A global monthly climatology of phosphate, nitrate, and silicate in the upper ocean: Spring‐summer export production and shallow remineralization

Abstract

Abstract. We have created monthly climatologies of nutrients in the upper 500 m of the ocean using the 1998 release of the World Ocean Atlas fiom the Ocean Climate Laboratory at the National Oceanographic Data Center. The data processing is similar to that used by Najjar and Keeling [ 1997] .1 Gt C. The carbon and silica fluxes, considering that they are lower bounds on global export production because they do not capture the production signal in advectively dominated systems, are in reasonable agreement with other lerge scale estimates of organic carbon and silica export. The computed f ratio (using satellite-based estimates of primary production) and the ratio of shallow aphotic zone remineralization to new production tend to increase with increasing latitude, supporting an increase in respiration with temperature, as suggested in recent studies.

Global net community production estimated from the annual cycle of surface water total dissolved inorganic carbon

“…5). The global net community production estimates of 9.1 Ϯ 2.7 and 10.8 Ϯ 2.7 Gt C yr Ϫ1 , henceforth referred to as ''Lee-1'' and ''Lee-2,'' respectively, are in good agreement with the value of 9.4 Gt C yr Ϫ1 determined from the net efflux of biologically produced O 2 (Louanchi and Najjar 2000). Louanchi and Najjar's value has revised Najjar and Keeling's O 2 -based estimate upward by 4-5 Gt C by including the tropics between 20ЊN and 20ЊS and net community production occurring during the cooling season.…”

“…A geochemical approach using seasonal efflux of O 2 across the air-sea interface yields a global net community production of 6.7 Gt C yr Ϫ1 if scaled to a O 2 : C ratio of 1.45 (Louanchi and Najjar 2000). Estimates of net community production using the seasonal drawdown of nitrate (NO ) sions are 4.6 and 5.3 Gt C yr Ϫ1 , respectively (Louanchi and Najjar 2000).…”

“…Seasonally well-sampled pCO 2SW data in this basin provide an additional line of evidence supporting this zonal difference. Takahashi et al (1993) reported that the pCO 2SW in the northwestern North (2000) and with scaled-up estimates of Louanchi and Najjar (2000). Lee-1 and Lee-2 represent global net community production as shown in Figs.…”

Seasonal and inter-annual variability in nutrient supply in relation to mixing in the Bay of Biscay

“…This requires quantification of change from the high nutrient (low oxygen) winter months to the low nutrient (high oxygen) concentrations at the end of spring (Minas & Codispoti, 1993;Louanchi & Najjar, 2000;Southward et al, 2004). In the past the concentrations of nitrate in winter had to be estimated, as direct wintertime measurements were relatively rare (Glover & Brewer, 1998;Koeve, 2001) or assumptions have had to be made on the length of the productive cycle (Waniek et al, 2003).…”

Carbon regeneration in the Cariaco Basin, Venezuela

“…In addition, limiting nutrients for the biota are transported by the upwelling waters to the surface layers and help sustain primary productivity (HUTCHINGS et al, 1994;IANSON, 2003;HUTCHINS, 2013;. The transport of biological material to the ocean's interior is the main driver of the non-zero gradient of many dissolved species in seawater and an important regulator of atmospheric CO 2 on millennial timescales (LOUANCHI;NAJJAR, 2000;SIPPO et al;. In the open ocean, the fluxes of carbon through the water column decease exponentially with water depth due to aerobic respiration by microorganisms (PACE et al, 1987;PACKARD et al, 2015).…”