The decrease in δ¹³C of dissolved inorganic carbon (δ¹³C_DIC) owing to uptake of anthropogenic CO₂ (the oceanic ¹³C Suess effect) in the Southeastern Indian Ocean over the last decade was calculated using an extended multiparameter linear regression technique. Samples collected on the CROCCA‐2S (Coring to Reconstruct Ocean Circulation and Carbon Dioxide Across 2 Seas) cruise in November–December 2018 were compared to samples from the CLIVAR (Climate and Ocean: Variability, Predictability, and Change) and OISO (Océan Indien Service d'Observation) programs from 2007 to 2009. Surface ocean δ¹³C_DIC decreased by an average of −0.53 ± 0.04‰ across this period, at an average rate of −0.053 ± 0.004‰ per year. This rate of δ¹³C_DIC change is an increase from −0.021 ± 0.024‰ per year between 1994 and 2008. We find that the interior water mass most impacted by the oceanic ¹³C Suess effect between 2008 and 2018 was Subantarctic Mode Water (SAMW), within which δ¹³C_DIC decreased by −0.044 ± 0.002‰ per year. Using previously published relationships between the oceanic ¹³C Suess effect and anthropogenic carbon, we estimate the annual storage of anthropogenic carbon within SAMW in the southeastern Indian Ocean has increased from ∼2.0 ± 0.2 μmol/kg per year between 1994 and 2008 to 5.5 ± 0.6 μmol/kg per year between 2008 and 2018.

中文翻译：

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1994年至2018年印度洋东南部大洋13C Suess效应的演变

在δ的减少¹³溶解的无机碳的C（δ ¹³ Ç _DIC由于摄取人为CO的）₂（大洋¹³在过去十年在东南印度洋Ç休斯效果）采用一个扩展多参数线性回归技术来计算。将2018年11月至12月在CROCCA-2S（旨在重建两大海洋中的海洋循环和二氧化碳）航行中收集的样本与CLIVAR（气候和海洋：可变性，可预测性和变化）和OISO（印度洋）的样本进行比较服务D'观察）从2007年到2009年表层海水δ项目¹³ ç _DIC在此期间，平均下降-0.53±0.04‰，每年平均下降-0.053±0.004‰。δ的这个比率¹³ ç _DIC变化是从-0.021±0.024‰的每增加1994年和2008年之间的年我们发现，在海洋影响最大的内陆水体^13个2008年和2018℃之间休斯效果亚南极模态水（SAMW ），其内δ ¹³ C ^ _DIC下降-0.044±0.002‰每年。使用先前发布的关于大洋洲^13的关系C Suess效应和人为碳，我们估计印度洋东南部SAMW内的人为碳年存储量从1994年至2008年的每年约2.0±0.2μmol/ kg增加到2008年至2008年的每年5.5±0.6μmol/ kg 2018。