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001-es BibID:	BIBFORM084456
Első szerző:	Magyari Enikő (biológus)
Cím:	A 13,600-year diatom oxygen isotope record from the South Carpathians (Romania): Reflection of winter conditions and possible links with North Atlantic circulation changes / Magyari Enikő Katalin, Demény Attila, Buczkó Krisztina, Kern Zoltán, Vennemann T., Fórizs István, Vincze Ildikó, Braun Mihály, Kovács István János, Udvardi Beatrix, Veres Dániel
Dátum:	2013
ISSN:	1040-6182
Megjegyzések:	This study provides a continuous lateglacial and Holocene record of diatom silica oxygen isotope changes (?18ODIAT) in a subalpine lake sediment sequence obtained from the Retezat Mts (Taul dintre Brazi, 1740 m a.s.l.). This through-flow, shallow, high-altitude lake with a surface area of only 0.4 ha has short water residence time and is predominantly fed by snowmelt and rainwater. Its ?18ODIAT record principally reflects the oxygen isotope composition of the winter and spring precipitation, as diatom blooms occur mainly in the spring and early summer. Hence, changes in ?18ODIAT are interpreted as seasonal scale changes: in the amount of winter precipitation. Low oxygen isotope values (27-28.5?) occurred during the lateglacial until 12,300 cal BP, followed by a sharp increase thereafter. In the Holocene ?18ODIAT values ranged from 29 to 31? until 3200 cal BP, followed by generally lower values during the late Holocene (27?30?). Short-term decreases in the isotopic values were found between 10,140-9570, 9000?8500, 7800?7300, 6300?5800, 5500?5000 and at 8015, 4400, 4000 cal BP. After 3200 cal BP a decreasing trend was visible with the lowest values between 3100?2500 and after 2100 cal BP The general trend in the record suggests that contribution of winter precipitation was generally lower between 11,680 and 3200 cal BP, followed by increased contribution during the last millennia.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Quaternary International. - 293 (2013), p. 136-149. -
További szerzők:	Demény Attila Buczkó Krisztina (1962-) (biológus) Kern Zoltán Vennemann, Torsten Fórizs István Vincze Ildikó Braun Mihály (1966-) (vegyész, analitikus) Kovács István János Udvardi Beatrix (Budapest) Veres Dániel
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001-es BibID:	BIBFORM079444
Első szerző:	Magyari Enikő (biológus)
Cím:	Radiocarbon chronology of glacial lake sediments in the Retezat Mts (South Carpathians, Romania): a window to Late Glacial and Holocene climatic and paleoenvironmental changes / Magyari Enikő K., Braun Mihály, Buczkó Krisztina, Kern Zoltán, László Péter, Hubay Katalin, Bálint Miklós
Dátum:	2009
ISSN:	1788-2281 1789-3348
Megjegyzések:	As a first piece in a series of Late Quaternary paleoecological studies on the glacial lake sediments of the Retezat Mountains, this study discusses radiocarbon chronology and sediment accumulation rate changes in two sediment profiles in relation to lithostratigraphy, organic content, biogenic silica and major pollenstratigraphic changes. A total of 25 radiocarbon dates were obtained from sediments of two lakes, Lake Brazi (TDB-1; 1740 m a.s.l.) and Lake Gales (Gales-3; 1990 m a.s.l.). Age-depth modeling was performed on TDB-1 using calibrated age ranges from BCal and various curve-fitting methods in psimpoll. Our results suggest that sediment accumulation began between 15,124?15,755 cal yr BP in both lakes and was continuous throughout the Late Glacial and Holocene. We demonstrated that local ecosystem productivity showed delayed response to Late Glacial and Early Holocene climatic changes in the subalpine and alpine zones most likely attributable to the cooling effect of remnant glaciers and meltwater input. However, regional vegetation response was without time lag and indicated forestation and warming at 14,450 and 11,550 cal yr BP, and cooling at ca. 12,800 cal yr BP. In the Holocene one major shift was detected, starting around 6300 cal yr BP and culminating around 5200 cal yr BP. The various proxies suggested summer cooling, shorter duration of the winter ice-cover season and/or increasing size of the water body, probably in response to increasing available moisture.
Tárgyszavak:	Természettudományok Környezettudományok idegen nyelvű folyóiratközlemény hazai lapban folyóiratcikk Late Glacial radiocarbon dating loss-on-ignition pollen glacial lake sediments rapid climate change
Megjelenés:	Central European Geology. - 52 : 3-4 (2009), p. 225-248. -
További szerzők:	Braun Mihály (1966-) (vegyész, analitikus) Buczkó Krisztina (1962-) (biológus) Kern Zoltán László Péter Hubay Katalin (1985-) (biológus, környezetkutató) Bálint Miklós
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