闽江河口互花米草海向入侵对湿地土壤无机硫赋存形态的影响

选择闽江河口鳝鱼滩互花米草海向入侵前的光滩(BF)、入侵过程中(入侵1年)的互花米草湿地(SA′)以及入侵后(入侵3年)的互花米草湿地(SA)为研究对象,基于时空互代法,研究了互花米草海向入侵对湿地土壤无机硫赋存形态(水溶性硫H₂O-S;吸附性硫Adsorbed-S;盐酸可溶性硫HCl-Soluble-S;盐酸挥发性硫HCl-Volatile-S)的影响.结果表明: 互花米草海向入侵不同程度改变了湿地土壤中各形态无机硫的赋存状况及空间分布特征.相对于BF,SA土壤中的H₂O-S、Adsorbed-S和HCl-Volatile-S含量分别增加52.6%、78.2%和21.0%,而HCl-Soluble-S含量降低3.4%.SA′土壤中H₂O-S、Adsorbed-S和HCl-Soluble-S含量相较BF分别增加43.9%、70.6%和29.6%,而HCl-Volatile-S含量降低11.6%.总无机硫(TIS)含量在SA和SA′土壤中较BF分别增加40.7%和37.8%,而储量分别增加26.8%和31.4%.互花米草海向入侵导致影响湿地土壤中不同形态无机硫赋存的关键因素均发生了明显改变.尤其是H₂O-S含量,影响其变化的关键因素由BF的土壤颗粒组成及容重逐步转变为SA′和SA的土壤有机质.研究发现,互花米草海向入侵明显提高了湿地土壤TIS含量,而TIS含量的增加主要取决于H₂O-S和 Adsorbed-S含量的增加,说明互花米草海向入侵明显增加了湿地土壤中有效硫的供给能力,从而在一定程度上加速其海向入侵.

Effects of Spartina alterniflora invasion in a seaward direction on variations of inorganic sulfur forms in marsh soils of the Minjiang River estuary,China

To explore the effects of Spartina alterniflora invasion in a seaward direction on variations of inorganic sulfur forms in marsh soils, the levels of inorganic sulfur forms (H₂O-S, Adsorbed-S, HCl-Soluble-S and HCl-Volatile-S) were determined in bare flat (BF, before invasion), S. alterniflora marsh after seaward invasion for one year (SA′) and S. alterniflora marsh after seaward invasion for three years (SA) in Shanyutan of the Minjiang River estuary with the method of space-for-time substitution. Results showed that the seaward invasion of S. alterniflora altered the stocks and distribution of inorganic sulfur form in marsh soils. Compared with BF, the contents of H₂O-S, Adsorbed-S and HCl-Volatile-S in soils of SA increased by 52.6%, 78.2% and 21.0%, respectively, while that of HCl-Soluble-S decreased by 3.4%. In contrast, the levels of H₂O-S, Adsorbed-S and HCl-Soluble-S in soils of SA′ increased by 43.9%, 70.6% and 29.6%, respectively, whereas that of HCl-Volatile-S decreased by 11.6%. The contents of total inorganic sulfur (TIS) in soils of SA and SA′ increased by 40.7% and 37.8%, while the stocks of TIS increased by 26.8% and 31.4%, respectively. The key factors affecting different forms of inorganic sulfur in marsh soils had changed due to the seaward invasion of S. alterniflora. In particular, the key factors affecting the variations of H₂O-S contents changed from soil grain composition and bulk density in BF to soil organic matter in SA′ and SA. The seaward invasion of S. alterniflora significantly increased the content of TIS in marsh soils, which was mainly contributed by H₂O-S and Adsorbed-S. Thus, it was concluded that the seaward invasion of S. alterniflora significantly increased the supply capacity of available sulfur in marsh soils, which, to some extent, accelerated its seaward invasion.