Global salinization is impacting both terrestrial and freshwater systems. Riparia link these systems and are likely impacted by increased sodium, but impacts are understudied. The sodium ecosystem respiration hypothesis posits that increased sodium under sodium-limitation should stimulate decomposition. We tested this hypothesis in an inland subtropical riparian system by adding 0.067% NaCl every 2 weeks to 1 m² plots (n = 10) or just H₂O (n = 10) and measuring decomposition rates of red maple litter across 9 months. Additionally, we measured leaf sodium content of 4 riparian plant species. Contrary to our predictions, decomposition was 21% slower in sodium addition plots than in controls, but invertebrate decomposer communities did not differ between treatments. Plants had 1.4- to 4-fold higher leaf sodium content after 9 months, but soil sodium content did not differ. This is the first evidence of sodium stress for mesic inland terrestrial ecosystems. Slower decomposition supports the Sodium Subsidy-Stress hypothesis and extends the sodium ecosystem respiration to include sodium-stress impacts on ecosystem functions when sodium occurs in excess of optimal sodium levels. Changes to decomposition and leaf sodium content in riparia demonstrate sodium can impact both green and brown food webs and ultimately affect exchange across terrestrial-aquatic boundaries.

全球盐碱化正在影响陆地和淡水系统。河岸将这些系统联系起来，可能会受到钠增加的影响，但影响尚未得到充分研究。钠生态系统呼吸假说假定在钠限制下增加钠应该刺激分解。我们通过每 2 周向 1 m ²地块 (n = 10) 或仅 H ₂添加 0.067% NaCl 的方式在内陆亚热带河岸系统中测试了这一假设O (n = 10) 并测量 9 个月内红枫凋落物的分解率。此外，我们测量了 4 种河岸植物的叶片钠含量。与我们的预测相反，钠添加地块的分解比对照慢 21%，但无脊椎动物分解群落在处理之间没有差异。9 个月后，植物的叶子钠含量增加了 1.4 到 4 倍，但土壤钠含量没有差异。这是中内陆陆地生态系统钠胁迫的第一个证据。较慢的分解支持钠补贴 - 压力假设，并将钠生态系统呼吸扩展到包括钠超过最佳钠水平时钠压力对生态系统功能的影响。