The first high resolution diatom record from Lake Balaton, Hungary in Central Europe

Abstract

espanolAqui se presenta un registro de diatomeas de alta resolucion del lago Balaton de los ultimos 7500 anos, un gran lago calcareo poco profundo en Europa Central. Los analisis de diatomeas se llevaron a cabo en un testigo sedimentario de 112 cm de longitud obtenido en la cuenca Siofok (parte oriental del lago), combinado con perdidas por ignicion (LOI), mediciones geoquimicas y analisis de tamano de grano. En este estudio se distinguieron 140 taxones de diatomeas; Amphora pediculus, Cocconeis neothumensis, Fragilaria brevistriata y Karayevia clevei fueron miembros frecuentes y ubicuos de los conjuntos de diatomeas. Los taxones de Fragilaroides eran dominantes a traves del testigo en el somero lago Balaton, pero los episodios de mayor proporcion de formas planctonicas (Lindavia balatonis, Aulacoseira granulata y Pantocsekiella ocellata) antes de ca. 2000 calyr BP, indicaron un nivel de agua alto en el lago y una fluctuacion mas fuerte que la que existe hoy en dia. La reconstruccion del nivel del lago basada en diatomeas estuvo de acuerdo con los registros geoquimicos y zoologicos, demostrando la utilidad de los restos siliceos en reconstrucciones paleolimnologicas en el lago Balaton, a pesar de las condiciones de preservacion desfavorables EnglishA high-resolution diatom record of the last 7500 years of Lake Balaton, a large, shallow calcareous lake in Central Europe is presented here. Diatom analyses were carried out on a 112 cm long core obtained from the Siofok Basin (eastern part of the lake) combined with loss-on-ignition, geochemical measurements and grain-size analysis. Altogether 140 diatom taxa were distinguished in this study; Amphora pediculus, Cocconeis neothumensis, Fragilaria brevistriata and Karayevia clevei were frequent and ubiquitous members of diatom assemblages. Fragilaroid taxa were dominant through the core in the shallow Lake Balaton, but episodes of higher ratios of planktic forms (Lindavia balatonis, Aulacoseira granulata and Pantocsekiella ocellata) before ca. 2000 cal yr BP, indicated high water level in the lake, and stronger fluctuation than exists today. The diatom-based reconstruction of lake level was in accordance with the geochemical and zoological records, proving the usability of siliceous remains in paleolimnological reconstructions in Lake Balaton, in spite of the unfavourable preservation conditions.