SEASONAL VARIATIONS IN THE STANDING STOCK OF PHYTOPLANKTON NEAR JEDDAH, RED SEA.

SEASONAL VARIATIONS IN THE STANDING STOCK OF
PHYTOPLANKTON NEAR JEDDAH, RED SEA.
ASDEL – GHANI N. KHALIL· AND AHMED M. IBRAHIM··
*Oepartment of Oceanography. Faculty of Science. Alexandria University. Egypt.
**Jnstitute of Oceanography and Fisheries, Alexandria. Egypt.
ABSTRACT
Seasonal varfatfons in the standfng crops of
phytoplankton (measured as cell numbers and as
chlorophyll a content) of the coastal waters at
three sftes near Jeddah, were fnvestigated. Autumn
represents the most productive season around the
year. One peak of chlorophyll a concentratfon was
observed fn November, .mereas the lowest value was
estfmated 1n May. The .easonal varfatfons fn the
chlorophyll a concentration follows a sfmflar pattern
of the standfng crop of the phytoplankton. lower
values of chlorophyll a content were noticed .men
the number of dfnoflagellate specfes surpassed th,t
of the dfatOalS.
The coastal waters of Jeddah area are oIfqotrophfc
during most Of the year and comparable to the central
part of Red Sea. However, variatfons in chlonlphyl1
a content and standfng crop of the phytoplankton
may be attrfbuted to the preval1 fng ecol091 cal
condftfons.