Antarctic Intermediate Water properties since 400 ka recorded in infaunal (Uvigerina peregrina) and epifaunal (Planulina wuellerstorfi) benthic foraminifera

作者：Elmore Aurora C^*; McClymont Erin L; Elderfield Henry; Kender Sev; Cook Michael R; Leng Melanie J; Greaves Mervyn; Misra Sambuddha

来源：Earth and Planetary Science Letters, 2015, 428: 193-203.

DOI：10.1016/j.epsl.2015.07.013

• Antarctic Intermediate Water
• Deep Sea Drilling Program Site 593
• benthic foraminifera
• stable isotopes
• Mg/Ca
• B/Ca

Reconstruction of intermediate water properties is important for understanding feedbacks within the ocean-climate system, particularly since these water masses are capable of driving high-low latitude teleconnections. Nevertheless, information about intermediate water mass evolution through the late Pleistocene remains limited. This paper examines changes in Antarctic Intermediate Water (AAIW), the most extensive intermediate water mass in the modern ocean through the last 400 kyr using the stable isotopic composition (delta O-18 and delta C-13) and trace element concentration (Mg/Ca and B/Ca) of two benthic foraminiferal species from the same samples: epifaunal Planulina wuellerstorfi and infaunal Uvigerina peregrina. Our results confirm that the most reasonable estimates of AAIW temperature and Delta[CO32-] are generated by Mg/Ca-U.peregrina and B/Ca-P.wuellerstorfi, respectively. We present a 400 kyr record of intermediate water temperature and Delta[CO32-] from a sediment core from the Southwest Pacific (DSDP site 593; 40 degrees 30'S, 167 degrees 41'E, 1068 m water depth), which lies within the core of modern AAIW. Our results suggest that a combination of geochemical analyses on both infaunal and epifaunal benthic foraminiferal species yields important information about this critical water mass through the late Pleistocene. When combined with two nearby records of water properties from deeper depths, our data demonstrate that during interglacial stages of the late Pleistocene, AAIW and Circumpolar Deep Water (CPDW) have more similar water mass properties (temperature and delta C-13), while glacial stages are typified by dissimilar properties between AAIW and CPDW in the Southwest Pacific. Our new Delta[CO32-] record shows short time-scale variations, but a lack of coherent glacial-interglacial variability indicating that large quantities of carbon were not stored in intermediate waters during recent glacial periods.

• 出版日期2015-10-15