Naslov
Isotope and chemical analyses of the surface lake sediments in two karstic lakes, Plitvice Lakes, Croatia

Autori
Sironić, Andreja ; Horvatinčić, Nada ; Barešić, Jadranka ; Borković, Damir

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts - ESIR Isotope Workshop / Krajcar Bronić, Ines ; Horvatinčić, Nada ; Obelić, Bogomil - Zagreb : Institut Ruđer Bošković, 2015, 81-81

ISBN
978-953-7941-08-6

Skup
ESIR Isotope Workshop XIII

Mjesto i datum
Zadar, Hrvatska, 20.09.2015. - 24.09.2015

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
14C; 13C Isotopes; lake sediments; Plitvice Lakes

Sažetak
In the frame of the Croatian Science Foundation Project “Reconstruction of the Quaternary environment in Croatia using isotope methods“ part of investigation refers to the study of recent lake sediments in two karstic lakes from the Plitvice Lakes system. Lake sediments may provide a continuous, high-resolution record of environmental changes within the lakes’ ecosystem and regional catchment and have been used widely to study natural environmental changes or human-induced impact. For this study we selected two lakes where surface lake sediments (top 40 cm) were taken by gravity corer at several locations. Sediment cores were taken in a big lake, Prošće (area 6.8 km2, max. depth 42 m), at 6 locations and in a small lake, Kaluđerovac (area 0.2 km2, max. depth 14.5 m), at 3 locations. The sediment cores were taken at different water depth and at different distances from the coast. In the sediment profiles (~40 cm long) analyses of a14C and delta13C of carbonate and organic fraction and CHN analyses have been performed, and mineralogical composition will be determined. The preliminary results of the first year of the Project presented in this study included 3 sediment cores from Lake Prošće: at the mouth of the Matica River on 1 m depth, at the Liman bay, 5 m depth, and at the deepest point of the lake, 42 m, and 3 cores from Lake Kaluđerovac: on 1.7 m depth, on 4.5 m depth, both near the shore on the SE of the lake and at the deepest point of the lake, 14.5 m depth. a14C and delta13C values indicated different ratio of authigenic and allogenic fractions at different sampling points at Lake Prošće, as well as an implication of the stronger influence of the water current at the mouth of the Matica River. Strong influence of photosynthesis and calcite precipitation from dissolved inorganic carbon was observed at the deepest points of both lakes. The CHN analyses also showed stronger influence of allochtonous organic material in Lake Prošće, increasing near to the mouth of the Matica River. The composition of Lake Prošće sediment varied for different locations, e.g. carbonate fraction from 20 to 80 %, organic fraction from 16 to 20 % and C/N ratio from 16 to 19. The composition of sediment from Lake Kaluđerovac was similar at all three locations ; carbonate fraction was ~95 %, organic fraction ~1 % and C/N ~11, implying that here autochtonous material prevails. The preliminary data showed that isotope and CHN analyses in several sediment cores taken from different micro locations in two lakes can provide important information on paleoenvironmental changes, and also help in predicting future trends in environmental evolution following the global and local/regional influence of these changes. The work was performed within the project 1623 "Reconstruction of the Quaternary environment in Croatia using isotope methods" financed by the Croatian Science Foundation.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Kemija

POVEZANOST RADA