Natural and anthropogenic changes in a lake-forest system in Bukovina (Romania) since 1340 AD documented by sedimentary organic geochemistry (C, N and n-alkanes). (10th November 2018)

• Record Type: Journal Article
• Authors: Karlik, Máté; Fekete, József; Mindrescu, Marcel; Grădinaru, Ionela; Bozsó, Gábor; Bíró, Lóránt; Kern, Zoltán
• Is Part Of: Quaternary international. Volume 493(2018)
• Page Start: 166
• Page End: 175
• Publication Date: 2018-11-10
• Subjects: n-alkanes -- Lacustrine organic matter -- Lake sediment -- Eastern Carpathians -- Deforestation; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quaint.2018.06.008
• Languages: English
• ISSNs: 1040-6182

Abstract

Abstract: Lake Bolătău-Feredeu is a small (surface: 0.3 ha; catchment area: 31 ha) landslide-dammed lake in Bukovina (Eastern Carpathians, Romania). Elemental concentration, stable isotope composition of carbon and nitrogen, and n-alkane composition of the saturated hydrocarbon fraction of the organic material were analyzed along the sediment profile from Lake Bolătău-Feredeu covering the past ∼700 years. The ranges of δ 13 C values (−30.5 to −26.6‰) and C/N atomic ratios (10.5 and 15.4) placed the organic material of the recent Bolătău-Feredeu sediment between the C3 Land Plants and the lacustrine algae. The n-alkane proxies provide better distinction between organic matter inputs. Detected major shifts in the n-alkane composition and the C and N concentrations along with the stable isotope compositions pointed towards three distinct stages in the environmental history of the lake-catchment system. The proxy information indicate a substantial landscape change characterized by deforestation and an increase in open pastureland with herbaceous vegetation from ∼1820. The C/N, δ 15 N, and δ 13 C values showed the highest variability probably linked to a variable lacustrine environment and decreased productivity in the catchment between ∼1640 and 1760. It can be assumed that the extended periods of lake ice cover during the cold decades experienced at the turn of the 17 th -18th centuries resulted in diminished biological productivity both in the lake and its catchment. Finally, afforestation and the decline in lake productivity have been reconstructed for the period of ∼1470–1560.