Bacterial community composition and function along a river to reservoir transition

Abstract

Bacteria in reservoir systems are controlled by a variety of factors. In this study, a lacustrine system with high primary production fed by a river with lower algal biomass was used to examine the relationship between bacterial community composition (BCC) and function under varying environmental conditions. Bacterial abundance, respiration, production, and growth efficiency were measured in the Cuyahoga River and Lake Rockwell reservoir in Ohio (USA). BCC was determined via terminal restriction length polymorphisms of 16S rRNA genes. Also, in laboratory experiments, bacterial communities were exposed to algal exudates and leaf leachates. Concurrently with physicochemical differences between lacustrine and riverine sites, there were differences in BCC that seemed unrelated to environmental conditions and DOC sources (color: chlorophyll a ratio). Functional attributes varied among dates but not sites, except for bacterial heterotrophic productivity. Overall, the source of DOC differed between the river and reservoir as did BCC. In contrast, bacterial functions, with the exception of productivity, were similar between the river and reservoir sites. Environmental variables (e.g., temperature, nutrient, and chlorophyll a) were correlated with differences in bacterial function. Differences in BCC did not coincide with functional differences in the field or controlled laboratory conditions suggesting that structure and function were uncoupled.

Integrating running water monitoring tools with the Micro Biological Survey (MBS) method to improve water quality assessment

“…The evaluation of physical-chemical parameters confirmed previous studies that showed a relevant influence to a series of factors including inputs from exogenous sources and carbon and nutrient availability on bacteria in river systems [ 29 – 31 ]. The evaluation of the organic load into waters can be extrapolated by using biotic indices, which describe the effects of the increasing organics as a variation of the structure of selected biological assemblages.…”

Nutrients Drive the Structures of Bacterial Communities in Sediments and Surface Waters in the River-Lake System of Poyang Lake

“…It is unequivocal that water and sediment are distinct habitat and harbor distinct bacterial communities. Moreover, lakes and rivers are typically subjected to different environmental conditions, such as flow velocity, water residence time, organic matter quantity and quality, and nutrients content, which can affect the compositions and functions of the microbial community [12,15,29,60]. In our previous study, we demonstrated that bacterial communities in stream biofilms were distinct from downstream lake water in both taxonomic and functional composition [29].…”

“…Lake and river systems have a large contrast in physical and chemical properties [13], leading to different biogeochemical paradigms and further driving the bacterial communities differently in these distinct ecosystems. On the other hands, linkages among aquatic ecosystems are particularly extensive and they provide opportunities in the exchange of materials [14,15]. Rivers receive nutrients and organic matters from the catchment [16][17][18].…”

Picoeukaryotic Diversity and Distribution in the Reservoir Ecological System

“…CJ07 and CJ05 sites are in river-type region, but CJ05 site closer to the reservoir dam. Some studies showed that the hydraulic retention time was a limiting factor of an increase in plankton in reservoir (Mašín et al, 2003;Moitra & Leff, 2015). Therefore, this maybe one reason that the picoeukaryotic communities were significantly different between CJ07 and CJ01 sites but not significant between CJ05 and CJ01 sites.…”