Spatial and temporal variations of stable isotope (delta C-13 and delta N-15) signatures of Danube waters and marine communities on the Black Sea Romanian coasts. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Cybium : Revue Internationale d’Ichtyologie Année : 2007

Spatial and temporal variations of stable isotope (delta C-13 and delta N-15) signatures of Danube waters and marine communities on the Black Sea Romanian coasts.

Résumé

Coastal marine zones located in front of large rivers are of major biological interest. The Danube is the second largest river in Europe after the Volga and represents 58% of the freshwater inputs to the Black Sea. Its delta, located between the North of Romania and the South of Ukraine, has a great impact on the sedimentation and marine ecosystems in the Black Sea. The objective of the present study was to estimate the impact of the seasonal fluctuations of the Danube particulate organic matter (POM) on the various marine trophic compartments (POM sea water, sediment, macro-invertebrates and fish) along the Romanian coasts. The ratios of the stable isotopes of carbon (C-13/C-12) and nitrogen ((15) N/N-14) allowed the identification of organic matter sources and the analysis of trophic webs. 670 analysis of stable isotopes of the particulate organic matter (POM) of the Danube water as well as marine POM, marine sediments and marine organisms (macrophytes, polychaetes, bivalves, gastropods, amphipods, macrurids, brachyurids and fishes) has been carried out on samples taken in 38 stations from the Northern, Central et Southern areas of the Romanian coasts in October 2004 and April-May 2005. The POM of the Danube presented average values of delta C-13 (-27.61 parts per thousand) and delta N-15 (4.39 parts per thousand), lower than those of the marine POM of the Black Sea (delta C-13 = -24.98 parts per thousand and delta N-15 = 7.08 parts per thousand). In the sea, the sediment presented average values decreasing from the North (delta C-13 = -20.02 parts per thousand and delta N-15 = 9.93 parts per thousand) to the South (delta C-13 = -23.59 parts per thousand, delta N-15 = 7.65 parts per thousand). Among invertebrates, stable isotope values depended on their trophic level and aptitude to consume the terrestrial POM brought by the river. The lowest values were found in polychaetes, copepods and amphipods, and the highest ones in macrurids, brachyurids and gastropods. Among the fish species studied, the lowest values of delta C-13 and delta N-15 were observed in starry sturgeon (Acipenser stellatus ponticus) and sprat (Sprattus sprattus), while the highest values was found in beluga sturgeon (Huso huso). These differences were explained mainly by differences in diet. Preliminary results showed a strong influence of the Danube particulate organic matter on the marine compartments of the Romanian coasts. The river influence decreased from the North to the South and was higher in spring when the river was flooding.
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hal-01833604 , version 1 (09-07-2018)

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  • HAL Id : hal-01833604 , version 1

Citer

Daniela Bănaru, Mireille Harmelin-Vivien. Spatial and temporal variations of stable isotope (delta C-13 and delta N-15) signatures of Danube waters and marine communities on the Black Sea Romanian coasts.. Cybium : Revue Internationale d’Ichtyologie, 2007, 31 (2), pp.167-174. ⟨hal-01833604⟩
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