Synthesis & Modeling Project
Tsung-Hung Peng
Jia-Zhong Zhang
Yuan-Hui Li
Re-evaluation of Redfield ratios using OACES and DOE/WOCE/JGOFS CO2 survey data

NOAA/DOE OACES,  36 months

PROJECT DESCRIPTION: The stoichiometric ratios (or Redfield ratios) of P:N:C:O2 during photosynthesis, respiration, and remineralization processes are fundamental for our understanding biogeochemistry in the ocean.  The separation of anthropogenic CO2 from the large background variability of dissolved inorganic carbon in the ocean in the C* calculation (Gruber et al., 1996) depends on how well we know these stoichiometric ratios.  To improve the estimate of anthropogenic CO2 in the ocean using NOAA/DOE global CO2 survey data, we must first improve the estimates of Redfield ratios by using the available data including those obtained during the NOAA/DOE global CO2 survey cruises.  We propose to re-evaluate the Redfield ratios based on these new data sets by carrying out the new method of two-end-member and three-end-member mixing models of Li et al. (1998) using the vertical profile data set, as well as using the interpolated data to desired isopycnal surfaces corresponding to various depth as in the traditional two-end-member mixing model.  Close collaboration with the Princeton group led by Dr. Key will be maintained.  This group focuses on evaluation of Redfield ratios with the isopycnal two-end-member method.  Results of our estimates will be compared with theirs and both results will be evaluated to obtain the best possible Redfield ratios.  We also propose to analyze NOAA/DOE nutrient data to examine specifically the N/P remineralization ratio and effects of nitrification and denitrification on this ratio in the global oceans.


DATA: Redfield ratios based on WOCE and GEOSECS sections in Atlantic, Indian, and Pacific Oceans, via SMP Data collection.
PUBLICATIONS: Li, Y-H and T-H Peng.  submitted.  Latitudinal change of remineralization ratios in the oceans and its implication for nutrient cycles.
RELATED PROJECTS: Barber; Chai; Dugdale; Wilkerson; Peng "New and export productivity regulation by Si and Fe in the equatorial Pacific Ocean"

Key; Gordon; Sabine; Gruber; Mordy "Determination of the Redfield remineralization ratios based on neutral surface analysis of the new global data set"

Sabine; Key; Feely; Millero; Wanninkhof; Kozyr "Synthesis and interpretation of the NOAA/DOE Global CO2 survey data"


Dr. Tsung-Hung Peng
4301 Rickenbacker Causeway
Miami, FL 33149-1026
tel: (305) 361-4399
fax: (305) 361-4392

Dr. Jia-Zhong Zhang
4301 Rickenbacker Causeway
Miami, FL 33149
tel: (305) 361-4397
tel: (305) 361-4392

Dr. Yuan-Hui Li
University of Hawaii
1000 Pope Road
Honolulu, HI 96822
tel: (808) 956-6297