplankton and benthic fauna. Levels of pH value, Mg+2, NO3‐N and chlorophyll‐a contents appeared to be the most influential parameters dictating the pattern of seasonal periodicity of benthic fauna. Numerically, the phytoplankton was somewhat more abundant in winter and autumn than in spring or summer. The peak of zooplankton population densities was observed in spring season. Benthic fauna tended to be abundant in summer and autumn seasons, showing a reverse seasonal trend from that of zooplankton. Cyanoprokaryota and Bacillariophyceae were the most important groups that determined the seasonal fluctuation pattern of phytoplankton. Rotifera and Copepoda were the most predominant groups influencing the seasonal periodicity of zooplankton. Oligochaeta and Mollusca alternated the dominancy of benthic fauna community in Aswan Reservoir.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Seasonal periodicity of plankton and benthic fauna community structure and diversity in a small North African reservoir

Iskaros

El-Otify

2012

Water & Environment J

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“…From April to July under stratified conditions the epilimnion usually shows oxygen supersaturation (up to 160 or 200%) in the lacustrine part of the lake (Entz 1997). Mohammed et al (1989) suggested that oxygen concentrations above the saturation level are often resulted by the assimilation activity of the existing phytoplankton. Thermal stratification coincides with the formation of well-oxygenated epilimnion and an oxygen-free hypolimnion layer (Elewa 1980, Latif andElewa 1980).…”

Section: Physico-chemical Analyses and Phytoplankton In Lake Nasser 91mentioning

confidence: 99%

Analyses of physico-chemical characteristics and phytoplankton communities of Lake Nasser during the last two decades

El-Otify¹,

Shafik²,

Szőke³

2003

Acta Botanica Hungarica

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Lake Nasser is one of the largest man-made lakes in the world. The creation of Lake Nasser, due to the impoundment of the River Nile in Southern Egypt, was accompanied by alterations in the environmental conditions that consequently affect the biota. Such alterations lead to corresponding changes in the diversity, abundance and distribution of the phytoplankton community. Therefore, the phytoplankton populations were followed and investigated in Lake Nasser. The phytoplankton community structure revealed a floristical diversity and is composed of various planktonic algal taxa appertaining to the divisions: Chlorophyta, Bacillariophyta (diatoms), Cyanophyta (cyanobacteria), Dinophyta (Dinoflagellates) and Euglenophyta. Chlorophyta contribute more taxa to the phytoplankton than any other groups. However, diatoms and cyanobacteria are numerically the main components and alternate in dominance of the community. Dinoflagellates persist as frequent forms and the euglenoid algae are very scarcely represented. Remarkable spatial (horizontal and vertical) as well as temporal (seasonal) variations are recorded in the distribution of phytoplankton. Pronounced variations in the vertical distribution of the phytoplankton standing crop appear during the periods of thermal stratification (late spring, summer and early autumn). However, diatoms and cyanobacteria remain the most influential groups also in the vertical distribution of the phytoplankton. Water blooms are occasionally observed in limited areas of the southern region of Lake Nasser mainly due to the florishment of the cyanobacterium Microcystis aeruginosa.

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“…Excessive dam and floodgate construction obstruct river flow, resulting in environmental degradation and biodiversity reduction (Berkamp et al 2000). It was revealed that the Aswan Dam has seriously altered the ecological balance of the Nile River Basin and caused a series of environmental disasters such as soil salinity downstream of dam, the shrink of river mouth delta, the schistosomiasis endemic (Mohammed et al 1989;Sadek et al 1997;Selim et al 2002;Stanley and Wingerath 1996). The similar problems also happened in other places such as Kenya (Bartholow et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Impact of Water Projects on River Flow Regimes and Water Quality in Huai River Basin

Zhang

Xia

Liang

et al. 2009

Water Resour Manage

163

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Field and Laboratory Studies on Nile Phytoplankton in Egypt IV. Phytoplankton of Aswan High Dam Lake (Lake Nasser)

Cited by 10 publications

References 31 publications

Seasonal periodicity of plankton and benthic fauna community structure and diversity in a small North African reservoir

Seasonal periodicity of plankton and benthic fauna community structure and diversity in a small North African reservoir

Analyses of physico-chemical characteristics and phytoplankton communities of Lake Nasser during the last two decades

Impact of Water Projects on River Flow Regimes and Water Quality in Huai River Basin

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