Xu Jun, Wang Tao, García Molinos Jorge, Li Chao, Hu Bowen, Pan Meng, Zhang Min
Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.
College of Fisheries, Huazhong Agricultural University, Hubei Provincial Engineering Laboratory for Pond Aquaculture, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, PR China.
Environ Int. 2020 Apr;137:105502. doi: 10.1016/j.envint.2020.105502. Epub 2020 Feb 7.
Contemporary evidence suggests that submerged macrophytes are experiencing a global decline due to the multiple compounding anthropogenic stressors impacting shallow lake ecosystems. Eutrophication and climate change are two main widespread, often co-occurring stressors, yet evidence concerning their interactive effects on aquatic plants remains partial and fragmented. Predicting the response of submerged aquatic vegetation to the combined effects of nutrient pollution and compound climate warming (mean + variability) is therefore crucial for the conservation and management of these valuable and vulnerable ecosystems. Here, we present the results of an outdoor mesocosm experiment examining the combined effects of nutrient enrichment (phosphorus addition) and warming (a 4 °C increase in mean temperature above present ambient conditions applied as either a constant increase or a variable increase ranging between 0 and 8 °C to mimic the effect of extreme events but keeping an equivalent total amount of warming) on Potamogeton crispus L. Warming accelerated the growth and senescence of P. crispus suggesting a more important role in maintaining the clear water state in winter-early spring but concomitant to possible earlier turbid states in summer. Warming also consistently advanced the flowering phenology but had no significant effect on flowering duration. There were no significant differences in the life cycle between the two warming treatments, while phosphorus addition also had little effect. However, under phosphorus enrichment, P. crispus increased sexual reproduction investment producing higher seed setting rate per infructescence. In contrast, warming, especially variable warming, may decrease sexual reproduction investment by reducing the number of infructescences. Seed and turion stoichiometry were altered by the combination of warming and phosphorus addition, but the changes were complex and difficult to interpret.
当代证据表明，由于多种叠加的人为压力源影响浅水湖泊生态系统，沉水植物正经历全球范围的衰退。富营养化和气候变化是两个主要的、普遍存在且经常同时出现的压力源，然而关于它们对水生植物的交互作用的证据仍然不完整且零散。因此，预测沉水水生植被对营养物污染和复合气候变暖（平均温度 + 变率）综合影响的响应，对于保护和管理这些珍贵且脆弱的生态系统至关重要。在此，我们展示了一项室外中宇宙实验的结果，该实验研究了营养物富集（添加磷）和变暖（平均温度比当前环境条件升高4°C，以恒定升高或0至8°C之间的可变升高来模拟极端事件的影响，但保持等效的总升温量）对菹草的综合影响。变暖加速了菹草的生长和衰老，这表明在维持冬末至早春的清水状态方面作用更为重要，但同时可能导致夏季更早出现浑浊状态。变暖还持续提前了开花物候，但对开花持续时间没有显著影响。两种变暖处理下的生命周期没有显著差异，添加磷的影响也很小。然而，在磷富集条件下，菹草增加了有性繁殖投入，每个果序产生更高的结实率。相比之下，变暖，尤其是可变变暖，可能会通过减少果序数量来降低有性繁殖投入。变暖与添加磷的组合改变了种子和块茎的化学计量，但变化复杂且难以解释。
