Local Habitat Filtering Shapes Microbial Community Structure in Four Closely Spaced Lakes in the High Arctic

Abstract

Arctic lakes are experiencing increasingly shorter periods of ice cover due to accelerated warming at northern high latitudes. Given the control of ice cover thickness and duration over many limnological processes, these changes will have pervasive effects. However, due to their remote and extreme locations even first-order data on lake ecology is lacking for many ecosystems. The aim of this study was to characterize and compare the microbial communities of four closely spaced lakes in Stuckberry Valley (northern Ellesmere Island, Canadian Arctic Archipelago), in the coastal margin zone of the Last Ice Area, that differed in their physicochemical, morphological and catchment characteristics. We performed high-throughput amplicon sequencing of the V4 16S rRNA gene to provide inter- and intra-lake comparisons. Two deep (>25 m) and mostly oxygenated lakes showed highly similar community assemblages that were distinct from those of two shallower lakes (<10 m) with anoxic bottom waters. Proteobacteria, Verrucomicrobia, and Planctomycetes were the major phyla present in the four water bodies. One deep lake contained elevated proportions of Cyanobacteria and Thaumarchaeota that distinguished it from the others, while the shallow lakes had abundant communities of predatory bacteria, as well as microbes in their bottom waters that contribute to sulfur and methane cycles. Despite their proximity, our data suggest that local habitat filtering is the primary determinant of microbial diversity in these systems. This study provides the first detailed examination of the microbial assemblages of the Stuckberry lakes system, resulting in new insights into the microbial ecology of the High Arctic.

Seasonal shifts in microbial diversity in the lakes of Fildes Peninsula, King George Island, Maritime Antarctica

“…2016) and the Canadian High Arctic (Marois et al . 2022). In addition, some of the most representative phyla in our lakes were reported to be abundant in marine and freshwater systems, including in the Antarctic, such as members of Proteobacteria and Bacteroidota (Rochera & Camacho 2019).…”

“…Our analysis based on ASVs shows the dominance of phyla previously reported from high-latitude systems in studies employing NGS, such as in ice-free lakes from the Maritime Antarctic region (Byers Peninsula; Picazo et al 2019), ice-covered Laurentian Great Lakes (North America; Beall et al 2016) and the Canadian High Arctic (Marois et al 2022). In addition, some of the most representative phyla in our lakes were reported to be abundant in marine and freshwater systems, including in the Antarctic, such as members of Proteobacteria and Bacteroidota .…”

Response of microbial diversity and function to the degradation of Barkol Saline Lake

“…The co-occurrence network patterns revealed that the complexity of microbial community in the Barkol Saline Lake habitat was: all>sediment>degraded area. This further indicates that lake degradation will first lead to the reduction of microbial species and diversity, and second, it will further reduce the stability of community structure, which is not conducive to the protection and maintenance of the saline lake habitat ( Marois et al, 2022 ).…”

“…The predicted prevalence of sulfur metabolism genotypes, particularly sulfate respiration genotypes, was much higher in sediment samples compared to degraded areas. However, climate change has aggravated the degradation of the saline lake in recent decades, and the salt composition of sediments has also gradually changed with outside conditions ( Marois et al, 2022 ). In Barkol Lake, the main salt was sulfate compounds such as sodium sulfate or gypsum; hence, sulfur-related microorganisms were long-established functional groups.…”

Arctic bacterial diversity and connectivity in the coastal margin of the Last Ice Area

“…Actinobacteriota accounted for approximately 20% of reads throughout the water column; cells of this phylum are typically small in size and are often abundant in oligotrophic freshwaters [ 61 ]. Planctomycetota (average of 19.8% of lake reads) has also been identified as an important feature of ice-covered lakes at the far northern coast of Ellesmere Island [ 62 ], and one of the main planctomycete families in Thores Lake, the Gemmataceae , is known to include psychrotolerant taxa [ 63 ]. The high relative abundance (13%) of Anaerolineales (Phylum Chloroflexi) is also unusual for most freshwater ecosystems and implies the importance of anoxygenic aerobic phototrophy in Thores Lake.…”