外来种互花米草对盐沼土壤微生物多样性的影响——以江苏滨海为例

研究了江苏滨海外来种互花米草的生长对潮间带土壤微生物特征的影响,结果显示:与原有光滩相比,互花米草的大面积生长,使当地潮间带土壤微生物量增加,并随植被的生长状况发生变化,潮间带土壤微生物对碳和营养物质的利用相对较少;同时微生物生理功能群中占优势的活动组分发生了变化,组成可能更复杂。土壤微生物群落生理功能多样性(CLPP)分析结果显示,潮间带土壤微生物群落对碳源底物的利用能力不高,所利用碳源以糖类、氨基酸类、羧酸类占优势;其中互花米草盐沼微生物利用的碳源种类多于光滩,并且不同季节土壤微生物群落碳源利用类型存在差异;潮间带土壤微生物在不同的季节中其生理功能群组成发生着变化,互花米草盐沼的土壤微生物在植被生长减弱时具有与光滩相近的代谢类群,在生理功能上具有一定的相似性;当植被生长旺盛时,其代谢类群增多,代谢强度升高,微生物群落功能多样性增加。外来种互花米草在滨海潮间带的大面积生长,改善了土壤理化性质,为该处土壤微生物提供了不同的碳源,增强了土壤微生物的活动,改变了土壤微生物群落生理功能结构。

Effects of an alien species (Spartina alterniflora) on soil microorganism diversity in salt marshes,Jiangsu coastal inter-tidal ecosystem

Spartina alterniflora, an introduced species vegetating on inter-tidal flats from the eastern coast of the United States, has become a hot topic focusing on its invasion to local species in the coastal zone of China. Impacts of S. alterniflora to inter-tidal soil microbiological properties and soil microbial diversity in Jiangsu coastland are discussed in the paper by the control of those living in barren tidal flats. The soil microbial biomass in inter-tidal zone increases more with the growth of S. alterniflora comparing with the barren tidal flats, which also indicating seasonal changes with the plant. Less carbon and nutrients are demanded to form the body of soil microorganism in Spartina salt marshes. The community components may be more complicated in Spartina salt marshes with the dominant components activities in microbial physiological function group. Analysis on functions of microbial physiological groups indicates that the carbon utilization of soil microbes is lower at inter-tidal area, which focusing on carbohydrate, amino acid and carboxyl acid as its primary carbon substances and differing with seasonal variety. The soil microbes shows some similarities in physiology with those living in mudflats when Spartina withers in autumn. The function diversity of microbes increases with the vegetation blooming in spring as well as contributing to larger size of microbial population, metabolic activities and composition. S. alterniflora has greatly ameliorated soil characteristics by providing carbon sources, increasing microbe activities and changing its physiological structure when being introduced to Jiangsu coastal inter-tidal zone.