Improving proxy calibrations in the deep-sea coral Desmophyllum dianthus: nutrients, carbonate ion concentration, and temperatures in past Antarctic Intermediate Waters

• Main Authors: Ko, Stanley, Sherrell, Robert M., Kozdon, Reinhard, Pelejero, Carles, López-Sanz, Àngel, Martínez-Dios, Ariadna, Calvo, Eva María, Bostock, H., Tracey, Di
• Format: Still Image
• Language: unknown
• Published: 2017
• Subjects: Antarctic; New Zealand; Southern Ocean; Antarc*
• Online Access: http://hdl.handle.net/10261/179570

Gordon Research Seminar (GRS) and Gordon Research Conference (GRC), RUTGERS The State University of New Jersey.-- 1 page, 6 figures Changes in the supply of preformed nutrients to the low-latitude thermocline have been implicated as a possible driver of glacial-interglacial CO2variations1. Old, nutrient-rich deep waters are upwelled in the Southern Ocean, advected north and modifiedby biological production, and subsequently subducted to form, Subantarctic Mode Waters (SAMW)and Antarctic Intermediate Waters (AAIW; Fig. 1). These waters supply the low-latitude thermocline with nutrients and may impact biological productivity and the sequestration of atmospheric CO2.Fossil deep-sea corals, Desmophyllum dianthus, around New Zealand offer a unique opportunity to reconstruct the pre-formed nutrient inventory of SAMW and AAIW as they exit the Southern Ocean (Fig. 1). Paleoproxies for nutrients (P/Ca, Ba/Ca)and carbonate ion concentrations (U/Ca) have been field-calibrated in this species2, but with uncertainties. We seek to improve calibrations of these proxies through culturing experiments in controlled seawater conditions, and by refining micromilling and laser-ablation ICPMS (LA-ICPMS) methodologies. Additionally, we are exploring the use of Cd/Ca as an alternative phosphate proxy and Mg/Li as a proxy for temperature Peer Reviewed