This research strives to assess the impact of changing land use, nitrate deposition and CO{sub 2} fertilization on soil carbon storage. Our motivation is that this reservoir is the most likely candidate for the so-called missing carbon sink. We are working on several aspects of this problem by measuring carbon content, nitrogen content and radiocarbon ratios in paired soil samples from neighboring sites, to determine the impact of land use on soil carbon inventories and turnover times. We are also gathering information on how the C/N ratios in soils vary with climate and changing land use, in an effort to estimate how much carbon has been sequestered as a result of atmospheric fallout of NH{sub 4}OH and HNO{sub 3}. Finally, we are developing a soil greening model that uses CO{sub 2} growth-enhancement results and bomb radiocarbon-based estimates of soil carbon inventory response times.

This research strives to assess the impact of changing land use, nitrate deposition and CO{sub 2} fertilization on soil carbon storage. Our motivation is that this reservoir is the most likely candidate for the so-called missing carbon sink. We are working on several aspects of this problem by measuring carbon content, nitrogen content and radiocarbon ratios in paired soil samples from neighboring sites, to determine the impact of land use on soil carbon inventories and turnover times. We are also gathering information on how the C/N ratios in soils vary with climate and changing land use, in an effort to estimate how much carbon has been sequestered as a result of atmospheric fallout of NH{sub 4}OH and HNO{sub 3}. Finally, we are developing a soil greening model that uses CO{sub 2} growth-enhancement results and bomb radiocarbon-based estimates of soil carbon inventory response times.

Contamination rates have been estimated for the RTF nitrogen heating and cooling system (NH and CS) due to tritium permeation through the walls of metal hydride vessels. Tritium contamination of the NH and CS will be seen shortly after start-up of the RTF with the majority of it coming from the TCAP units. Contamination rates of the NH and CS are estimated to exceed 400 Ci/year after three years of operation and will elevate tritium concentrations in the NH and CS above 6 {times} 10{sup {minus}3} {mu}Ci/cc. To reduce tritium activity in the NH and CS, a stripper or ``getter`` bed may need to be installed in the NH and CS. Increasing the purge rate of nitrogen from the NH and CS is shown to be an impractical method for reducing tritium activity due to the high purge rates required. Stripping of the NH and CS nitrogen in the glove box stripper system will give a temporary lowering of tritium activity in the NH and CS, but tritium activity will return to its previous level in approximately two weeks.