The impact of marginal ice zone processes on the distribution of 21OPb, 21OPo and 234Th and implications for new production in the Bellingshausen Sea, Antarctica

Global database of surface ocean particulate organic carbon export fluxes diagnosed from the <sup>234</sup>Th technique

“…The few studies that have examined the discrepancy between 234 Th-derived estimates and direct measurements of POC export (e.g. Le Moigne et al, 2013;Stewart et al, 2007) suggest that 234 Th-derived estimates in most cases overestimate the direct POC flux. This may be due to a mismatch in timescales over which different methods estimate export.…”

Particle-reactive radionuclides (<sup>234</sup>Th, <sup>210</sup>Pb, <sup>210</sup>) as tracers for the estimation of export production in the South China Sea

“…Wei andMurray (1991, 1994) compared the geochemical behavior of 234 Th, 210 Pb, and 210 Po in the Black Sea. Shimmield et al (1995) measured the three radionuclides from the same seawater samples collected in the upper 500 m from the marginal ice zone in the Antarctica. Kim and Church (2001) presented dissolved and particulate 234 Th, 210 Pb, and 210 Po data determined on the same samples collected from the Sargasso Sea.…”

“…POC flux) from the euphotic layer of the ocean (Buesseler et al, 2006 and refereces therein). For the same purpose, 210 Pb and 210 Po, as additional tracers, were used to constrain the determination of the export production in the euphotic layer (Shimmield et al, 1995;Stewart et al, 2007;Murray et al, 2005;Friedrich and Rutgers van der Loeff, 2002;Kim and Church, 2001;Buesseler et al, 2008). In the context of treating particle-reactive radionuclides as proxies for POC flux, export production or sinking flux of PIC and PN from the euphotic layer can also be estimated by multiplying the flux of radionuclides, which is obtained from the mass balance of daughter radionuclide relative to its parent radionuclide in the euphotic layer, by the ratio of POC (or PIC, PN) and radionuclide in sinking (or sinkable) particles (Murray et al, Buesseler, 1998;Bacon et al, 1996), i.e.…”

The influence of particle concentration and composition on the fractionation of 210Po and 210Pb along the North Atlantic GEOTRACES transect GA03

“…The disequilibrium 40 between 210 Po and 210 Pb has been used in many studies to determine particle export from the 41 upper ocean (e.g. Buesseler et al, 2008;Friedrich and Rutgers van der Loeff, 2002;Murray 42 et al, 2005;Shimmield et al, 1995;Stewart et al, 2007a;Verdeny et al, 2008), in a similar 43 application to the more commonly used 234 Th/ 238 U system (e.g. Buesseler et al, 1992; 44 Charette et al, 2001;Cochran, 2003).…”