This award is for support of a study of the post-glacial carbon cycle as a non-steady state system, where carbon includes the two stable isotopes 12C and 13C, coupled to the nutrient cycles of nitrogen (N) and phosphorus (P), in the four major domains of the Earth's surface system: land, atmosphere, coastal zone, and open ocean (including the sediments of these latter two domains). The project is a collaborative one between the University of Hawaii (Mackenzie) and Northwestern University (Lerman). The work will be based on the modeling approach that the principal investigators developed and used with some success in the study of the coupled carbon-nitrogen-phosphorus-sulfur cycles in the past 300 years, when the system was subjected to human environmental forcings and a rise in temperature. A new model of the four domains and coupled C-N-P biogeochemical cycles for the analysis of the longer period since the LGM (last glacial maximum) to the start of the Industrial Age will include past changes and spatial distributions of 13C (effectively separating the carbon cycle into the 12C and 13C cycles), and modifications of the numbers and structure of the reservoirs within the system, and the kinetic parameters. These fundamental feature changes should allow close approximation of the major changes of the Earth's surface system in that period of time.
