光照强度对三峡库区消落区土壤-水界面可溶性硅和无机氮释放的影响

Influence of Light Intensity on the Release of Dissolved Silicon and Inorganic Nitrogen from Soils at the Water Fluctuation Zone in the Three Gorges Reservoir Area

通过模拟淹水试验,研究了三峡库区消落区土壤(石灰性紫色土、沉积物、水稻土)可溶性硅和无机氮的释放规律及光照强度的影响.结果表明:光照能加速底栖微生物对NH4+-N的硝化以及摄取,从而使NH4+-N的消耗量增大,含量降低,从而使NO3--N浓度增大,含量升高.光照能刺激上覆水中硅藻的光合作用,加速其生长,使硅藻直接摄取更多的可溶性硅,从而使水体中可溶硅浓度下降.

The influence of light intensity on the release of dissolved silicon and inorganic nitrogen from soils, including a calcareous purple soil, a sediment soil and a paddy soil, in the water fluctuation zone of the Three Gorges Reservoir was investigated by a simulated flooding experiment. The result showed that increasing light intensity could enhance the uptake and nitrification of NH＋-N by benthic microbes, consequently increasing the consumption of NH＋-N and decreasing NH4＋-N concentration, but increasing NO3-N concentration in the overlying water. The increase in light intensity could also promote the photosynthe-sis of diatoms and stimulate their growth, make them directly consume more soluble silica, and decrease the soluble silicon concentration in the overlying water.