DOI: 10.1016/j.quascirev.2012.10.032
Scopus记录号: 2-s2.0-84881374951
论文题名: Benthic ostracode δ13c as sensor for early holocene establishment of modern circulation patterns in central europe
作者: Schwalb A. ; Dean W. ; Güde H. ; Hanisch S. ; Sobek S. ; Wessels M.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2013
卷: 66 起始页码: 112
结束页码: 122
语种: 英语
英文关键词: Central Europe
; Early Holocene
; Lake sediments
; Methanogenesis
; North Atlantic Oscillation
; Ostracodes
; Stable carbon and oxygen isotopes
; Tetrahymanol
Scopus关键词: Central Europe
; Early Holocene
; Lake sediments
; Methanogenesis
; North Atlantic oscillations
; Ostracodes
; Stable carbon
; Tetrahymanol
; Atmospheric pressure
; Biogeochemistry
; Biological materials
; Climate change
; Isotopes
; Lakes
; Magnetic susceptibility
; Methane
; Organic compounds
; Oxygen
; Sediments
; Water
; Carbon
; adult
; anoxic conditions
; benthos
; bottom water
; carbon isotope
; concentration (composition)
; deglaciation
; Holocene
; lacustrine deposit
; methanogenesis
; North Atlantic Oscillation
; ostracod
; oxygen isotope
; paleoecology
; paleotemperature
; photosynthesis
; sediment core
; sediment-water interface
; shell
; surficial sediment
; Atlantic Ocean
; Atlantic Ocean (North)
; Central Europe
; Mirabilis
; Ostracoda
英文摘要: Shells from adult specimen of the benthic ostracodes Limnocytherina sanctipatricii and Leucocythere mirabilis selected from a 8.7 m long piston core provide continuous stable oxygen and carbon records for the past approximately 16 ka. Oxygen isotopes from both species show identical values and track the general North Atlantic and European temperature history since deglaciation in great detail. Values of ostracode δ18O values suggest that about 16 cal ka the average annual air temperatures were about 11°C colder than today. Carbon isotopic values from both species of ostracodes are similar during the Lateglacial and early Holocene, and show an overall decrease from -4% to -7%that is probably related to an increase in photosynthetic productivity in the water column, as suggested by an increase in organic carbon, delivering 13C-depleted organic matter to the bottom waters (carbon pump). About 9 cal ka only L. mirabilis δd13C values decreased about -2.5% within 300 years. Higher δ13C variability and ecological evidence suggests that L. mirabilis represents a summer signal, whereas L. sanctipatricii displays a more subdued annual average. After about 7 cal ka another -1.5% decrease for both species, accompanied by an increase in magnetic susceptibility, a decrease in carbonate content, and more positive bulk carbonate isotope values followed, suggesting higher detrital-clastic input into the lake. In order to provide a possible mechanism explaining the negative L. mirabilis δ13C-values, sediment pore water profiles of O2 and CH4 in short cores collected from sites distal to proximal to the Alpine Rhine River delta, were inspected. Sediments in cores from more proximal sites to the Rhine delta become anoxic at shallower sediment depth due to the decay of high allochthonous organic carbon input to the sediment, which greatly increases concentrations of methane in pore waters closer to the Rhine inflow. When methane is oxidized close to the sedimentewater-interface, 13C-depleted carbon is added to pore water DIC that is then available for incorporation into ostracode shells. This mechanism suggests that about 9 cal ka the oxygen supply to the bottom waters, especially in summer, decreased. This stimulated methanogenesis close to the sedimentewater-interface, and provided δ13C-depleted carbon to benthic dwellers. Independent evidence for methanogenesis is provided by the increase in concentration of tetrahymanol after about 9 cal ka coincident with the decrease in δ13C of L. mirabilis. We suggest that about 9 cal ka the northward retreat of the Northern Hemisphere Ice Sheets, and consequently the polar front, left the alpine region affected by a more oceanic climate, characterized by warmer winters as they occur today especially during the positive North Atlantic Oscillation Index phase. More frequently incomplete mixing of the water column may have shifted the decay of organic matter faster to anaerobic conditions in surficial sediments especially during summer. By about 7 cal ka the North Atlantic region had probably warmed sufficiently to increase precipitation in Central Europe and consequently detrital-clastic runoff to Lake Constance. © 2012 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60743
Appears in Collections: 过去全球变化的重建
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作者单位: Institut für Geosysteme und Bioindikation, Technische Universität Braunschweig, Langer Kamp 19c, D-38106 Braunschweig, Germany; U.S. Geological Survey, Federal Center, Box 25046, MS 980, Denver, CO, United States; Institut für Seenforschung, LUBW, Argenweg 50/1, D-88085 Langenargen, Germany; Alfred-Wegener-Institut für Polar- und Meeresforschung, Postfach 120161, D-27515 Bremerhaven, Germany; Department of Ecology and Genetics, Limnology, Uppsala University, Norbyvägen 18D, SE-75236 Uppsala, Sweden
Recommended Citation:
Schwalb A.,Dean W.,Güde H.,et al. Benthic ostracode δ13c as sensor for early holocene establishment of modern circulation patterns in central europe[J]. Quaternary Science Reviews,2013-01-01,66