Gut microbiota can crucially influence behavior and neurodevelopment. Dogs show unique similarities to humans in their physiology and may naturally develop dementia-like cognitive decline. We assessed 29 pet dogs’ cognitive performance in a memory test and analyzed the bacterial 16S rRNA gene from fecal samples collected right after the behavioral tests. The major phyla identified in the dog microbiomes were Bacteroidetes, Firmicutes, and Fusobacteria, each represented by >20% of the total bacterial community. Fewer Fusobacteria were found in older dogs and better memory performance was associated with a lower proportion of Actinobacteria. Our preliminary findings support the existence of links between gut microbiota, age, and cognitive performance in pet dogs.

Soda lime is a by-product of the Solvay soda process for the production of sodium carbonate from limestone and sodium chloride. Due to a high salt concentration and alkaline pH, the lime is considered as a potential habitat of haloalkaliphilic and haloalkalitolerant microbial communities. This artificial and unique environment is nutrient-poor and devoid of vegetation, due in part to semi-arid, saline and alkaline conditions. Samples taken from the surface layer of the lime and from the depth of 2 m (both having pH ~11 and EC_e up to 423 dS m⁻¹) were investigated using culture-based (culturing on alkaline medium) and culture-independent microbiological approaches (microscopic analyses and pyrosequencing). A surprisingly diverse bacterial community was discovered in this highly saline, alkaline and nutrient-poor environment, with the bacterial phyla Proteobacteria (representing 52.8% of the total bacterial community) and Firmicutes (16.6%) showing dominance. Compared to the surface layer, higher bacterial abundance and diversity values were detected in the deep zone, where more stable environmental conditions may occur. The surface layer was dominated by members of the genera Phenylobacterium, Chelativorans and Skermanella, while in the interior layer the genus Fictibacillus was dominant. The culturable aerobic, haloalkaliphilic bacteria strains isolated in this study belonged mostly to the genus Bacillus and were closely related to the species Bacillus pseudofirmus, B. cereus, B. plakortidis, B. thuringensis and B. pumilus.

Aim: Waterbirds are important dispersal vectors of multicellular organisms; however, no study to date has focused on their potential role in dispersing aquatic microbial communities. We explicitly studied endozoochory of prokaryotes and unicellular microeukaryotes by waterbirds using DNA metabarcoding. By directly comparing the dispersed set of organisms to the source pool of a natural metacommunity, we aimed at a realistic estimate of the importance of waterbird zoochory for natural microbial communities.Location: Temporary saline soda pans in Austria and Hungary.Taxon: Prokaryotes and unicellular microeukaryotes.Methods: In 2017 and 2018, water samples were collected from a network of 25 temporary ponds along with fresh droppings of five waterbird species including the dominant greylag goose (Anser anser). Prokaryotic and microeukaryotic communities were identified via 16S and 18S rRNA gene amplicon sequencing. After quality filtering of sequence reads, pro‐ and microeukaryotic amplicon sequence variant (ASV) compositions were compared between the aquatic and dropping samples, across years and waterbird species.Results: 28% of the dominant aquatic prokaryotic and 19% of the microeukaryotic ASVs were transported by A. anser. ASV richness was lower, but compositional variation was higher in A. anser droppings than in aquatic communities, probably resulting from stochastic pick‐up from multiple aquatic habitats. The composition of prokaryotic ASVs in bird droppings differed among the 2 years and reflected the actual aquatic communities. The dispersed set of microbes were largely similar among the waterbird species except for the planktivore filter‐feeder northern shoveler (Spatula clypeata), which dispersed more microeukaryotes than the other waterbirds.Main conclusions: Using an amplicon sequencing approach to characterize aquatic microorganisms in waterbird droppings and in the associated environment, our study provides strong evidence for endozoochory of natural communities. These results imply that waterbirds may be crucial in maintaining ecological connectivity between aquatic habitats at the level of microbial communities.