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Previous Projects: Cenomanian - Turonian OAE

This NSF funded research undertaken by Rich Barclay was aimed towards determining the cause of a particular global massive extinction that killed off 30% of marine life, some 94 million years ago.  This extinction occurred because the oceans became rapidly depleted in oxygen on a global scale.  While the lack of oxygen was the direct killing mechanism, the goal of Richard's research was to determine the causal mechanism that was driving the depletion of the oxygen.  The likely mechanism is that runaway productivity in the ocean used up the oxygen to decay the organic matter produced, creating hostile chemical conditions for marine life.  A predicted result of this is a drastic decline in atmospheric CO2.  The plants living on land during this time were sensitive to those hypothesized CO2 changes.  Using an established relationship that the number of stomatal (breathing) pores on the leaf surface is inversely proportional to the concentration of CO2 in the atmosphere, we are able to track changes of CO2 across the event.  Using fossils collected from this time period, we can directly test whether runaway productivity caused global extinction 94 million years ago.






UCD Plant Palaeoecology and Palaeobiology Group Updated: July 2013
Professor J.C. McElwain