Stable isotopic signature of Southern Ocean deep water CO2 ventilation

Prasanna, K and Ghost, Prosenjit and Kumar, Anil N (2015) Stable isotopic signature of Southern Ocean deep water CO2 ventilation. In: DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY, 118 (B, SI). pp. 177-185.

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Abstract

The link between atmospheric CO2 level and ventilation state of the deep ocean is poorly understood due to the lack of coherent observations on the partitioning of carbon between atmosphere and ocean. In this Southern Ocean study, we have classified the Southern Ocean into different zones based on its hydrological features and have binned the variability in latitudinal air-CO2 concentration and its isotopic ratios. Together with air-CO2, we analysed the surface water for the isotopic ratios in dissolved inorganic carbon (DIC). Using the binary mixing approach on the isotopic ratio of atmospheric CO2 and its concentration, we identified the delta C-13 value of source CO2. The isotopic composition of source CO2 was around -9.22 +/- 0.26 parts per thousand for the year 2011 and 2012, while a composition of -13.49 +/- 4.07 parts per thousand was registered for the year 2013. We used the delta C-13 of DIC to predict the CO2 composition in air under equilibrium and compared our estimates with actual observations. We suggest that the degeneration of the DIC in presence of warm water in the region was the factor responsible for adding the CO2 to the atmosphere above. The place of observation coincides with the zone of high wind speed which promotes the process of CO2 exsolution from sea water. (C) 2015 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Additional Information:	Copy right for this article belongs to the PERGAMON-ELSEVIER SCIENCE LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Keywords:	Southern Ocean; CO2; Deep water ventilation; DIC; delta C-13
Department/Centre:	Division of Mechanical Sciences > Centre for Earth Sciences Division of Mechanical Sciences > Divecha Centre for Climate Change
Date Deposited:	24 Sep 2015 06:25
Last Modified:	24 Sep 2015 06:25
URI:	http://eprints.iisc.ac.in/id/eprint/52455

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