Instituto Português do Mar e da Atmosfera (IPMA), I. P., Av. Brasília, 1449-006, Lisbon, Portugal.
Instituto Superior de Educação e Ciências de Lisboa (ISEC Lisboa), Lisbon, Portugal.
Sci Rep. 2017 Aug 7;7(1):7376. doi: 10.1038/s41598-017-06758-z.
Ten field cruises were carried out in Tagus estuary from 1999 to 2007 to study the dynamics of the inorganic carbon system. Dissolved inorganic carbon (DIC) and total alkalinity (TA) increased with salinity. DIC and TA were generally conservative in the estuarine mixing zone (salinity > 10), while a complex distribution pattern was observed at the upper estuary. DIC values peaked 1786.9 ± 155.8 µmol kg at that segment. Estimated annual mean fluxes of DIC were 0.27 Tg C yr from the river to the estuary, and 0.37 Tg C yr from here to the coastal area. The Tagus estuary was always CO supersaturated, with partial pressure of CO (pCO) reaching 9160 µatm in the upper estuary. An average emission of 0.11 Tg C yr was estimated from the estuary to the atmosphere, corresponding to 23% of exported DIC. Only 8% of the riverine DIC was ventilated. The non-conservative behaviour of CO parameters in the estuary segment under freshwater influence was attributed to alternations in the relevance of riverine/terrestrial runoff, photosynthesis, aerobic respiration, organic matter mineralization and CaCO precipitation/dissolution.
从 1999 年到 2007 年，在塔霍河口进行了十次野外巡航，以研究无机碳系统的动力学。溶解无机碳（DIC）和总碱度（TA）随盐度增加而增加。在河口混合区（盐度>10），DIC 和 TA 通常是保守的，而在上游河口则观察到复杂的分布模式。在该段，DIC 值达到 1786.9±155.8 µmol kg 的峰值。估计 DIC 的年平均通量为 0.27 Tg C yr 从河流到河口，0.37 Tg C yr 从这里到沿海地区。塔霍河口始终处于 CO 过饱和状态，在上游河口，CO 的分压（pCO）达到 9160 µatm。从河口到大气的估计排放量为 0.11 Tg C yr，相当于出口 DIC 的 23%。只有 8%的河流 DIC 被通风。在淡水影响下的河口段 CO 参数的非保守行为归因于河川/陆地径流量、光合作用、需氧呼吸、有机质矿化和 CaCO3 沉淀/溶解的相关性的交替变化。
