Rain ratio variation in the Tropical Ocean: Tests with surface sediments in the eastern equatorial Pacific

Glacial deep ocean sequestration of CO2 driven by the eastern equatorial Pacific biologic pump

“…We believe that our CO 3 2− record may provide a better measure of the glacial soft-tissue pump than the biogenic burial records. First, it has been shown that the export flux of POC to the seafloor is not predictive of the concentration of C org in modern surface sediment (Mekik et al, 2007) nor the fraction that is ultimately preserved and buried (Sayles et al, 2001;Mouret et al, 2010;Zonneveld et al, 2010). Furthermore, the Si:C uptake ratio of diatoms is thought to influence frustule architecture (Hutchins and Bruland, 1998;Takeda, 1998) and solubility (Ragueneau et al, 2000), and varies under different environmental conditions (Ragueneau et al, 2006).…”

Southern Ocean biogeochemical impact on the tropical ocean: Stable isotope records from the Pacific for the past 25,000 years

“…Elaboration of the biological pump hypothesis recognized that there were two important additional considerations. The productivity of the oceans must be effectively exported to the deep sea for it to impact climate (climate effect depends on export ratio), and the ratio of organic carbon to calcite rain into the deep sea influences oceanic alkalinity (topic review: ; evidence for rain ratio variation in the modern ocean: Deep Sea Research II volume 54 'The Role of Marine Organic Carbon and Calcite Fluxes in Driving Global Climate Change, Past and Future'; Mekik et al, 2002Mekik et al, , 2007; hence separating productivity into its biogenous export components is important (e.g. Dymond and Lyle, 1985;Archer and Maier-Reimer, 1994;Brzezinski et al, 2002;Matsumoto et al, 2002;Sarmiento et al, 2004).…”

Assessing the reliability of foraminiferal Mg/Ca thermometry by comparing field-samples and culture experiments: a review

“…Mod ern cal i bra tions may be ex pressed by an ex po nen tial re la tion of the form: Mg/Ca = a*exp b*T , where a and b are the pre-ex po nen tial and ex po nen tial con stants, re spec tively. Ad di tion ally, dur ing the last two de cades most re search ers (in both cul ture-and field-based stud ies), in their at tempt to account for the in flu ence of the sec ond ary fac tors that have a disproportionally large in flu ence on Mg/Ca ra tios, pro duced cali bra tion equa tions that in clude, be sides T, a cor rec tion term such as a depth-re lated dis so lu tion ar ti fact (Dekens et al, 2002;Mekik et al, 2007), a sa lin ity cor rec tion fac tor Mathien-Blard and Bassinot, 2009), and a car bon ate ion con tent ( [ ] D CO 3 2 -) cor rec tion, or a com bi na tion of them (Kisakürek et al, 2008;Arbuszewski et al, 2010;Khider et al, 2015). All of these new in sights and ap pli ca tions re in force the view that the max i mum po ten tial of this "palaeothermometer" in re con struct ing past ocean-cli mate in ter ac tions has not yet been reached.…”

“…All three can po ten tially act to off set the orig i nal geo chem is try of foraminiferal tests post-mor tem, ei ther in the wa ter col umn or at be neath the sea-floor (Pearson and Bur gess, 2008;Sadekov et al, 2010). Al though the for mer has been widely stud ied for the Mg/Ca palaeothermometer through wa ter depth transects, size-nor mal ized dis so lu tion prox ies, X-ray to mog ra phy and bulk sedimentological pa ram e ters (e.g., Lea et al, 2000Lea et al, , 2006Dekens et al, 2002;Rosenthal and Lohmann, 2002;Regenberg et al, 2006Regenberg et al, , 2014Fehrenbacher et al, 2006;Mekik et al, 2007;Huang et al, 2008;Mar tin, 2011, 2014;John stone et al, 2011), this is not the case for the other two. Recrystallisation (neomorphism), which re fers to the re place ment of pri mary by new crys tals of the same min eral (cal cite) spe cies (Folk, 1965), is of ten grad ual and very lo calized, which means that many rounds of dis so lu tion and re-precip i ta tion may be ap plied in or der for a new crys tal to be formed, and con se quently it is very dif fi cult to be traced in mod ern ma terial.…”