Environmental Engineering Reference
In-Depth Information
13
C, ‰) in water samples from north-western
Table 8.
The isotopic composition of POC (δ
shelf collected in different seasons.
N
Place of sampling
Time of sampling
δ
13
C,
‰
Reference
1
Danube river
April 1997
-28.1
[10]
−
24.4
÷−
31.5 [7]
2
Dniper mouth
May 1997
-29.0
[70]
−
÷−
28.5
29.5 [2]
3
Dnister mouth
May 1997
-28.5
[70]
−
28.2
÷−
28.8 [2]
4
North-western
May 1997
-26.07
[70]
shelf
−
24.4
÷−
28.8 [15]
5
North-western
April-May
-25.0
[10]
shelf
1997
−
22.3
÷−
27.7 [7]
6
Danube-Black
April-May
-26.66
[87]
Sea mixing
1997
−
24.3
÷−
28.3 [21]
zone
7
North-western
May
-25.3
[50]
shelf
1998
−
24.2
÷−
27.1 [7]
8
North-western
August
-20.0
[70]
shelf
1995
−
19.3
÷−
20.7 [2]
9
North-western
September-
-21.46
[58]
−
÷−
shelf
October 1992
20.6
22.2 [10]
13
C ‰;
Numerator - the average δ
13
C; number in brackets - number of samples.
denominator - range of δ
13
C of POC in summer of 1995 and early autumn of 1992 was very different.
In the fall the input of terrigenous material and the phytoplankton production
were low (Table 8, No. 8 and 9).
Table 9 shows published data on the isotopic composition of POC in the
upper water column of the deep Black Sea. These data demonstrate that seasonal
dynamics of δ
δ
13
C of POC is characteristic not only for the north-western shelf,
but for the whole sea as well. Samples of POC collected in spring [24] and during
summer phytoplankton bloom [58] are less depleted in
13
C than the samples
that we [50] and Fry et al. [36] collected in May during low phytoplankton
production [9] (Fig. 4). The chart (Fig. 5) shows data for δ
13
C of POC for two
contrasting (by primary production) periods. The average data between two
seasons differ by 2.5 - 4.2‰.
