نتایج جستجو برای: glacial period

تعداد نتایج: 500154  

2011
Joy K. Ward Laci M. Gerhart John M. Harris Jesse B. Nippert Darren R. Sandquist

• While studies of modern plants indicate negative responses to low [CO2] that occurred during the last glacial period, studies with glacial plant material that incorporate evolutionary responses are rare. In this study, physiological responses to changing [CO2] were compared between glacial (La Brea tar pits) and modern Juniperus trees from southern California. • Carbon isotopes were measured ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2005
Joy K Ward John M Harris Thure E Cerling Alex Wiedenhoeft Michael J Lott Maria-Denise Dearing Joan B Coltrain James R Ehleringer

The Rancho La Brea tar pit fossil collection includes Juniperus (C3) wood specimens that 14C date between 7.7 and 55 thousand years (kyr) B.P., providing a constrained record of plant response for southern California during the last glacial period. Atmospheric CO2 concentration ([CO2]) ranged between 180 and 220 ppm during glacial periods, rose to approximately 280 ppm before the industrial per...

Aims & Backgrounds: The Quaternary period is considered as the interval of climatic oscillations (glacial and interglacial) coupled with tectonic episodes. Therefore, tectonics and climate have simultaneously governed the evolution of Quaternary alluvial fans. Unraveling the tectonic and climatic factors under varied depositional systems is therefore the fundamental issue in understanding the e...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید