Reduced oxygenation at intermediate depths of the southwest Pacific during the last glacial maximum
| Type | Article | ||||||||||||||||||||
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| Date | 2018-06 | ||||||||||||||||||||
| Language | English | ||||||||||||||||||||
| Author(s) | Durand Axel1, Chase Zanna 1, Noble Taryn L.1, Bostock Helen2, Jaccard Samuel L.3, 4, Townsend Ashley T.5, Bindoff Nathaniel L.1, 6, 7, 8, 10, Neil Helen2, Jacobsen Geraldine9 |
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| Affiliation(s) | 1 : Univ Tasmania, Inst Marine & Antarctic Studies, Hobart, Tas, Australia. 2 : Natl Inst Water & Atmospher Res, Wellington, New Zealand. 3 : Univ Bern, Inst Geol Sci, Bern, Switzerland. 4 : Univ Bern, Oeschger Ctr Climate Change Res, Bern, Switzerland. 5 : Univ Tasmania, Cent Sci Lab, Hobart, Tas, Australia. 6 : Antarctic Climate & Ecosyst Cooperat Res Ctr, Hobart, Tas, Australia. 7 : Marine Atmospher Res, Commonwealth Sci & Ind Res Org, Hobart, Tas, Australia. 8 : Collaborat Australian Weather & Climate Res, Melbourne, Vic, Australia. 9 : Australian Nucl Sci & Technol Org, Lucas Heights, NSW, Australia. 10 : Australian Res Council, Ctr Excellence Climate Syst Sci, Sydney, NSW, Australia. |
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| Source | Earth And Planetary Science Letters (0012-821X) (Elsevier Science Bv), 2018-06 , Vol. 491 , P. 48-57 | ||||||||||||||||||||
| DOI | 10.1016/j.epsl.2018.03.036 | ||||||||||||||||||||
| WOS© Times Cited | 10 | ||||||||||||||||||||
| Keyword(s) | oceanic deoxygenation, redox sensitive elements, ventilation, Antarctic Intermediate Water, New Zealand, circulation changes | ||||||||||||||||||||
| Abstract | To investigate changes in oxygenation at intermediate depths in the southwest Pacific between the Last Glacial Maximum (LGM) and the Holocene, redox sensitive elements uranium and rhenium were measured in 12 sediment cores located on the Campbell and Challenger plateaux offshore from New Zealand. The core sites are currently bathed by Subantarctic Mode Water (SAMW), Antarctic Intermediate Water (AAIW) and Upper Circumpolar Deep Water (UCDW). The sedimentary distributions of authigenic uranium and rhenium reveal reduced oxygen content at intermediate depths (800-1500 m) during the LGM compared to the Holocene. In contrast, data from deeper waters (>= 1500 m) indicate higher oxygen content during the LGM compared to the Holocene. These data, together with variations in benthic foraminiferal delta C-13, are consistent with a shallower AAIW-UCDW boundary over the Campbell Plateau during the LGM. Whilst AAIW continued to bathe the intermediate depths (<= 1500 m) of the Challenger Plateau during the LGM, the data suggest that the AAIW at these core sites contained less oxygen compared to the Holocene. These results are at odds with the general notion that AAIW was better oxygenated and expanded deeper during the LGM due to stronger westerlies and colder temperatures. These findings may be explained by an important change in AAIW formation and circulation. |
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