Environmental Engineering Reference
In-Depth Information
13
C of POC collected at 5 stations in various zones of the Black Sea in
September 1992 (Fig. 3).
on δ
Figure 3.
Stations sampled for POC isotopic composition: 1 - March-April 1969 [24]; 2 -
May 1989 [36]; 3 - September-October 1992 [58]; 4 - May 1997 [70]; 5 - May 1998 [50].
We analyzed the isotopic composition of POC obtained at ten stations on the
north-western shelf and at 4 stations in the deep water zone of the Black Sea
(Fig. 3) [50, 70]. Figure 5 shows all data onδ
13
C of POC in the water column of
the Black Sea. The isotopic studies of POC during cruises of 1995-1997 of the
International Project EROS 21 [63] have been conducted in the north-western
zone of the Black Sea [10, 70, 87]. One of the goals was to find out the isotopic
composition of terrigenous organic matter flowing into the Black Sea from
Danube, Dniper, and Dniestr. These rivers account for a half of the total river
discharge in the Black Sea.
Important data on the isotopic composition of POC of terrigenous origin
were obtained from the Danube delta in April 1997 as well as from the zone
near the mouth of Dniper and Dniestr in May 1997. The average δ
13
CofPOC
in seven samples collected in three zones was -28.1‰ (ranging from -24.4‰
to -31.5‰) (Table 8, No. 1-3). The samples of POC collected in spring 1977
over the shelf area at various distances from the river mouth were less depleted
in
13
C because of the presence of the isotopically heavy plankton (Table 8, No.
4-7).
