FRACTIONATION OF STABLE ISOTOPES OF CARBON AND SULFUR DURING BIOLOGICAL PROCESSES IN THE BLACK SEA - Past and Present Water Column Anoxia - page 382

Figure 5. Seasonal changes of the carbon isotopic composition in different areas of the Black
Sea. I - Danube river and Danube estuary; II - north-western shelf; III-VI - central part of the
Black Sea: III - euphotic zone (0-40 m); IV - decomposition zone (40-90 m); V - upper part
of the H 2 S zone (above 200 m); VI - deep-water H 2 S zone (below 200 m) 1 - Danube river,
April-May [10], 2 - Danube estuary, April-May [87]; 3 - North-Western shelf, May [87, 70]; 4 -
May [49]); 5 - August-September [58, 32]; 6 - July [70]; 7 - end of May [36]; 8 - March-April
[20].