State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Avenue, No. 163, Nanjing, 210023, People's Republic of China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Xianlin Avenue, No. 163, Nanjing, 210023, People's Republic of China.
Environ Pollut. 2020 Jun;261:114220. doi: 10.1016/j.envpol.2020.114220. Epub 2020 Feb 19.
Riparian areas are widely recognized as the main areas for carbon sequestration and nitrogen pollution removal, while little is known about the effects of the respective sand mining activities on riparian zones. In this study, the effects of sand mining activities on the soil organic carbon (SOC) storage, different N-removal processes (Feammox, anammox, and denitrification), and composition of the relative bacterial community at a depth of 0-40 cm were determined based on investigations in riparian sand mining areas and adjacent forestlands. The SOC density of the sand mining areas (2.59 t ha, depth of 0-40 cm) was lower than that of the riparian forestlands (80.42 t ha). Compared with those of the riparian forestland, the sand mining area exhibited a dramatic reduction in the CO-fixed gene abundances (cbbL) and a significant change in the composition of cbbL-containing bacteria. The rates of the Feammox (0.038 ± 0.014 mg N kg d), anammox (0.017 ± 0.017 mg N kg d), and denitrification (0.090 ± 0.1 mg N kg d) processes at a depth of 0-20 cm in the soil layer of the sand mining area were reduced by 70.17%, 91.5%, and 93.62% compared with those of the riparian forestland, respectively. The riparian areas in the study area (approximately 12 ha, depth of 0-40 cm) destroyed by sand mining activities released approximately 933.96 t stored soil carbon, which reduce the annual carbon sequestration potential by 28.8-40.8 t. Moreover, the potential N-removal rates in the riparian forestlands (depth of 0-20 cm) by the Feammox, anammox, and denitrification processes were 1514.21-1530.95 kg N ha year, whereas the potential N-removal rates in the sand mining area were only 121.2-126.19 kg N ha year. Therefore, more investigations are necessary for comparing the benefits and damage of sand mining activities in riparian areas before more sand mining activities are approved.
河岸带地区被广泛认为是碳固存和氮污染去除的主要区域，然而，人们对各自的采砂活动对河岸带的影响知之甚少。本研究通过对河岸带采砂区和相邻林地的调查，确定了采砂活动对 0-40cm 深度土壤有机碳（SOC）储存、不同氮去除过程（Feammox、厌氧氨氧化和反硝化）以及相对细菌群落组成的影响。采砂区（2.59t/ha，0-40cm 深度）的 SOC 密度低于河岸林（80.42t/ha）。与河岸林地相比，采砂区的 CO 固定基因丰度（cbbL）显著降低，cbbL 含菌组成发生显著变化。采砂区 0-20cm 土层中 Feammox（0.038±0.014mgNkgd）、厌氧氨氧化（0.017±0.017mgNkgd）和反硝化（0.090±0.1mgNkgd）的速率分别降低了 70.17%、91.5%和 93.62%。研究区（约 12ha，0-40cm 深度）受采砂活动破坏的河岸带释放了约 933.96t 储存的土壤碳，减少了 28.8-40.8t/a 的年碳固存潜力。此外，河岸林（0-20cm 深度）中 Feammox、厌氧氨氧化和反硝化过程的潜在氮去除速率分别为 1514.21-1530.95kgNha年，而采砂区的潜在氮去除速率仅为 121.2-126.19kgNha年。因此，在批准更多的采砂活动之前，有必要对河岸带采砂活动的效益和危害进行更多的调查比较。
