Biotic and geochemical (δ 18 O, δ 13 C, Mg/Ca, Ba/Ca) responses of Globigerinoides ruber morphotypes to upper water column variations during the last deglaciation, Gulf of Mexico

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

“…This serves as a timely com ple ment to re cent field and culture stud ies, in which the po ten tial sig nif i cance of both S and diagenesis on Mg/Ca ra tios is dis cussed (e.g., Kisakürek et al, 2008;Fer gu son et al, 2008;Kontakiotis et al, 2011;Sabbatini et al, 2011;Hönisch et al, 2013;Antonarakou et al, 2015). We pres ent an ex ten sive multi-for mat view (cul ture, core-top and plank ton tow sam ples) of the palaeoceanographically sig nif icant plank tonic foraminifer spe cies Globigerinoides ruber and (sub) spe cies-spe cific (in terms of both col our vari ants and distinct morphotypes in its white chromotype) re sponse to the S and over growth ef fects across a broad range of ocean o graphic re gions in the con text of pub lished cal i bra tion data, high light ing par tic u lar fea tures of each ap proach.…”

“…This issue is par tic u larly rel e vant for ap pli ca tions on the sub spe cies (morphotype) level, which shows dis tinct ecol ogy with dif fer ent bi o log i cal life styles (e.g., hab i tat pref er ences, sea sonal pro duction max ima, strat i fi ca tion, sa lin ity - Numberger et al, 2009;Antonarakou et al, 2015) and pres ents a dif fer ent de gree of response to the diagenetic pro cesses (Antonarakou et al, 2012) re flected both in their sta ble iso tope com po si tions (Kawahata, 2005;Löwemark et al, 2005;Antonarakou et al, 2015) and Mg/Ca geo chem is try (Steinke et al, 2005;Bergami et al, 2008;Antonarakou et al, 2015). Such speciation can com pli cate field-based cal i bra tions be cause of the pos si bil ity of dis tinct spe cies-spe cific re la tion ships, and there fore it is clear that a better un der stand ing of the shell chem is try of the morphotypes is es sen tial for mean ing ful palaeoenvironmental re con structions (Steinhardt et al, 2015;Antonarakou et al, 2015).…”

“…We pres ent an ex ten sive multi-for mat view (cul ture, core-top and plank ton tow sam ples) of the palaeoceanographically sig nif icant plank tonic foraminifer spe cies Globigerinoides ruber and (sub) spe cies-spe cific (in terms of both col our vari ants and distinct morphotypes in its white chromotype) re sponse to the S and over growth ef fects across a broad range of ocean o graphic re gions in the con text of pub lished cal i bra tion data, high light ing par tic u lar fea tures of each ap proach. We es pe cially fo cus on G. ruber since it seems to be the most ap pro pri ate spe cies for the S ef fect due to its con tin u ous pres ence oc cu py ing many overlap ping seg ments of the en tire S range, it is a sen si tive spe cies to ma nip u la tions dur ing cul tur ing ex per i ments (Hemleben et al, 1989;Kisakürek et al, 2008) as well to car bon ate diagenesis in high sa lin ity set tings (Kontakiotis et al, 2011;Boussetta et al, 2011;Sabbatini et al, 2011;Antonarakou et al, 2012), and because it is well in stru men tally val i dated .…”

“…Foraminiferal Mg/Ca ther mom e try is a rap idly de vel op ing and widely used tool for palaeoceanographic re con struc tion (e.g., Lea et al, 2000;Anand et al, 2003;Hoogakker et al, 2009;Kontakiotis et al, 2011;Martínez-Botí et al, 2011;Honisch et al, 2013;Hertzberg and Schmidt, 2013;Lea, 2014;Antonarakou et al, 2015;Spero et al, 2015). The geo chem is try of foraminiferal tests re flects the en vi ron men tal con di tions in which the foraminifera grew and there fore con trib ute in re con struct ing past ocean cli mate.…”

“…The ini tial mile stones, such as the first at tempt to de duce gla cial trop i cal SSTs us ing Mg/Ca (Hastings et al, 1998), the first cal i bra tions made on cul tured whole shells , or the first detailed sed i ment trap cal i bra tions (Anand et al, 2003;Martínez-Botí et al, 2011), was fol lowed by new ones fo cus ing mostly on its con fi dent use on tar geted key (morpho)spe cies (e.g., Globigerinoides ruber) on both short (mod ern or late Quater nary; Steinke et al, 2005;Thirumalai et al, 2014;Antonarakou et al, 2015) and lon ger time scales over the past 17 My (Wara et al, 2005; Me dina-Elizalde and Lea, 2005;Medina-Elizalde et al, 2008;Lear et al, 2015). Es pe cially for the mod ern ma te rial (core-tops, plank ton tows and sed i ment traps), in which the Mg/Ca sig nal is com pli cated by the com bined in fluence of en vi ron men tal pa ram e ters (e.g., sa lin ity, cal cite sat u ration state; Kisakürek et al, 2008;Hoogakker et al, 2009;Kontakiotis et al, 2011;van Raden et al, 2011;Hönisch et al, 2013;Hertzberg and Schmidt, 2013;Hertzberg et al, 2016) and/or bi o log i cal pro cesses (Hathorne et al, 2009;Wit et al, 2010;Bolton et al, 2011;Nehrke et al, 2013;Spero et al, 2015), prog ress has been rapid be cause of im prove ments in an a lyt i cal in stru men ta tion and meth ods (Haley and Klinkhammer, 2002;Benway et al, 2003;Klinkhammer et al, 2004;Rosenthal et al, 2004;Greaves et al, 2008;.…”