Environmental Engineering Reference
In-Depth Information
Figure 14.
Temporal variability of the suboxic zone from 1962 to 2003. The data were
complied from the central areas of the Black Sea (updated from [25]).
Unfortunately, with the exception of Karl and Knauer [23], there is almost
no data for sinking fluxes of particulate organic matter at these depths in the
Black Sea.
Distributions of properties in the Black Sea are influenced by climate related
forcing. These fluctuations are superimposed on the anthropogenic eutrophica-
tion that occurred after the mid 1970s. Oguz and Dippner [44] have synthesized
historical data from the Black Sea. Their historical time series of winter sea
surface temperature (SST) averaged over the interior basin of the Black Sea
is shown in Fig. 16a. The SST varied from 9.25
◦
C to 7.25
◦
C from 1875
to the present. The warm periods (labeled W) and cold periods (labeled C)
vary on time scales of 5 to 10 years. Oguz and Dippner [44] showed that the
warm periods are highly correlated with the negative phase of the North At-
lantic Oscillation and the cold periods correlate with the positive NAO. The
North Atlantic Oscillation is a large scale weather system that controls the
atmospheric circulation over the North Atlantic and Eurasia. A positive NAO
corresponds to a strong pressure gradient between the Azores high and Iceland
low. Interestingly, positive NAO is associated with warm, wet conditions in
northern Europe but cold, windy and dry conditions in the Black Sea region.
