Dissolved organic matter cycling in the confluence of the Atlantic and Indian oceans south of Africa

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• 作者：E. Guerrero-Feij贸o ; M. Nieto-Cid ; M. 脕lvarez ; X.A. 脕lvarez-Salgado
• 关键词：AAIW ; Antarctic Intermediate Water ; AAIW3 ; Antarctic Intermediate Water of 3  ; ° ; C ; AAIW5 ; Antarctic Intermediate Water of 5  ; ° ; C ; AC ; Agulhas Current ; ACC ; Antarctic Circumpolar Current ; AOU ; Apparent oxygen utilization ; CDW ; Circumpolar Deep Water ; DOC ; Dissolved Organic Carbon ; DWBC ; Deep Western Boundary Current ; GH04 ; GoodHope hydrographic line 2004 ; ICW ; Indian Central Water ; ICW13 ; ICW of 13  ; ° ; C ; ICW16.5 ; ICW of 16.5  ; ° ; C ; LAT ; Latitude ; LON ; Longitude ; MOC ; Me
• 刊名：Deep Sea Research Part I: Oceanographic Research Papers
• 出版年：January, 2014
• 年：2014
• 卷：83
• 期：Complete
• 页码：12-23
• 全文大小：5351 K

文摘

The boundary between the Atlantic and Indian sectors of the Southern Ocean is a key spot of the thermohaline circulation, where the following water masses mix up: Indian Central water (ICW), South Atlantic Central Water (SACW), Antarctic Intermediate Water (AAIW), Circumpolar Deep Water (CDW), North Atlantic Deep Water (NADW), Weddell Sea Deep Water (WSDW) and Antarctic Winter Water (WW). An optimum multiparameter analysis based on the distributions of potential temperature, salinity, NO (=O₂+9.3脳NO₃) and silicate during the GoodHope 2004 (GH04) cruise allowed us to (i) define the realms of these water masses; (ii) obtain the water mass proportion weighted-average (archetypal) apparent oxygen utilization (AOU) and dissolved organic carbon (DOC) concentrations of each water mass; and (iii) estimate the contribution of DOC to the oxygen demand of the study area. WW represented only 5.2% of the water volume sampled during GH04, followed by WSDW with 10.8%, NADW with 12.7%, SACW with 15.3%, AAIW with 23.1% and CDW with 32.8%. The distributions of DOC and AOU were mainly explained by the mixing of archetypal concentrations of these variables, 75卤5% and 65卤3% respectively, which retained the variability due to the basin-scale mineralization from the formation area to the barycentre of each water mass along the GH04 line. DOC accounted for 26卤2% and 12卤5% of the oxygen demand of the meso- and bathypelagic ocean, respectively. Conversely, local mineralization processes, retained by the residuals of the archetypal concentrations of DOC and AOU, did not contribute to improve significantly the mixing model of DOC.