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Aquatic systems have traditionally played a key role in the development of human life, providing multiple ecosystem services to society and being a reservoir for a wide biodiversity of organisms. Among them, bacteria belonging to Legionella stand out, mainly because they are of great interest both in the field of microbial ecology and public health, since some of them turn out to be pathogenic for humans. The aim of this work was to study the monthly temporal dynamics of Legionella spp. and its relationship with the environmental variables measured in two Pampean shallow lakes (Gómez and Carpincho, Buenos Aires Province, Argentina). The analysis was carried out using a quantitative approach by real-time polymerase chain reaction (qPCR) and a non-quantitative approach using bacterial diversity data obtained by next-generation sequencing (NGS), using the Illumina MiSeq platform. Our results showed that the overall Legionella abundance was very high in the studied Pampean shallow lakes. Notably, fluctuations in dissolved organic carbon and temperature influenced the dynamics shifts in Legionella abundances. Correlation analyses between Legionella reads from NGS and copy numbers obtained through qPCR revealed positive relationships, unveiling distinctions attributable to the diverse sequence processing algorithms employed in the analysis of NGS data. [ABSTRACT FROM AUTHOR]

Text-analysis tools focused on limnology research allowed us to find three approaches in the analysis of ecosystems services (ES) provided by bacteria, archaea and viruses: (i) a prevalence of taxonomic analyses focused on the relevance of microbial biodiversity in sustaining ES, (ii) studies focused on diversity and functional aspects of bacteria, archaea and viruses and their ES provided and (iii) research focused on disservices. Supporting, regulating and provisioning services were the most discussed. Significant gaps include knowledge about the ecological traits of prokaryotic taxa and viral particles, quantitative information on microbial community-level functions integrated through different ecosystems, and a deeper integration of positive and negative microbial community functional attributes and their feedbacks to ecosystem services provision. Future research should include: (i) development of new bioinformatic tools coupled to theoretical and methodological frameworks leading to a more powerful analysis of metagenomic data, (ii) inclusion of earth observation data for comprehensive modeling of large-scale assessment of ES and its valuation, (iii) advance investigation on the ecological processes that viruses support in the environment and its significance for the ecological performance of microbial communities' services provision. [ABSTRACT FROM AUTHOR]

The biogeography of bacterial communities is a key topic in Microbial Ecology. Regarding continental water, most studies are carried out in the northern hemisphere, leaving a gap on microorganism's diversity patterns on a global scale. South America harbours approximately one third of the world's total freshwater resources, and is one of these understudied regions. To fill this gap, we compiled 16S rRNA amplicon sequencing data of microbial communities across South America continental water ecosystems, presenting the first database µSudAqua[db]. The database contains over 866 georeferenced samples from 9 different ecoregions with contextual environmental information. For its integration and validation we constructed a curated database (µSudAqua[db.sp]) using samples sequenced by Illumina MiSeq platform with commonly used prokaryote universal primers. This comprised ~60% of the total georeferenced samples of the µSudAqua[db]. This compilation was carried out in the scope of the µSudAqua collaborative network and represents one of the most complete databases of continental water microbial communities from South America. Measurement(s) taxonomic diversity assessment by targeted gene survey Technology Type(s) next generation DNA sequencing Sample Characteristic - Organism Bacteria • Archaea Sample Characteristic - Environment aquatic environment Sample Characteristic - Location South America [ABSTRACT FROM AUTHOR]

The Salado River basin, Buenos Aires, Argentina, contains numerous permanent shallow lakes under anthropic pressure due to different land uses/land covers (LULC) in their catchments. Here, we explored the relation of LULC in the surrounding areas and the physical and chemical variables of six shallow lakes of the aforementioned basin with phytoplankton structure and morpho-functional groups (MFGs) along one year and evaluated whether LULC or physical and chemical variables were more relevant in shaping phytoplankton structure. We hypothesized that: (1) shallow lakes with higher proportion of land committed to agriculture exhibit more eutrophic characteristics; (2) the phytoplankton structure and MFGs differ in shallow lakes with different LULC in their surrounding areas; and (3) LULC effects decrease with increase in buffer width. Landsat satellite images were used to extract LULC composition in three buffer zones surrounding each lake: 1, 2.5 and 5 km. In all the lakes studied, LULC had greater influence on phytoplankton MFGs than physical and chemical variables. This influence was highest for the 2.5 km buffer. The phytoplankton structure and some physical and chemical characteristics were also different between the shallow lakes studied. Cyanobacteria were widely detected, probably related to the high proportion of land dedicated to agriculture in the region. Chlorococcales, typical of these eutrophic systems, were also well represented. Our study evidenced the influence of LULC on the shallow lakes studied, particularly on the phytoplankton structure. The response of the planktonic microalgal communities to human activities in catchments evidences their value as sentinels of aquatic ecosystems. [ABSTRACT FROM AUTHOR]