Biology subjects

Vass, M.

Publications and source records attributed to Vass, M..

5 recordsLinked to original sources

bioRxiv2024

Community stability increases the predictability of microeukaryote community coalescence outcomes

Mixing of entire microbial communities represents a frequent, yet understudied phenomenon. Here, we mimicked estuarine condition in a microcosm experiment by mixing a freshwater river community with a brackish sea community and assessed the effects of both environmental and community coalescences induced by varying mixing processes on microeukaryotic communities. Signs of shifted community composition of coalesced communities towards the sea parent community suggest asymmetrical community coalescence outcome, which, in addition, was generally less impacted by environmental coalescence. Diatoms were negatively impacted by coalescence, while fungi, ciliates, and cercozoans were promoted to varying extents, depending on the mixing ratios of the source (i.e., river or sea) communities. Community stability, inferred from community cohesion, suggests that the more stable parent community (i.e., community with greater negative cohesion attributed to competitive interactions) dominates the final, coalesced community, but the fate of its community members is influenced by mixing ratios and frequencies (i.e., one-time versus repeated coalescence). Generally, community coalescence increased alpha diversity and promoted competition from the introduction (or emergence) of additional (or rare) species. These competitive interactions in turn had community stabilizing effect as evidenced by the increased proportion of negative cohesion. Our study suggests that the predictability of coalescence outcomes was greater when the more stable parent community (i.e., sea microbes) dominated the final community and this predictability was further enhanced when communities collided repeatedly. Open research statementSequencing data is deposited to NCBI SRA database under the accession number PRJNA922225. Data (OTU table, consensus taxonomy and metadata) are available in Open Science Framework (OSF) (http://osf.io/sme36).

ecology↗

bioRxiv2022

Co-occurrences enhance our understanding of aquatic fungal metacommunity assembly and reveal potential host-parasite interactions

Our knowledge of aquatic fungal communities, their assembly, distributions and ecological roles in marine ecosystems is scarce. Hence, we aimed to investigate fungal metacommunities of coastal habitats in a subarctic zone (northern Baltic Sea, Sweden). Using a novel joint species distribution model and network approach, we quantified the importance of biotic associations contributing to the assembly of mycoplankton, further, detected potential biotic interactions between fungi-algae pairs, respectively. Our long-read metabarcoding approach identified 504 fungal taxa, of which a dominant fraction (44.8 %) was assigned as early-diverging fungi (i.e., Cryptomycota and Chytridiomycota). Alpha diversity of mycoplankton declined and community compositions changed along inlet-bay- offshore transects. The distributions of most fungi were rather influenced by spatial factors than by environmental drivers, and the influence of biotic associations was pronounced when environmental filtering was weak and spatial patterning lessened. We found great number of co-occurrences (138) among the dominant fungal groups, and the forty associations between fungal and algal OTUs suggested potential host-parasite/saprotroph links, supporting a Cryptomycota-based mycoloop pathway. We emphasize that the contribution of biotic associations to mycoplankton assembly are important to consider in future studies as it helps to improve predictions of species distributions in aquatic ecosystems.

ecology↗

bioRxiv2022

Ecosystem size-induced environmental fluctuations affect the temporal dynamics of community assembly mechanisms

Understanding processes that determine community membership and abundance is important for many fields from theoretical community ecology to conservation. However, spatial community studies are often conducted only at a single timepoint despite the known influence of temporal variability on community assembly processes. Here we used a spatiotemporal study to determine how environmental fluctuation differences induced by mesocosm volumes (larger volumes were more stable) influence assembly processes of aquatic bacterial metacommunities along a press disturbance gradient. By combining path analysis and network approaches, we found mesocosm size categories had distinct relative influences of assembly process and environmental factors that determined spatiotemporal bacterial community composition, including dispersal and species sorting by conductivity. These processes depended on, but were not affected proportionately by, mesocosm size. Low fluctuation, large mesocosms primarily developed through the interplay of species sorting that became more important over time and transient priority effects as evidenced by more time-delayed associations. High fluctuation, small mesocosms had regular disruptions to species sorting and greater importance of ecological drift and dispersal limitation indicated by lower richness and higher taxa replacement. Together, these results emphasize that environmental fluctuations influence ecosystems over time and its impacts are modified by biotic properties intrinsic to ecosystem size.

ecology↗

bioRxiv2020

Warming-enhanced priority effects at population and community levels in aquatic bacteria

The immigration history of communities can profoundly affect community composition. For instance, early-arriving species can have a lasting effect on community structure by reducing the immigration success of late-arriving ones through priority effects. Warming could possibly enhance priority effects by increasing growth rates of early-arriving bacteria. Here we implemented a full-factorial experiment with aquatic bacteria where both temperature and dispersal rate of a better-adapted community were manipulated to test their effects on the importance of priority effects, both on a community and a population level. Our results suggest that priority effects in aquatic bacteria might be primarily driven by niche preemption and strengthened by increasing temperature as warming increased the resistance of recipient communities against dispersal, and decreased the relative abundance of successfully established late-arriving bacteria. However, warming-enhanced priority effects were not always found and their strengths differed between recipient communities and dispersal rates. Nevertheless, our findings highlight the importance of context dependence of priority effects and the potential role of warming in mitigating the effects of invasion.

ecology↗

bioRxiv2019

Using null models to compare bacterial and microeukaryotic metacommunity assembly under shifting environmental conditions

Temporal variations in microbial metacommunity structure and assembly processes in response to shifts in environmental conditions are poorly understood. Hence, we conducted a temporal field study by sampling rock pools in four-day intervals during a 5-week period that included strong changes in environmental conditions due to intensive rain. We characterized bacterial and microeukaryote communities by 16S and 18S rRNA gene sequencing, respectively. Using a suite of null-model approaches to assess dynamics in community assembly, we found that strong changes in environmental conditions induced small but significant temporal changes in assembly processes and triggered different responses in bacterial and microeukaryotic metacommunities, promoting distinct selection processes. Incidence-based approaches showed that the assemblies of both communities were mainly governed by stochastic processes. In contrast, abundance-based methods indicated the dominance of historical contingency and unmeasured factors in case of bacteria and microeukaryotes, respectively, which we distinguished from dispersal-related processes using additional tests. Taken together, our study highlights that community assembly processes are not static, and the relative importance of different assembly processes can vary under different conditions and between different microbial groups.

ecology↗