Re-evaluation of Redfield Ratios Using OACES and DOE/WOCE/JGOFS CO2 Survey Data
NOAA/DOE OACES, 36 months
PROJECT SUMMARY
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.
Dr. Tsung-Hung Peng
NOAA/AOML
4301 Rickenbacker Causeway
Miami, FL 33149
tel: (305) 361-4380
fax: (305) 361-4392
peng@aoml.noaa.gov
Dr. Jia-Zhong Zhang
NOAA/AOML (CIMAS)
4301 Rickenbacker Causeway
Miami, FL 33149
tel: (303) 361-4397
zhang@aoml.noaa.gov
Dr. Yuan-Hui Li
University of Hawaii
1000 Pope Road
Honolulu, HI 96822
tel: (808) 956-6297
yhli@soest.hawaii.edu