Stream Microbial Community Structured by Trace Elements, Headwater Dispersal, and Large Reservoirs in Sub-Alpine and Urban Ecosystems

Abstract

Stream bacterioplankton communities, a crucial component of aquatic ecosystems and surface water quality, are shaped by environmental selection (i.e., changes in taxa abundance associated with more or less favorable abiotic conditions) and passive dispersal (i.e., organisms’ abundance and distribution is a function of the movement of the water). These processes are a function of hydrologic conditions such as residence time and water chemistry, which are mediated by human infrastructure. To quantify the role of environmental conditions, dispersal, and human infrastructure (dams) on stream bacterioplankton, we measured bacterioplankton community composition in rivers from sub-alpine to urban environments in three watersheds (Utah, United States) across three seasons. Of the 53 environmental parameters measured (including physicochemical parameters, solute concentrations, and catchment characteristics), trace element concentrations explained the most variability in bacterioplankton community composition using Redundancy Analysis ordination. Trace elements may correlate with bacterioplankton due to the commonality in source of water and microorganisms, and/or environmental selection creating more or less favorable conditions for bacteria. Bacterioplankton community diversity decreased downstream along parts of the stream continuum but was disrupted where large reservoirs increased water residence time by orders of magnitude, potentially indicating a shift in the relative importance of environmental selection and dispersal at these sites. Reservoirs also had substantial effects on community composition, dissimilarity (Bray-Curtis distance) and species interactions as indicated by co-occurrence networks. Communities downstream of reservoirs were enriched with anaerobic Sporichthyaceae, methanotrophic Methylococcaceae, and iron-transforming Acidimicrobiales, suggesting alternative metabolic pathways became active in the hypolimnion of large reservoirs. Our results identify that human activity affects river microbial communities, with potential impacts on water quality through modified biogeochemical cycling.

Exploring the Impacts of Full-Scale Distribution System Orthophosphate Corrosion Control Implementation on the Microbial Ecology of Hydrologically Connected Urban Streams

“…Accumulibacter” could be due to the dynamic nature of urban streams ( 52 ). For example, seasonal changes in hydrologic conditions (i.e., stream flow and groundwater table) and environmental parameters can impact necessary (or inhibitory) nutrients for certain organisms ( 53 ), which in turn would impact and shift microbial growth rates. As such, future studies should consider and explore the impacts of seasonal and event based hydrological dynamics on microbial nutrient availability.…”

Connecting thiamine availability to the microbial community composition in Chinook salmon spawning habitats of the Sacramento River basin

“…This observation provides the strongest evidence to date that the HZ is source of dTRCs to the SW, building on previous research from marine and freshwater systems ( 35 , 40 ). Riverine HZs are a major source of microbes and metabolites to the overlying river, and the residence time of the water in the river is directly proportional to the abundance and diversity of both microbes and metabolites ( 73 , 74 ). It is not clear how variations in river flow influence dTRC flux from the sediments but changes in HZ residence time likely influence this process.…”

Temporal dynamics of geothermal microbial communities in Aotearoa-New Zealand

“…With microbial communities in the stream experiencing this disturbance every 30–40 days, we now know resident populations quickly revert back to pre-disturbed states; the previous overflow event to this study ended 8 days prior to sampling ( Supplementary Figure S3 ). Waimangu Stream (~104 l s −1 ) provides a constant reservoir of microbial populations from Frying Pan Lake that can quickly re-colonise downstream sites once the disturbance has ended, thereby providing a short residence time for the disturbed communities ( Jones et al, 2020 ). Frying Pan Lake also undergoes reservoir cycling, albeit less extreme than Inferno Crater Lake ( Scott, 1994 ), which could explain the alternating abundances of both Cyanobacteria and Pseudomonadota observed in all stream sites.…”