Allen, Katherine A.Hoenisch, BaerbelEggins, StephenRosenthal, Y2015-12-100012-821Xhttp://hdl.handle.net/1885/66544The ratio of boron to calcium (B/Ca) in the calcite tests of planktic foraminifers may serve as a proxy for past seawater chemistry, but controls on B incorporation are not yet certain. Here we present the results of laboratory culture experiments with live specimens of Globigerinoides ruber (pink) and Globigerinoides sacculifer, which provide new insight into B incorporation controls. We find that in G. sacculifer, B/Ca increases with increasing pH (lower [HCO 3-], higher [CO 32-] and [B(OH) 4-]), but decreases with increasing total dissolved inorganic carbon (DIC) (higher [HCO 3-] and [CO 32-], constant [B(OH) 4-]). This suggests competition between aqueous boron and carbon species for inclusion into the calcite lattice. Similar to previous experiments with the subtropical-temperate Orbulina universa, B/Ca increases with salinity, but not with temperature. We evaluate possible carbonate system control parameters, and compare our tropical culture calibrations with new and published core-top data.Keywords: B incorporation; Carbon species; Carbonate system; Dissolved inorganic carbon; Environmental control; Foraminifera; Foraminifers; Planktic foraminifera; Puerto Rico; Seawater chemistry; Boron; Experiments; Seawater; Tropics; Calcite; boron; calcite; calci B/Ca; Boron; Foraminifera; Puerto Rico; Seawater carbonate chemistry; Seawater pH201210.1016/j.epsl.2012.07.0042016-02-24