SOME PHYSICO CHEMICAL INDICES Of ~UTROPIIICATION IN THE EASTERN lIARBOUR OF Al.EXANDRIA.

SOME PHYSICO CHEMICAL INDICES Of ~UTROPIIICATION
IN THE EASTERN lIARBOUR OF Al.EXANDRIA.
FATMA ABD EL-RAHMAN ZAGlILOUL
Natfonal Instftute of Oceanography and Flsher1es, Alexandria, E9Ypt.
ABSTRACT
The hydrographic condftions In the Eastern
Harbour ( E.H.) have been studied in the
period from August 1986 ~o July 1987 in
relation to the domestfc sewage discharge,
which creates eutrophic conditions. The
t.H. Is a strongly stratified two layer
system most of the year, consisting ot a
dilute sUrface layer characterized by lower
salinity, low dissolved oxygen, high dIssolved
phosphate and silicate. high specific
alkalinity, low Secchl disc transparency
and a dense phytoplankton standing crop.
The more sa Hne bottom layer is
characterized by a higher density, lower
dissolved oxygen, particularly along the
inner margin station, lower dissolved silicate
, lower specific alkalinity and lower
phytoplankton crop.
Stratification becomes Interrputed during
the mixing period from November to February.
The E.”. then becomes almost homohaline
and homothermal, with a general rise In
salinity and In the oxygen relative percent
saturation. The specific alkalinity becomes
nearer to that of the open sea and the pH
Is minimal, the phytoplankton standing crop
is .1so at Its minimum.