HR: 09:45h
AN: B11B-08    [PDF]
TI: Marine Respiration Ratios
AU: * Broecker, W S
EM: broecker@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W/P.O. Box 1000, Palisades, NY 10964-8000 United States
AU: Takahashi, T
EM: taka@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W/P.O. Box 1000, Palisades, NY 10964-8000 United States
AB: Considerable confusion exists regarding the choice of numerical values for the so-called Redfield ratios. Most often quoted are those determined by Redfield himself O$_{2}$ : C : N : P = 138 : 106 : 16 : 1. He determined these ratios based on the bulk chemical composition of plankton as well as changes in the chemical compositions observed in deep ocean waters. Hence, these ratios represent both the net utilization by plankton in surface waters and the respiration of biogenic debris in deep waters. Only in the mid 1980s did {\it Takahashi and Broecker (1985)} show that the deconvolutions based on nutrient distribution in northern Atlantic employed by Redfield were strongly biased by the admixing of waters from the southern Atlantic thermocline. Based on an analysis of global set, they proposed that an O$_{2}$ to PO$_{4}$ ratio of 176$\pm$6 characterized the entire interior of the major oceans. In the early 1990s, {\it Anderson and Sarmiento (1994)} conducted more elaborate calculations, which confirmed this contention. Recently {\it Li and Peng (2002)} challenged this conclusion claiming that the O$_{2}$ to PO$_{4}$ ratios range from 176 all the way down to 116 with the median value lying close to that proposed by Redfield. If their analysis proves to be correct, it brings into serious question the use of PO$_{4}$$^{*}$ as a quasi-conservative water mass tracer. In this talk, we will strongly defend the validity of the Takahashi- Broecker value. We will also suggest that the term Redfield ratio be restricted to the original 138 : 106 : 16 : 1 values and that the revisions be referred to as respiration ratios.
DE: 1615 Biogeochemical processes (4805)
DE: 4805 Biogeochemical cycles (1615)
DE: 4845 Nutrients and nutrient cycling
SC: Biogeosciences [B]
MN: 2003 Fall Meeting