PLANKTON OF LAKE MARYUT OUTLJrI', WEST PROM ALEXANDRIA

PLANKTON OF LAKE MARYUT OUTLJrI’, WEST PROM ALEXANDRIA
SHOUKRY K. GUERGUESS
National Insttftute of O~eanography and Fisheries. Alexandria.
ABSTRACT
The po lluted brackfsp water of lake Maryut
fs continuously pumped out the sea through
the outlet of M/IX pumping statfon (St.3).
Two canals crossing thts lake (Nubarhh canal
and Umum drafn) mfx wfth’ the lake waters before
reachfng the sea.
In order to investfgate the effect of mfxfng
of lake waters with the drain and canal waters.
saMples were regularly collected. immedfatcly
south of the lake (before IIIfxfng sts. 112).
from the outlet of the drafn (St. 3. after
mfxfng) and from the adjacent fnshore sea
water st. 4.
Drastic change~ are caused by themfxfn9
of agricultural drainage waters wfth the l&ke
waters. concerning both the water
characteristics and the phyto- and zoopllftkton
lIIsoctattons. Sal fntty increases only sl1ghtly
and the pH shows little variatfon. Oxygen
saturatfon is low in the agricultural drainage
waters. but it is further decreased by lake
waters. The adjacent ‘nshore sea waters show
recovery fn the 02 content. Mixing raises
the phosphate content to abnormally hfgh values.
The effects of eutrophication ….. reflected
on both the plankton b’omass and cOlIIpOsttion.
The COMPosition is tyPically brackfsh. the
number of specfes and the biomass .re increased
for both phyto- and zooplankton wfth IIIfxfng.