Spatio-temporal dynamics of bacterial communities in the shoreline of Laurentian great Lake Erie and Lake St. Clair’s large freshwater ecosystems

Abstract

Background Long-term trends in freshwater bacterial community composition (BCC) and dynamics are not yet well characterized, particularly in large lake ecosystems. We addressed this gap by temporally (15 months) and spatially (6 sampling locations) characterizing BCC variation in lakes Erie and St. Clair; two connected ecosystems in the Laurentian Great Lakes. Results We found a spatial variation of the BCC between the two lakes and among the sampling locations (significant changes in the relative abundance of 16% of the identified OTUs at the sampling location level). We observed five distinct temporal clusters (UPGMA broad-scale temporal variation) corresponding to seasonal variation over the 15 months of sampling. Temporal variation among months was high, with significant variation in the relative abundance of 69% of the OTUs. We identified significant differences in taxonomic composition between summer months of 2016 and 2017, with a corresponding significant reduction in the diversity of BCC in summer 2017. Conclusions As bacteria play a key role in biogeochemical cycling, and hence in healthy ecosystem function our study defines the scope for temporal and spatial variation in large lake ecosystems. Our data also show that freshwater BCC could serve as an effective proxy and monitoring tool to access large lake health.

Aquatic Bacterial Community Connectivity: The Effect of Hydrological Flow on Community Diversity and Composition

“…We observed substantial variation in bacterial community composition but not diversity among the three sampled locations (LR, DR, and LE). While the pattern of location effects was consistent with our predictions based on hydrological differences, the three sampled locations likely also differed in other biotic and abiotic factors [5]. However, our reported patterns of community divergence are not likely due to spatial distance effects alone, as the three locations were separated by a maximum of 50 km and are connected as part of the Huron-Erie corridor [40].…”

“…Many factors contribute to the variation observed in aquatic bacterial community composition among sites and ecosystems [4]. Bacterial communities can be very specialized, with high levels of spatial and temporal variation, where significant differences can be found even a few meters apart in the water column [5]. While the factors driving bacterial community variation are not always resolved, they generally include both biotic and abiotic factors [4,6].…”

Temporal patterns of bacterial communities in the Billings Reservoir system

“…For example, as expected, water surface temperature, an important abiotic factor affecting aquatic microbial communities, was on average 4.70 °C warmer during the summer months than during the winter months. A temperature fluctuation of this magnitude can greatly accelerate the growth rates of cyanobacteria and mesophilic bacteria 61 – 63 . Seasonal changes in temperature have also been reported as the principal factor driving alterations of the bacterial populations in freshwater Lake Taihu 64 and in Pearl River Estuary sediments 65 .…”

Effects of drought-induced stress on nematode communities in aquatic and terrestrial habitats of the Nebraska Sandhills

“…As one of the most disregarded habitat types in community ecology, there are no other studies of nematodes in terrestrial-aquatic transitional zones to compare these results. However, there is evidence of functional changes in shoreline microbial communities as water levels change over time (Shahraki et al, 2021). As discussed previously, with strong ties between nematode and microbial communities, it is imperative to define how the dual impact of change in nematode community composition and microbial community functioning will impact this habitat in the future, specifically regarding decomposition.…”