在室内模拟闭光与光照条件,研究长江口滨岸潮滩沉积物-水界面的可溶性硅(SiO3-Si)与无机氮(TIN)通量的变化规律,探讨相关理化因素对其的影响.结果表明:在春夏秋季适合硅藻生长的季节,光照能促进硅藻生长与摄取硅,从而能降低SiO3-Si通量,冬季相反,且二者的效应都不太明显.光照能刺激底栖微生物将NH4^+-N硝化为NOx-N,从而明显降低NH4^+-N通量,且能明显升高NOx-N通量.通过相关分析及数学处理发现,光照影响SiO3-Si通量的温度临界值为20℃;盐度过高会减弱光照对NH4^+-N通量的下降效应;温度过高会减弱光照对NOx-N通量的上升效应.采用趋势线斜率方法判定光照能降低上覆水中ρ(SiO3-Si)/c(TIN)值,光照可能会对底栖微生物群落的结构产生较大影响.
Indoor stimulation flux experiments were used to research the changes in dissolved silicon and inorganic nitrogen flux across the sediment-water interface under dark and light conditions,and the influence of relative physical and chemical factors on flux were discussed.The results showed that: in spring,summer and autumn conditions suitable for growth of diatom,light could stimulate the growth of diatom and accelerate the uptake of dissolved silicon,resulting in a decrease of(SiO3-Si) flux from sediment to overlying water,but in winter neither effect was obvious;and,light could stimulate benthic microorganisms to nitrify(NH4^+-N) to(NOx-N),resulting in a decrease of(NH4^+-N) flux and an increase of(NOx-N) flux from sediment to overlying water.Correlation analysis and mathematics processing showed that: the critical temperature value for the positive/negative impact of light on(SiO3-Si) flux is about(20 ℃);high salinity could weaken the negative impact of light on(NH4^+-N) flux;and,high temperature could weaken the positive impact of light on(NOx-N) flux.Light was determined to decrease the value of(SiO3-Si/TIN) in overlying water by the method of trend slope;therefore, it probably had a large impact on the structure of the benthic microorganism population.