潮间带盐沼植物黏附悬浮颗粒物的差异性研究

Changes of suspended particulates adhering to salt marsh plants

为了研究潮间带盐沼植物黏附悬浮颗粒物的差异性,在长江口选择了三种盐沼植物群落对它们黏附的颗粒物质量进行测定,结果表明：（1）植物群落距潮沟或光滩越近,生长位置的滩面高程越低,则黏附颗粒物越多,而在盐沼前缘单位滩地面积上植物黏附颗粒物的质量以1%~3%/m（单位水平距离）的速率从水体悬浮颗粒物含量相对较高的盐沼外缘光滩或潮沟向盐沼内部减小;（2）植物黏附的颗粒物量在垂向上从上到下急剧增大,通常在靠近滩面5~10 cm的部分植物的黏附量占植物黏附总量的三分之一以上;（3）相邻群落单位滩地面积的互花米草[（220.6±172.7）g/m2]的总黏附量明显多于芦苇[（64.9±38.1）g/m2]和海三棱藨草[（45.2±31.7）g/m2],而按单位生物量来说单位滩地面积上三种盐沼植物黏附的颗粒物以海三棱藨草最多[（150.5±134.8）g/kg],芦苇最少[（28.8±22.8）g/kg],互花米草介于两者之间[（57.5±32.9）g/kg];（4）海三棱藨草的黏附量在季节上差异性明显,秋初（9月）是春末（5月）的6倍,在冬季该植物消失,其黏附颗粒物的功能也消失。造成盐沼植物黏附悬浮颗粒物差异的根本原因是生物量、悬浮颗粒物含量和淹没条件（淹没的深度、时间、频率）的不同。

To understand the difference of suspended particulates adhering to tidal marsh plants,the mass of particulates adhering to three species of marsh plants was measured in the Changjiang Delta.The results are as follows：（1） The mass of suspended particulates adhering to plants growing on unit land area decreases at a rate of 1%~3%/m with distance from outer marsh edge or tidal creak where a suspended sediment content is higher;（2） the mass of suspended particulates adhering to plants decreases from the lowest stem section upward to the end of plants,and the mass of suspended particulates adhering to the lowest 5~10 cm stem of distance from marsh surface is more than one third of the total;（3）the mass of suspended particulates adhering to Spartina alterniflora [（220.6±172.7） g/m2] is greater than the mass of suspended particulates adhering to Phragmites australis [（64.9±38.1） g/m2] and Scirpus mariqueter [（31.6±10.0） g/m2],because the biomass of S.alterniflora is greater than the biomass of P.australis and S.mariqueter,however,the mass of suspended particulates adhering plants for unit plant biomass is the highest for S.mariqueter [（150.5±134.8） g/kg] and the lowest for P.australis [（28.8±22.8） g/kg],and between the above-mentioned two for S.alterniflora [（57.5±32.9） g/kg];（4） the seasonal change in mass of suspended particulates adhering to marsh plants can be significant.The mass of suspended particulates adhering to S.mariqueter in September was six times more than that in May.In winter,this pioneer plant withered and was washed away by tidal water,and thereby lost its ability to trap suspended particulates.It was concluded that the mass of suspended particulates adhering to marsh plants is determined by the plant biomass,the suspended particulate content and submerged conditions（the relative importance of elevation and tidal range）.