EXCHANGE OF PHOSPHORUS FORMS BETWEEN WATER AND SEDIMENT IN LAKE EDKU, ALEXANDRIA, EGYPT

EXCHANGE OF PHOSPHORUS FORMS BETWEEN WATER
AND SEDIMENT IN LAKE EDKU, ALEXANDRIA, EGYPT
HAYAT M.M. FARAGALLAH
National Institute of Oceanography and Fisheries, Alexandria, Egypt
Keywords: Lake Edku, pore water, overlying water and phosphorus.
ABSTRACT
Bottom water and grab sediment samples were collected from eleven selected stations
from lake Edku in spring season (May), to see the abundance and distribution of different
phosphorus (P) fractions between the water and the sediments. The results showed that, the
pore water recorded much higher concentrations of dissolved inorganic phosphorus (DIP)
and dissolved organic phosphorus (DOP) than that in the overlying bottom water
(enrichment factor, EF = 5.18 and 31.43, respectively). This means that the sediments of
the lake act as a source of the two phosphorus forms. DIP constitutes the majority of total
dissolved phosphorus (TDP) in the sediment pore water and in the overlying bottom water
(75.40 % and 87.87 %, respectively). The rate of diffusion of DOP from the sediment pore
water to the overlying bottom water is most likely greater than that of DIP. This reflects
that most OP in the bottom water was diffused from the sediments, but the drainage water
was the most responsible about the high level of IP in the overlying bottom water.