Spatial and Seasonal Analysis of the Physicochemical Properties and Microbial Community Structure in the Water and Soil of Al-Jahra Nature Reserve, Kuwait

Microorganisms make up the foundation of food webs and have critical roles in ecosystem functions. In this study, the microbial community structure of the first artificial freshwater wetland in Kuwait, Al-Jahra Nature Reserve (JNR), is investigated for the first time. The spatial and seasonal variation of the physicochemical characteristics and microbial diversity and abundance of archaeal and bacterial communities in 3 water bodies and 10 soil samples were studied to understand the change in soil type that occurred after the introduction of tertiary treated wastewater to formerly, desert soils for over 30 years. Spatial and seasonal variation in the physicochemical characteristics and the microbial community structure (MCS) was confirmed in the water and soil samples. The diversity and abundance of soil MCS were higher than in the water samples in JNR. Also, bacterial Operational Taxonomic Units (OTUs) were higher than archaeal OTUs in JNR water and soil samples. The freshwater wetland soil in JNR had the highest OTUs and microbial diversity among other soil types with the dominance of Proteobacteria members. The potential key driver in shaping the MCS in JNR samples was soil structure that determines the amount of nutrient, salinity, and moisture that are held in the soil. Although the differences between MCS of JNR water and soil samples were apparent, keystone phyla (i.e., Proteobacteria, Firmicutes, Bacteroidetes, Gemmatimonadetes, Actinobacteria, and Acidobacteria) sequences were present in all the collected samples. The results from this study are essential to understand the transitional soil phases that are created when artificial wetlands are constructed and could be used as a guide to establishing other wetlands in locations with similar physicochemical characteristics.