闽江河口互花米草海向入侵对湿地土壤nirS型反硝化微生物群落结构及多样性的影响

Effects of Spartina alterniflora invasion in a seaward direction on structure and diversity of nir S-type denitrifying microbial community in marsh soils of the Min River estuary

2020年秋季,在闽江河口鳝鱼滩东部的互花米草分布区,由陆向海方向选择互花米草海向入侵前的光滩(MF)、入侵1~2年的互花米草湿地(SAN)和入侵6~7年的互花米草湿地(SA)为研究对象.基于高通量测序技术,探讨了互花米草海向入侵对土壤nir S型反硝化微生物群落结构及多样性的影响.结果表明,变形菌门(Proteobacteria)均是互花米草不同入侵阶段土壤中nir S型反硝化微生物的优势门(90.41%~97.36%),其次是厚壁菌门(Firmicutes)和放线菌门(Actinobacteria),三者在SAN和MF土壤中的丰度均与SA存在显著差异(p<0.05).不同入侵阶段土壤中共有的nir S型反硝化细菌属为假单胞菌属(Pseudomonas)、芽孢杆菌属(Bacillus)、偶氮弧菌属(Azoarcus)、陶厄氏菌属(Thauera)、Sulfurifustis属、副球菌属(Paracoccus)、鲁杰氏菌属(Ruegeria)、红肠命菌属(Rubrivivax)、趋磁螺菌属(Magnetospirillum)和福格斯氏菌属(Vogesella),其中,假单胞菌属是优势菌属(42.08%~54.61%).互花米草海向入侵可使土壤中nir S型反硝化细菌门的数量减少,且多数nir S型反硝化菌属的相对丰度也呈降低变化趋势,这主要与其入侵导致的土壤pH值和粒度组成改变有关.尽管互花米草海向入侵并未显著改变nir S型反硝化微生物群落的多样性,但其显著降低了微生物群落的丰富度(p<0.05).研究发现,互花米草海向入侵主要通过改变湿地土壤的粒度组成、pH值、含水率等理化性质及氮养分条件而影响土壤中nir S型反硝化微生物群落的结构和多样性.

To explore the influences of Spartina alterniflora invasion in a seaward direction on structure and diversity of nir S-type denitrifying microbial community in marsh soils,the mudflat(MF,before invasion),S.alterniflora marsh after seaward invasion for 1~2 years(SAN)and S.alterniflora marsh after seaward invasion for 6~7 years(SA)in Shanyutan of the Min River estuary were investigated in autumn 2020 by the high-throughput sequencing method.Results showed that Proteobacteria was the common predominant phylum of nir S-type denitrifying bacteria in marsh soils of different invasion stages with the relative abundance of 90.41%~97.36%,followed by Firmicutes and Actinobacteria,and their abundance in soils of SAN and MF were significantly different with those of SA(p<0.05).The common genus of nir S-type denitrifying bacteria in marsh soils of different invasion stages were Pseudomonas,Bacillus,Azoarcus,Thauera,Sulfurifustis,Paracoccus,Ruegeria,Rubrivivax,Magnetospirillum and Vogesella,among which the predominant genus was Pseudomonas with the relative abundance of 42.08%~54.61%.As affected by the seaward invasion of S.alterniflora,both the phylum number of nir S-type denitrifying bacteria and the relative abundance of most nir S-type denitrifying bacteria genes declined,which was mainly dependent on the alterations of soil pH and grain composition caused by its invasion.Although the seaward invasion of S.alterniflora did not alter the diversity of nir S-type denitrifying microbial community in marsh soils,the richness of the microbial community decreased significantly(p<0.05).This paper found that the seaward invasion of S.alterniflora altered soil physico-chemical properties(e.g.grain composition,pH,moisture)and nitrogen nutrient conditions,which greatly affected the structure and diversity of nirS-type denitrifying microbial community in marsh soils.