Engineering Papers⌕ Search

Engineering topics

Anderson, I. C.

Publications and source records attributed to Anderson, I. C..

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Relative rates of nitric oxide and nitrous oxide production by nitrifiers, denitrifiers, and nitrate respirers

An account is given of the atmospheric chemical and photochemical effects of biogenic nitric and nitrous oxide emissions. The magnitude of the biogenic emission of NO is noted to remain uncertain. Possible soil sources of NO and N2O encompass nitrification by autotropic and heterotropic nitrifiers, denitrification by nitrifiers and denitrifiers, nitrate respiration by fermenters, and chemodenitrification. Oxygen availability is the primary determinant of these organisms' relative rates of activity. The characteristics of this major influence are presently investigated in light of the effect of oxygen partial pressure on NO and N2O production by a wide variety of common soil-nitrifying, denitrifying, and nitrate-respiring bacteria under laboratory conditions. The results obtained indicate that aerobic soils are primary sources only when there is sufficient moisture to furnish anaerobic microsites for denitrification.

Anderson, I. C.↗
NASA NTRS1984

Tropospheric sources of NO(x) - Lightning and biology

Laboratory tests were performed to quantify the expected NO(x) production by lightning and biological processes. Attention was focused on energy deposition by lightning and the oxygen partial pressure of soil, and one-dimensional photochemical models were defined for the tropospheric distributions of NO and HNO3 for various NO source strengths. The Lightning Facility data were compared with air samples of N2O production gathered during over 2 yr of flights through storms. Soil NO(x) productions were studied in terms of nitrification processes involving Nitrosomonas europaea and Alcaligenes faecalis bacteria, which change ammonium to nitrite and release NO and N2O as byproducts. The results indicate that atmospheric NO(x) is generated at two tropospheric levels, with lightning and soil bacteria being significant contributors.

Levine, J. S.↗
NASA NTRS1984

Tropospheric sources of NOx: lightning and biology

Laboratory experiments to quantify the global production of NOx (NO + NO2) in the troposphere due to atmospheric lightning and biogenic activity in soil are presented. These laboratory experiments, as well as other studies, suggest that the global production of NOx by lightning probably ranges between 2 and 20 MT(N)y-1 of NO and is strongly dependent on the total energy deposited by lightning, a quantity not well-known. In our laboratory experiments, nitrifying micro-organisms is soil were found to be a significant source of both NO and nitrous oxide (N2O). The measured production ratio of NO to N2O averaged 2-3 for oxygen partial pressures of 0.5-10%. Extrapolating these laboratory measurements to the global scale, which is somewhat risky, suggests that nitrifying micro-organisms in soil may account for as much as 10 MT(N) y-1 of NO. Additional experiments with denitrifying micro-organisms gave an NO to N2O production ratio ranging from 2 to 4 for an oxygen partial pressure of 0.5% and a ratio of less than unity for oxygen partial pressures ranging from 1 to 20%. The production of NO and N2O, normalized with respect to micro-organism number indicates that the production of both NO and N2O by denitrifying micro-organisms is at least an order of magnitude less than production by nitrifying micro-organisms for the micro-organisms studied.

Atmosphere/chemistry↗