Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Sci Total Environ. 2023 Nov 1;897:166190. doi: 10.1016/j.scitotenv.2023.166190. Epub 2023 Aug 9.
Coastal wetlands are undergoing substantial transformations globally as a result of increased human activities. However, compared to other ecosystems, diversity and functional characteristics of microbial communities in reclaimed coastal wetlands are not well studied compared to other ecosystems. This is important because it is known that microorganisms can play a crucial role in biogeochemical cycling within coastal wetland ecosystems. Hence, this study utilized the high-throughput sequencing technique to investigate the structure and assembly processes of microbial communities in reclaimed coastal wetlands. The results revealed a substantial change in soil properties following coastal wetland reclamation. Remarkably, the reclaimed soil exhibited significantly lower pH, soil organic carbon (SOC), and total salinity (TS) values (p < 0.05). The dominant phyla included Proteobacteria, Chloroflexi, Bacteroidetes, Acidobacteria, and Planctomycetes among study sites. However, the relative abundance of Proteobacteria increased from un-reclaimed coastal wetlands to reclaimed ones. The Proteobacteria, Chloroflexi, and Acidobacteria showed higher relative abundance in vegetated soil compared to bare soil, while Bacteroidetes and Planctomycetes exhibited the opposite trend. Notably, vegetation types exerted the strongest influence on microbial diversity, surpassing the effects of soil types and depth (F = 34.49, p < 0.001; F = 25.49, p < 0.001; F = 3.173, p < 0.078, respectively). Stochastic assembly processes dominated in un-reclaimed soil, whereas deterministic processes governed the assembly in artificial sea embankment wetlands (SEW). The presence of Spartina alterniflora in all soil types (except SEW soils) indicated stochastic assembly, while Phragmites australis in reclaimed soils pointed toward deterministic microbial assembly. Furthermore, environmental factors such as pH, soil water content (SWC), SOC, total carbon (TC), total nitrogen (TN), total phosphorus (TP), NH-N, vegetation types, soil depth, and geographic distance exhibited significant effects on microbial beta diversity indices. Co-occurrence network analysis revealed a stronger association between taxa in SEW compared to land reclaimed from wetlands (LRW) and natural coastal wetlands (NCW). The bottom soil layer exhibited more complex network interactions than the topsoil layer. Besides soil parameters, reclamation and varieties of vegetation were also substantial factors influencing the composition, diversity, and assembly processes of microbial communities in coastal wetlands.
沿海湿地由于人类活动的增加而发生了巨大的变化。然而，与其他生态系统相比，受人类活动影响而围垦的滨海湿地中微生物群落的多样性和功能特征仍未得到充分研究。这很重要，因为众所周知，微生物可以在滨海湿地生态系统的生物地球化学循环中发挥关键作用。因此，本研究利用高通量测序技术研究了围垦滨海湿地中微生物群落的结构和组装过程。结果表明，围垦后沿海湿地的土壤性质发生了显著变化。值得注意的是，围垦土壤的 pH 值、土壤有机碳（SOC）和总盐度（TS）显著降低（p<0.05）。在研究地点中，主要的门包括变形菌门、绿弯菌门、拟杆菌门、酸杆菌门和浮霉菌门。然而，与未围垦的滨海湿地相比，围垦土壤中的变形菌门相对丰度增加。与裸土相比，植被土壤中的变形菌门、绿弯菌门和酸杆菌门的相对丰度较高，而拟杆菌门和浮霉菌门则相反。值得注意的是，植被类型对微生物多样性的影响最强，超过了土壤类型和深度的影响（F=34.49，p<0.001；F=25.49，p<0.001；F=3.173，p<0.078）。未围垦土壤中以随机组装过程为主，而人工海堤湿地（SEW）中的组装则以确定性过程为主。除了 SEW 土壤外，所有土壤类型中均存在互花米草（Spartina alterniflora），表明其为随机组装，而开垦土壤中的芦苇（Phragmites australis）则表明微生物为确定性组装。此外，pH 值、土壤含水量（SWC）、SOC、总碳（TC）、总氮（TN）、总磷（TP）、NH-N、植被类型、土壤深度和地理距离等环境因素对微生物β多样性指数有显著影响。共现网络分析显示，SEW 中分类群之间的关联比湿地开垦（LRW）和天然滨海湿地（NCW）中的更为密切。底土层的网络相互作用比表土层更为复杂。除了土壤参数外，开垦和植被种类也是影响滨海湿地微生物群落组成、多样性和组装过程的重要因素。
