Sus Honjo, Roger Francois, Rick Krishfield and Steve Manganini

Woods Hole Oceanographic Institution, Woods Hole, MA 02543 USA, E-mail: shonjo@whoi.edu

Global export flux and regional functionality of biological pump; A synthesis of JGOFS sediment trap programs since 1982

The algorithms for C_inorg (C in biogenic CaCO₃) and Si_bio export fluxes in >2,000 zones were modeled directly from the sea surface temperature and primary production. Si_bio in the moderate climatic zones with the seasonality was calculated from the sea surface concentration of SiO₂ in winter. Si_bio in the Equatorial Oceans and Arabian Sea was estimated from primary production. Global distribution of the three elements in 250 km-grid was composed and the global fluxes of these elements at 2,000 m were estimated by summing the fluxes representing all individual cells. Our estimates of annual global fluxes of C_org, C_inorg and Si_bio using the data since 1983 are 36.2, 33.8 and 34.6 Tera Moles, respectively. The range of annual global organic carbon is about 0.2 to 25 gC m^-2. Global distribution of annual C_inorg is less variable than the other two criteria and ranges from 0.2 to 10 gC m^-2. The range of annual Si_bio was as wide as 0.5 to >100 gSi m^-2. The global biogeochemical ratios, C_org/C_inorg, Si_bio/C_org and Si_bio/C_inorg are amazingly similar, approximately 1.1, 1.0 and 1.0 in our estimate. Global distribution of C_org/C_inorg ranges from 0.5 to 6, except in a part of the Southern ocean where this value reaches >10. The range of Si_bio/C_inorg is 0.2 to 50 and by far the largest among the above mentioned biogeochemical ratios.