Superoxide Decay Kinetics in the Southern Ocean.

Heller, Maija and Croot, Peter (2010) Superoxide Decay Kinetics in the Southern Ocean. Environmental Science & Technology, 44 (1). pp. 191-196. DOI 10.1021/es901766r.

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Supplementary data:

Abstract

Measurements of superoxide (O(2)(-)) reaction kinetics were made during a transect with the research icebreaker Polarstern (ANT24-3) in the Antarctic through the Drake Passage in austral autumn 2008. Our sampling strategy was designed to investigate the sinks of superoxide in Polar waters; principally through reactions with dissolved organic matter (DOM) or metals (copper and iron). We modified an existing chemiluminescence flow injection system using methyl Cypridina luciferin analog (MCLA) for the detection of O(2)(-) and added O(2)(-) using KO(2) as the source. Our results indicate that O(2)(-) in ambient seawater had a half-life ranging from 9.3 to 194 s. DTPA additions to seawater, to remove the effects of reactions with metals, revealed O(2)(-) decay rates consistent with a second order reaction, indicating that the dismutation reaction dominated and that reactions with DOM were not significant. Titrations of seawater by the addition of nanomolar amounts of iron or copper revealed the importance of organic chelation of Fe and/or Cu in controlling the reactivity with O(2)(-). Throughout the water column reactions with Cu appeared to be the major sink for superoxide in the Southern Ocean. This new strategy suggests an alternative approach for speciation measurements of Fe and Cu in seawater.

Document Type: Article
Keywords: Marine chemistry; HYDROGEN-PEROXIDE; ANTARCTIC WATERS; PHOTOCHEMICAL PRODUCTION; CHATTONELLA-MARINA; COASTAL WATERS; SURFACE WATERS; NATURAL-WATERS; SEA-WATER; SEAWATER; IRON
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-CH Chemical Oceanography
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1021/es901766r
ISSN: 0013-936X
Projects: Future Ocean
Date Deposited: 15 Oct 2009 15:20
Last Modified: 07 Mar 2017 09:43
URI: http://oceanrep.geomar.de/id/eprint/6153

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