Breadcrumb
• Biochemistry • Biosphere-atmosphere interactions
Bio
Global biogeochemical cycles of nitrogen, carbon and oxygen and their impact on atmospheric trace gases, including nitrous oxide, carbon dioxide and atmospheric potential oxygen
Education
- PhD: Stanford University, 1994
- MS: Stanford University, 1988
- BS: University of California, Berkeley, 1987
Research
My research interests include the global biogeochemical cycles of carbon and nitrogen and their impact on atmospheric trace gases, including atmospheric potential oxygen (APO) and the greenhouse gases nitrous oxide (N2O) and carbon dioxide (CO2). I have performed atmospheric inversions of observed N2O to infer source distributions over North America, finding that N2O emissions are concentrated in agricultural regions, particularly the Midwestern corn/soybean belt. My work shows that these emissions occur mainly in springtime coincident with the application of nitrogen fertilizers. My ongoing research seeks to elucidate the overlap of climatic variability with fertilizer and other agricultural management practices to better understand the human and climatic controls on N2O emissions.
I have also worked on broader issues of carbon-nitrogen cycling, including the control that nitrogen exerts as a limiting nutrient on terrestrial primary production. My research examines how the mineral nitrogen pool is represented in Earth System Models and how that representation affects predictions of nitrogen trace gas emissions, nitrogen leaching and subsequent eutrophication in coastal zones, and CO2 sequestration in the terrestrial biosphere.
I have longstanding interests in ocean biogeochemistry, including quantification of the oceanic N2O source and use of atmospheric trace gases like N2O and APO to quantify oceanic net community production. I have conducted inter-comparisons of the oceanic modules of Earth System Models to evaluate their performance on APO and to assess confidence in future projections of oceanic uptake of atmospheric CO2.
I am also interested in the increasing prevalence among children of inflammatory neurological and immune system disorders, most of which have a strong environmental component. My publications in this field have focused on quantifying the time trend in U.S. autism prevalence, with my most recent work showing that autism prevalence has increased dramatically from near zero in the 1930s to over 1% among children born in 2012.
Finally, I am interested in the intersection of agriculture with human and environmental health, in which the same agricultural practices that lead to greenhouse gas emissions, coastal eutrophication and other environmental damage also contribute to obesity and chronic inflammatory disease in human consumers. In the context of current agricultural priorities that contradict the advice of nutrition and health experts, I am interested in exploring the large-scale issues of climate, biogeochemistry and resource consumption involved in shifting U.S. agriculture toward a greater focus on crops that nourish and support human health.
Publications
For additional publications, see Cynthia's ResearchGate collection (unclaimed).
Systematic assessment of terrestrial biogeochemistry in coupled climate-carbon models
Randerson JT; Hoffman FM; Thornton PE; Mahowald NM; Lindsay K; Lee Y-H; Nevison CD; Doney SC; Bonan G; Stoeckli R...
- Randerson JT
- Hoffman FM
- Thornton PE
- Mahowald NM
- Lindsay K
- Lee Y-H
- Nevison CD
- Doney SC
- Bonan G
- Stoeckli R
Publication Date: 2009-10-01
Type: Journal Article
Contribution of ocean, fossil fuel, land biosphere, and biomass burning carbon fluxes to seasonal and interannual variability in atmospheric CO2
Nevison CD; Mahowald NM; Doney SC; Lima ID; Van der Werf GR; Randerson JT; Baker DF; Kasibhatla P; McKinley GA...
- Nevison CD
- Mahowald NM
- Doney SC
- Lima ID
- Van der Werf GR
- Randerson JT
- Baker DF
- Kasibhatla P
- McKinley GA
Publication Date: 2008-02-12
Type: Journal Article
Impact of variable air-sea O2 and CO2 fluxes on atmospheric potential oxygen (APO) and land-ocean carbon sink partitioning
Publication Date: 2008-01-01
Type: Journal Article
Interannual and seasonal variability in atmospheric N2O
Publication Date: 2007-09-11
Type: Journal Article
Southern Ocean ventilation inferred from seasonal cycles of atmospheric N2O and O2/N2 at Cape Grim, Tasmania
Publication Date: 2005-07-01
Type: Journal Article
Stratospheric influences on the tropospheric seasonal cycles of nitrous oxide and chlorofluorocarbons
Publication Date: 2004-10-21
Type: Journal Article
Quantifying the nitrous oxide source from coastal upwelling
Publication Date: 2004-01-30
Type: Journal Article
Global distribution of N2O and the ΔN2O-AOU yield in the subsurface ocean -: art. no. 1119
Publication Date: 2003-12-18
Type: Journal Article
Coastal upwelling air-sea fluxes revealed in atmospheric observations of O-2/N-2, CO2 and N2O
Publication Date: 2003-03-21
Type: Journal Article
Constraints on N2O sinks inferred from observed tracer correlations in the lower stratosphere
Publication Date: 1999-09-01
Type: Journal Article
Buffering interactions in the modeled response of stratospheric O3 to increased NOx and HOx
Publication Date: 1999-02-20
Type: Journal Article
A reexamination of the impact of anthropogenically fixed nitrogen on atmospheric N2O and the stratospheric O-3 layer
Publication Date: 1997-11-20
Type: Journal Article
Measurements of the NOy - N2O correlation in the lower stratosphere: Latitudinal and seasonal changes and model comparisons
Keim ER; Loewenstein M; Podolske JR; Fahey DW; Gao RS; Woodbridge EL; Wamsley RC; Donnelly SG; DelNegro LA; Nevison CD...
- Keim ER
- Loewenstein M
- Podolske JR
- Fahey DW
- Gao RS
- Woodbridge EL
- Wamsley RC
- Donnelly SG
- DelNegro LA
- Nevison CD
Publication Date: 1997-06-20
Type: Journal Article
Influence of Antarctic denitrification on two-dimensional model NOy/N2O correlations in the lower stratosphere
Nevison CD; Solomon S; Garcia RR; Fahey DW; Keim ER; Loewenstein M; Podolske JR; Gao RS; Wamsley RC; Donnelly SG...
- Nevison CD
- Solomon S
- Garcia RR
- Fahey DW
- Keim ER
- Loewenstein M
- Podolske JR
- Gao RS
- Wamsley RC
- Donnelly SG
Publication Date: 1997-06-20
Type: Journal Article
Model overestimates of NOy in the upper stratosphere
Publication Date: 1997-04-01
Type: Journal Article
In situ observations of NOy, O-3, and the NOy/O-3 ratio in the lower stratosphere
Fahey DW; Donnelly SG; Keim ER; Gao RS; Wamsley RC; DelNegro LA; Woodbridge EL; Proffitt MH; Rosenlof KH; Ko MKW...
- Fahey DW
- Donnelly SG
- Keim ER
- Gao RS
- Wamsley RC
- DelNegro LA
- Woodbridge EL
- Proffitt MH
- Rosenlof KH
- Ko MKW
Publication Date: 1996-06-15
Type: Journal Article
Nighttime formation of N2O5 inferred from the halogen occulatation experiment sunset/sunrise NOx ratios
Publication Date: 1996-03-20
Type: Journal Article
A global model of changing N2O emissions from natural and perturbed soils
Publication Date: 1996-03-01
Type: Journal Article
GLOBAL OCEANIC EMISSIONS OF NITROUS-OXIDE
Publication Date: 1995-08-15
Type: Journal Article