C4 Plant Productivity and Climate-CO2 Variations in South-Central Texas during the Late Quaternary
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- 作者：Nordt ; Lee C. ; Boutton ; Thomas W. ; Jacob ; John S. ; Mandel ; Rolfe D.
- 关键词：stable isotopes ; C4 plants ; buried soil ; glacial meltwater ; atmospheric CO2
- 刊名：Quaternary Research
- 出版年：2002
- 出版时间：September, 2002
- 年：2002
- 卷：58
- 期：2
- 页码：182-188
- 全文大小：126 K
文摘
A continuous record of organic carbon δ13C from a buried soil sequence in south-central Texas demonstrates: 1) strong coupling between marine and adjacent continental ecosystems in the late Pleistocene as a result of glacial meltwater entering the Gulf of Mexico and 2) ecosystem decoupling in the Holocene associated with a reduction of meltwater and a shift in global circulation patterns. In the late Pleistocene, reduction in C4 plant productivity correlates with two well-documented glacial meltwater pulses (
15,000 and 12,000 14C yr B.P.), indicating a cooler-than-present adjacent continental environment. Increased C4 production between 11,000 and 10,000 14C yr B.P. suggests that the Younger Dryas was a warm interval responding to the diversion of glacial meltwater away from the Mississippi River. With waning meltwater flow, C4 productivity generally increased throughout the Holocene, culminating in peak warm intervals at 5000 and 2000 14C yr B.P. Shifts in the abundances of C3–C4 plants through the late Quaternary show no correlation to ecophysiological responses to atmospheric CO2 concentration.
15,000 and 12,000 14C yr B.P.), indicating a cooler-than-present adjacent continental environment. Increased C4 production between 11,000 and 10,000 14C yr B.P. suggests that the Younger Dryas was a warm interval responding to the diversion of glacial meltwater away from the Mississippi River. With waning meltwater flow, C4 productivity generally increased throughout the Holocene, culminating in peak warm intervals at 5000 and 2000 14C yr B.P. Shifts in the abundances of C3–C4 plants through the late Quaternary show no correlation to ecophysiological responses to atmospheric CO2 concentration.