Key processes in the coupled carbon, nitrogen, and phosphorus cycling of the Baltic Sea
Key processes in the coupled carbon, nitrogen, and phosphorus cycling of the Baltic Sea
复制标题
波罗的海碳、氮、磷耦合循环的关键过程
作者：
E. Gustafsson;O. Savchuk;B. Gustafsson;Bärbel Müller
在这项研究中，我们研究池的碳（C），氮（N）和磷（P）在波罗的海，模拟和重建的观测。我们进一步量化的C，N和P循环的关键通量。我们的计算包括远洋水库，以及在活跃的沉积层，这使得一个完整的覆盖面的整体C，N和P循环系统规模的存储。C与N和P循环的一个显著特性是，虽然总N和P（TN和TP）的外部供应在很大程度上由内部去除过程平衡，但总碳（TC）供应主要由系统的净输出补偿。换句话说，TN和TP的外部输入，在对比TC，而有效地过滤在波罗的海。此外，有一个净输出的TN和TP的系统，但净输入的溶解无机N和P（DIN和DIP）。相反，TC的有机和无机部分都有净输出。而TC和TP的浮游池主要由无机化合物，TN主要由有机N，因为外来有机N是难降解的。然而，在C、N和P元素比率以及无机与有机组分方面存在较大的流域差异。这些差异反映了外部负荷的不同比例和确定DIN和DIP的氧化还原依赖性通量的不同氧气条件。
In this study we examine pools of carbon (C), nitrogen (N), and phosphorus (P) in the Baltic Sea, both simulated and reconstructed from observations. We further quantify key fluxes in the C, N, and P cycling. Our calculations include pelagic reservoirs as well as the storage in the active sediment layer, which allows a complete coverage of the overall C, N, and P cycling on a system-scale. A striking property of C versus N and P cycling is that while the external supplies of total N and P (TN and TP) are largely balanced by internal removal processes, the total carbon (TC) supply is mainly compensated by a net export out of the system. In other words, external inputs of TN and TP are, in contrast to TC, rather efficiently filtered within the Baltic Sea. Further, there is a net export of TN and TP out of the system, but a net import of dissolved inorganic N and P (DIN and DIP). There is on the contrary a net export of both the organic and inorganic fractions of TC. While the pelagic pools of TC and TP are dominated by inorganic compounds, TN largely consists of organic N because allochthonous organic N is poorly degradable. There are however large basin-wise differences in C, N, and P elemental ratios as well as in inorganic versus organic fractions. These differences reflect both the differing ratios in external loads and differing oxygen conditions determining the redox-dependent fluxes of DIN and DIP.