Ecogenomics Reveals Metals and Land-Use Pressures on Microbial Communities in the Waterways of a Megacity

Abstract

Networks of engineered waterways are critical in meeting the growing water demands in megacities. To capture and treat rainwater in an energy-efficient manner, approaches can be developed for such networks that use ecological services from microbial communities. Traditionally, engineered waterways were regarded as homogeneous systems with little responsiveness of ecological communities and ensuing processes. This study provides ecogenomics-derived key information to explain the complexity of urban aquatic ecosystems in well-managed watersheds with densely interspersed land-use patterns. Overall, sedimentary microbial communities had higher richness and evenness compared to the suspended communities in water phase. On the basis of PERMANOVA analysis, variation in structure and functions of microbial communities over space within same land-use type was not significant. In contrast, this difference was significant between different land-use types, which had similar chemical profiles. Of the 36 environmental parameters from spatial analysis, only three metals, namely potassium, copper and aluminum significantly explained between 7% and 11% of the variation in taxa and functions, based on distance-based linear models (DistLM). The ecogenomics approach adopted here allows the identification of key drivers of microbial communities and their functions at watershed-scale. These findings can be used to enhance microbial services, which are critical to develop ecologically friendly waterways in rapidly urbanizing environments.

Integrative systems approach reveals dynamics of microbiome-metal-ion axis in mesocosms representing tropical urban freshwater canal ecosystem

“…The functional genes that encoded for the pathways of photosynthesis and nitrogen metabolism were largely mapped to the members of cyanobacteria ( Figure 5). Their higher abundance in the industrial land use compared with the residential land use is in agreement with a previous study 5 and is related to the lower levels of antibiotics in industrial areas 1 . The heterotrophic ecological group in this phase was mostly dominated by proteobacteria, which encoded functional genes for alternate sources of carbon, such as the products of organic degradation.…”

“…Tropical urban canal systems (TrUCS) are unique and dynamic ecosystems, driven by both natural and anthropogenic controlling factors that can influence both top-down effects, such macro-ecological bioturbation and predation, and bottom-up effects, such as nutrients transformation on the microbial ecosystem. The complex sedimentary microbial communities (SedMIC) in TrUCS ecosystems with inherent self-cleaning potential are shaped by these factors these factors 1,2 . Yet, the interactions between microbial communities and the ecosystem controlling factors at a systems level are poorly understood.…”

“…The constant release of land-use-specific stressors through basal flow of water exerts a chronic anthropogenic (press) disturbance in the sedimentary ecosystems of TrUCS 1 from different land use types. For example, while organics enter the canal ecosystem mainly via increased sediment flow, the water-soluble components, such as nutrients, enter the canals through the water phase 1 . A diverse pool of metals entering the TruCS has the potential to influence the functioning of microbial communities 1 , specifically, in assisting the energy harvest processes.…”

“…Nutrient transformations, on the other hand, can have a profound effect on primary productivity and heterotrophic processes in TrUCS. The involvement of metals such as aluminum in shaping the functions of SedMICs 1,6 indicates the presence of novel interactions and associations of environmental constituents with energy and nutritional pathways. The outcome of these interactions might have a direct effect on surface water quality.…”

The Relationship between pH and Bacterial Communities in a Single Karst Ecosystem and Its Implication for Soil Acidification

“…Potassium, which can affect the functions of transporters through controlling the cytosolic ionic strength (Saxena et al, 2015), can also affect microbial community diversity and composition (Mendes et al, 2014; Pereira et al, 2014; Stroobants et al, 2014; Archer et al, 2015; Li et al, 2015; Saxena et al, 2015). K + and pH correlated to specific taxonomic groups, such as Bacillus and Pseudomonas , in the cave sediments and drip waters, respectively ( Figure 7 ), and these bacteria may play a dominant role in releasing potassium into the environment during pH changes within the karst system (Hu et al, 2006; Mendes et al, 2014).…”