Biochemistry

Keystone Symposia - Granlibakken Resort, Tahoe City, California, USA

Gordon Research Conferences - Four Points Sheraton / Holiday Inn Express, Ventura, California, USA

Gordon Research Seminar - Proctor Academy, Andover, New Hampshire, USA

Gordon Research Conferences - Proctor Academy, Andover, New Hampshire, USA

Gordon Research Conferences - Mount Snow Resort, West Dover, Vermont, USA

Gordon Research Seminar - University of New England, Biddeford, Maine, USA

Gordon Research Conferences - University of New England, Biddeford, Maine, USA

A 30 m.y. stable isotopic record of marine-deposited black carbon from regional terrestrial biomass burning from the northern South China Sea reveals photosynthetic pathway evolution for terrestrial ecosystems in the late Cenozoic. This record indicates that C3 plants negatively adjusted their isotopic discrimination and C4 plants appeared gradually as a component of land vegetation in East Asia since the early Miocene, a long time before sudden C4 expansion occurred during the late Miocene to the Pliocene.

The oxygen isotope composition of marine diatoms from hydraulic piston-cored samples of DSDP Site 480 vary widely, reflecting the great temperature variations and large isotopic changes of surface water in the Gulf of California. Nevertheless, the results can be correlated with standard oxygen isotope records for the late Quaternary based on carbonates (such as the record of core V19-29).

Oxygen and carbon isotopic gradients in surface waters were reconstructed for the past 450 kyr by analysis of the planktic foraminifer Neogloboquadrina pachyderma in cores located at approximately 43?, 47?, and 54?S across the Polar Frontal Zone in the South Atlantic sector of the Southern Ocean. Comparison of the oxygen isotopic records for peak interglacial conditions during the past 450 kyr reveals that Marine Isotope Stage (MIS) 11 was not substantially warmer than other interglacials at high southern latitudes, although the period of warmth lasted longer.