The Role of Environmental Processes and Geographic Distance in Regulating Local and Regionally Abundant and Rare Bacterioplankton in Lakes

Abstract

Bacteria are vital components of lake systems, driving a variety of biogeochemical cycles and ecosystem services. Bacterial communities have been shown to have a skewed distribution with a few abundant species and a large number of rare species. The contribution of environmental processes or geographic distance in structuring these components is uncertain. The discrete nature of lakes provides an ideal test case to investigate microbial biogeographical patterns. In the present study, we used 16S rRNA gene metabarcoding to examine the distribution patterns on local and regional scales of abundant and rare planktonic bacteria across 167 New Zealand lakes covering broad environmental gradients. Only a few amplicon sequence variants (ASVs) were abundant with a higher proportion of rare ASVs. The proportion of locally abundant ASVs was negatively correlated with the percentage of high productivity grassland in the catchment and positively with altitude. Regionally rare ASVs had a restricted distribution and were only found in one or a few lakes. In general, regionally abundant ASVs had higher occupancy rates, although there were some with restricted occupancy. Environmental processes made a higher contribution to structuring the regionally abundant community, while geographic distances were more important for regionally rare ASVs. A better understanding of the processes structuring the abundance and distribution of bacterial communities within lakes will assist in understand microbial biogeography and in predicting how these communities might shift with environmental change.

Deterministic processes drive national‐scale patterns in lake surface sediment bacteria and eukaryotic assemblage composition

“…Positive abundance–occupancy relationships have been noted for a wide range of taxa from bacteria to vertebrates (Shade et al 2018). The results presented here suggest that both the bacterial and eukaryotic assemblages in the surface sediments of lakes on a national scale follow the same pattern, a trend also observed for the bacterioplankton in a subset of these lakes (Pearman et al 2022 a ). The majority of the taxa found in this study where present only in one lake and had very low relative abundances.…”

“…However, even within reasonably short geographic distances they can experience diverse environmental conditions due to differences in parameters such as size, depth, geomorphology, and land use and geology in their catchment. The plankton communities of lakes have been extensively studied (Kraemer et al 2020; Schallenberg et al 2021; Pearman et al 2022a). Work involving sediments, has generally focused on paleolimnological studies, involving taxa that fossilize such as diatoms (Rühland et al 2003) and chironomids (Irvine et al 2012), although molecular approaches to assess other taxa are increasing (Capo et al 2022).…”

Human access and deterministic processes play a major role in structuring planktonic and sedimentary bacterial and eukaryotic communities in lakes

“…The planktonic bacterial (Pbact) community had high proportions of Sporichthyaceae, within the class Actinobacteria. This group is frequently found to be abundant within lakes across the world ( Glöckner et al, 2000 ; Warnecke, Amann & Pernthaler, 2004 ; Jiao et al, 2018 ; Kraemer et al, 2020 ) and has previously been shown to be an important component in New Zealand lakes (which included the lakes assessed here; Pearman et al, 2022 ). The small size of the Actinobacteria, may protect them from protistan grazing ( Allgaier & Grossart, 2006 ) which, combined with their ability to degrade a variety of complex organic materials, makes them competitive in lake environments ( Ghai et al, 2014 ).…”

“…The small size of the Actinobacteria, may protect them from protistan grazing ( Allgaier & Grossart, 2006 ) which, combined with their ability to degrade a variety of complex organic materials, makes them competitive in lake environments ( Ghai et al, 2014 ). The family Comamonadaceae, class Gammaproteobacteria, was another taxa which contributed substantially to the Pbact and has also previously been shown to be abundant in freshwater environments ( Willems, 2014 ; Pearman et al, 2022 ).…”

Relic DNA obscures DNA‐based profiling of multiple microbial taxonomic groups in a river‐reservoir ecosystem

“…On the other hand, stochastic processes or some uninvestigated important environmental variables might contribute to the patterns of the PMA-treated protistan and fungal communities (Wang et al, 2020). Additionally, deterministic processes may be more important for bacteria than eukaryotes in some freshwater systems (Pearman et al, 2022;Wan et al, 2023).…”