Using 13C/12C Measurements to Trace the Ocean Carbon Cycle and Anthropogenic CO2 Uptake in the Subtropical Ocean

海洋是人类活动产生的CO2的主要汇，但很少有地点在足够长的时间内定期测量海洋CO2的增加。 在这些时间序列的网站所造成的人为CO2的吸收溶解无机碳（DIC）浓度的增加量化是复杂的DIC预算的自然变异引起的物理强迫和生物生产力的变化。 在夏威夷海洋时间序列（HOTS）网站的13 C/12 C的测量已被证明提供了一个独特的指纹的主要过程影响DIC浓度在海洋表面和一个很好的代理跟踪增加DIC由于吸收人为CO2。 自1995年以来，相对于1990-1995年之间获得的值，DIC（DIC归一化为恒定盐度）的增加率和d13 C-DIC的减少率增加了一倍。 PI建议继续在HOTS研究中心制作13 C/12 C和DIC的月度曲线，以确定加速DIC是否增加，d13 C-DIC是否继续减少。 此外，提议者还将测量HOTS附近地表沃茨DIC和d13 C-DIC的水平梯度，以确定HOTS地表DIC的年际增加在多大程度上可以通过水团平流和生物碳输出速率与人为CO2吸收速率的变化来解释。

ABSTRACTOCE-9911913The ocean is a major sink for CO2 produced by human activities, yet there are few sites where the oceanic CO2 increase is being measured at regular intervals over a long enough time to be detectable. Quantifying the increase in dissolved inorganic carbon (DIC) concentrations at these time series sites caused by uptake of anthropogenic CO2 is complicated by the natural variability in the DIC budget caused by changes in physical forcing and biological productivity. Measurements of 13C/12C at the Hawaii Ocean Time Series (HOTS) site have been shown to provide a unique fingerprint of the primary processes affecting DIC concentrations in the surface ocean and an excellent proxy for tracking the increase in DIC due to uptake of anthropogenic CO2. Since 1995, the rate of increase in DICs (DIC normalized to constant salinity) and decrease in d13C-DIC has doubled relative to values obtained between 1990-1995. The PI proposes to continue making monthly profiles of 13C/12C and DIC at the HOTS site to determine whether the accelerated DICs increase and d13C-DIC decrease continues. In addition, the proponent also will measure the horizontal gradients of DIC and d13C-DIC of surface waters in the vicinity of HOTS to determine how much of the interannual increase in surface DICs at HOTS can be explained by changes in the advection of water masses and rates of biological carbon export versus uptake of anthropogenic CO2.