Ecology. 2014 Apr;95(4):795-800. doi: 10.1890/13-1274.1.
Added Na was used to determine whether litter decomposition and associated fungal biomass and termites are limited by Na availability in a lowland tropical rainforest at Yasuni, Ecuador. This is a partial test of the "sodium ecosystem respiration" (SER) hypothesis that posits Na is critical for consumers but not plants, that Na shortfall is more likely on highly weathered soils inland from oceanic aerosols, and that this shortfall results in decreased decomposer activity. We fertilized 4 x 4 m plots twice a month for a year with quantities of Na comparable to those falling on a coastal tropical rainforest. Decomposition rates of four substrates were consistently higher on +NaCl plots by up to 70% for cellulose, and 78%, 68%, and 29% for three woods of increasing percentage lignin. The density of termite workers averaged 17-fold higher on +NaCl plots; fungal biomass failed to differ. After controlling for temperature and precipitation, which co-limit gross primay productivity (GPP) and ecosystem respiration (ER), these results suggest that Na shortfall is an agent enhancing the storage of coarse woody debris in inland tropical forests.
添加了 Na，以确定在厄瓜多尔亚苏尼的低地热带雨林中， litter 分解以及相关真菌生物量和白蚁是否受到 Na 供应的限制。这是对“钠生态系统呼吸”（SER）假设的部分检验，该假设认为 Na 对消费者很关键，但对植物不重要，在远离海洋气溶胶的内陆高度风化土壤中，Na 短缺更有可能发生，并且这种短缺导致分解者活性降低。我们用与沿海热带雨林相当的数量，每月两次在 4 x 4 m 的实验地块上施肥一年。四种基质的分解速率在+NaCl 实验地块上始终高出 70%，对于纤维素而言高出 78%，对于三种木质素含量逐渐增加的木材而言，分别高出 68%和 29%。+NaCl 实验地块上白蚁工人的密度平均高出 17 倍；真菌生物量没有差异。在控制温度和降水（它们共同限制总初级生产力（GPP）和生态系统呼吸（ER））之后，这些结果表明，Na 短缺是增强内陆热带森林中粗木质残体储存的因素。
