Categories
vol-25EFFECT OF TEMPERATURE, SALINITY, LIGHTAND
SELECTED NUTRIElvTS ON THE GROWTH OF THE
DINOFLAGELLATE GYMNODINIUM CATENA TUM (GRAHAM)
UNDER CULTURAL CONDITIONS
By
,WAGDY LABIB*
*Nationallnstitute ofOceanograph.:v & Fisheries, Kayet Bey, Alexandria, Egypt.
Key Words: Gymnodinium catenatu~ cultural conditions
ABSTRACT
The chain-forming dinoflagellate, Gymnodinium catenatum, was
cultured from vegetative cells isolated from Mex Bay, west ~f
Alexandria (Egypt). Its optimal growth occurred at a temperature of o ‘) 1 25 C, 30 salinity and light intensity of500 JiE’ m–‘s- (12: 12 W cycle).
The growth rate (f1}j during the exponential phase varied between
0.19 and 0.57 d 1
, mean doubling time 2.8 – 3.8 days. Limitedgrowth
was obsenJed at the low temperature 15 0
C and the high sa/i.llity of35.
Low light illumination in the dark-light cycle caused higher growth
than the continuous high light. This dinoflagellate grew best at a
combination of ammonia and phosphate concentrations (doubling
time 0.97 – 1.10 days). Implication for the bloom dynamics ofG.
catenatum in the neritic waters of Alexandria was discussed The
results ofthe present cultural experiment coincided well with the field
observations.
