Dataset: Carbon Survey Redfield Ratios
Deployment: USJGOFS_SMP

Redfield remineralization ratios based on neutral surface analysis of the new global carbon survey data set
Co-Principal Investigator: 
Dr Louis I. Gordon (Oregon State University, OSU-CEOAS)
Dr Nicolas Gruber (University of California-Los Angeles, UCLA)
Dr Robert Key (Princeton University)
Dr Calvin W. Mordy (National Oceanic and Atmospheric Administration, NOAA-PMEL)
Christopher L. Sabine (National Oceanic and Atmospheric Administration, NOAA-PMEL)
BCO-DMO Data Manager: 
Cynthia L. Chandler (Woods Hole Oceanographic Institution, WHOI BCO-DMO)
Version: 
19 July 2002
Version Date: 
2002-07-19
Description

Synthesis of primary nutrients by marine organisms and subsequent remineralization of organic matter is frequently represented by Equation 1

(eq. 1)

where the coefficients are known as the "Redfield" ratios. Redfield ratios have been particularly useful in estimating the utilization of one nutrient from another and in deriving dynamically passive conservative tracers such as "NO" and "PO". More recently PO4*, C* and N* have been used to study air-sea oxygen fluxes, large scale mixing problems, anthropogenic CO2 and nitrogen biogeochemistry. The value of the ratios and their large scale variability are also important because they are a critical component in the application of computer models to study ocean biogeochemistry and global climate change.

The traditional P:N:Corg Redfield ratios of 1:16:106 were based on planktonic decomposition studies. Recent studies have reevaluated the ratios. Significant disagreement still exists, however. In large part the disagreement stems from various weaknesses in the approaches and in the overall quality and quantity of the data sets used.

The goal of this project is to redetermine the Redfield ratios of remineralization. Specific improvements over previous efforts include the availability of a new global high quality nutrient data set and application of an optimal multi-parameter technique to determine endpoints. The technique will be applied on approximately 20 neutral density layers in each ocean basin. A significant improvement over previous work will be the inclusion of the recently completed global CO2 survey results along with the new nutrient data. In the analysis corrections for the potential bias caused by anthropogenic CO2 invasion, nitrogen fixation and denitrification will be made. Preliminary investigations have demonstrated that small systematic offsets exist in the nutrient data.   Therefore, prior to calculation of the Redfield ratios, a comprehensive global calibration of the nitrate, phosphate and silicate data sets will be completed. The analytical procedures for this calibration have already been developed. The results of this work will directly addressspecific research trajectory elements 1 and 2 outlined in the JGOFS SMP implementation plan and will benefit several collaborative efforts.

More information about this dataset deployment