Abstract. The Southern Ocean is of global importance and processes such as mesopelagic remineralisation that impact the efficiency of the biological carbon pump in this region is of substantial interest. During this study the proxy barium excess which is utilised to shed light on mesopelagic remineralisation was measured at seven stations along 30° E in the Southern Indian Ocean during early austral winter of 2017. To our knowledge this is the first reported winter study utilising this proxy in the Southern Ocean. Concentrations of 59 to 684 pmol L⁻¹ were comparable to those observed throughout other seasons, indicating that this proxy has a longer timescale than previously thought. Background barium excess values observed in deep waters were also similar to previous studies, not having declined down to an expected true Southern Ocean background value. It is apparent that processes driving the mesopelagic barium excess signal are still underway during early winter. Indicating that continuous remineralisation is sustained at levels comparable to summer, well after bloom termination. Moreover, linking integrated remote sensing primary production to the mesopelagic barium excess signal reiterates a longer timescale. The significant positive correlations obtained in the Antarctic and Subantarctic zones suggest that mesopelagic barium excess stock can be used as a remineralisation proxy on an annual timescale and possible inference of carbon remineralisation from remote sensing data on an annual and basin scale.

中文翻译：

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作为年度再矿化代理，南印度洋冬季初钡过量（GEOTRACES GIPr07巡游）

摘要。南部海洋具有全球重要性，影响该地区生物碳泵效率的诸如中古再矿化等过程引起了人们的极大兴趣。在这项研究中，2017年南极初冬期间，在印度洋南部30°E的七个站点测量了用于解释中古生再矿化的钡过量的代用物。据我们所知，这是首次报道的使用这种代用剂的冬季研究在南大洋。浓度59至684 pmol L ^-1与其他季节观察到的结果可比，表明该代理具有比以前认为的更长的时间范围。在深水中观察到的背景钡过量值也与以前的研究相似，但没有下降到预期的真实值。南部海洋背景值。显然，在初冬期间，驱动中视钡过量信号的过程仍在进行中。表明在矿山终止后很长一段时间内，持续的再矿化作用维持在与夏季相当的水平。此外，将综合遥感初级生产与中视钡过量信号联系起来，可以延长时间范围。在南极和次南极地区获得的显着正相关表明，中古陆钡过量储量可以用作年度时间尺度上的再矿化代用物，并且可以根据年度和流域规模上的遥感数据推断出碳再矿化。