الفهرس 
Physica I mcasu rementsOnly 14 pages are availabe for public view
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Abstract
The present study wl1ich C<lrn:d out in Lake Nasser.Egypt: nimerl to update the phy sico-chemical
propcrities of the lake water (Depth. transparency, turbidity, Electric conductivity, pH,
Carbonate, Bicarbonate. Oissolved oxygen.Oxygen saturation percent age. Ch.,mical oxygen (Iemond.
Ammonium, Nitrite. Nitrate. Tmal organi nitrogen, Orthopho$phate. Sulphate. Calcium . Magnissum.
Sodium and Potasium ); Spatial distribution of phytoplankton communities (standing crop and species
cnmpo,i tion): phytoplankto n biomass as represented by chlorophyll a: and primary productivity
using f.” ll!chnique
The lake w11s investigated through 10 statioM at 3 depths (Jm, I m and ilottom walerl long
the ma.in channel from down tream at the High Dam to the Egyption border line with Sudan. The
sam11les were C\lllect d seasonally. started in January (Winter) 10 Ocl\lber (autumn} 199.1 (4
successive seasons).
The results obt int:d showed the to!lowing easonal. Variat ions :
for physico- chemical parameters;· Air temperature (16.9. 32.J.C}.
wMer temperat\lre (18.2 • 25.6°C), Dcrth (67.8 -72.8 m). secchi disc {1.92.
2.52 m), Turbidity (1.68 - 5.83 NTU). EC (198-246 11 mos), pH (7.52.
8.18). C(h (4.38-12.3 mg.l’1 . COD (J .21-10,0 mg.r’). NH;·N (28.7-113.6
Jig.!’’). N02-N(3.4-22.9 f.lg.l’1) N0.,-1’ (64.6-326.3 )lg.l’1 , TON (2.27- 11.6
1 1
1
mg.l’ ), PO,-P (1 1 .0- 125.6 11.’!.1’ }. SO, (189-3.28 mgl’ ). Ca (34.7·76.8
mg.l1}, Mg (29.9-81.4 mg.l’\ Na(125-!81 mg.l’1),and K (J.33-3.82mgl’1 .
With regard to phytoplankton populat ion, it rang d from 75.8 x t O’ units. I’’ to
132.7 .dO’ units .r’. A tota l uf 83 species have been record ed belonging to 4 main
clas!les; Cyanoph yceae (24 spp ). I.Jacillariophyceae ( I 5 spp.). Chlorophyc.:a e (JJ ,;pp.)
nnd Dinophyceac (I I spp.). Cyanophyccl\c was che first·prid ominant dass (55%1 and 4
species were newly recorded namely C/J·oocm ·,w,; limn<’ficus. Lynxhyc.t lmm tio ’·
().1-r.:illatoria liJwlcllccc . mid l’hormiJium crfricwmm.