Biology subjects

Decaestecker, E.

Publications and source records attributed to Decaestecker, E..

5 recordsLinked to original sources

bioRxiv2025

Rapid temporal adaptation structures tolerance to toxic cyanobacteria in a natural population of the water flea Daphnia.

Cyanobacteria blooms pose a substantial threat to freshwater systems globally. While zooplankton grazers such as Daphnia can have an important role in suppressing cyanobacteria blooms, cyanobacteria can adversely impact Daphnia fitness and even kill them. Earlier work has shown an evolutionary increase in tolerance to cyanobacteria across years and strong genotype x genotype interactions determining the interaction between Daphnia and the cyanobacterium Microcystis. Here, we test the hypothesis that D. magna can adapt during one growing season to changes in dominant strains of Microcystis. Over two consecutive years, we collected D. magna clonal lineages and Microcystis strains from a single pond early and late in the growing season and we assessed whether Daphnia survival differed when exposed to Microcystis strains from either the same or a different time point within the growth season. Our findings reveal important Daphnia genotype x Microcystis genotype interactions, with Daphnia survival being higher when exposed to Microcystis from the same time point than when exposed to Microcystis of a different time point. Our results extend earlier findings to variation within one single natural system and growth season, and suggest an important impact of rapid (co)evolutionary dynamics shaping the tolerance of zooplankton grazers to cyanobacteria.

evolutionary biology↗

bioRxiv2024

How does co-occurrence of Daphnia species affect their gut microbiome?

Species co-occurrence can lead to competitive interactions that influence fitness. Competition is typically assumed to be modulated by species niche, especially food-acquisition related traits. The influence of interspecific interactions on host microbiome communities has rarely been considered, and yet may provide an alternative mechanism regarding the effect of host species co-occurrence on their fitness. Here, we investigated whether the composition of the gut microbial community differs between two Daphnia species (D. magna and D. pulex), and whether the gut microbiome of one species depends on the presence of the other. We hypothesized the stronger filter-feeder D. magna to have a larger effect on the gut microbiome of the weaker filter-feeder D. pulex than vice versa. To this purpose, three D. magna and three D. pulex genotypes were first made axenic and then grown in monocultures or in cocultures in natural environmental bacterioplankton-enriched water, before assessing the community composition of the gut microbiomes and bacterioplankton. We found that the composition of the gut microbiome of the two Daphnia species did not significantly differ overall. However, subtle differences between mono- and cocultures were found at the Daphnia genotype level. For most genotype combinations (six out of nine), the microbiome of D. pulex changed more when grown in cocultures with D. magna than in monocultures. This provides limited support for our hypothesis that the stronger competitor has a larger effect on the gut microbiome of the weaker one than vice versa, and that this effect is possibly mediated via the bacterioplankton community.

ecology↗

bioRxiv2024

Effects of microplastics on Daphnia-associated microbiomes in situ and in vitro

Microplastics (MP) pollution in aquatic environments is a growing global concern. MP, defined as plastic fragments smaller than 5mm, accumulate in freshwater reservoirs, especially those located in urban areas, impacting the resident biota. This study investigated the effects of MP on the performance and microbiome of Daphnia, a keystone organism in freshwater ecosystems, through both in situ sampling of freshwater ponds and a controlled 23-day in vitro exposure experiment. Using 16S rRNA gene sequencing and whole-genome shotgun sequencing, the microbiome community composition and functional capacity was analysed and correlated with MP pollution levels. Urban ponds showed higher MP concentrations in both water and sediment than natural ponds with significant differences in MP composition. Bacterioplankton communities were more diverse and richer than the Daphnia-associated microbiomes. Overall, the in situ study showed that the composition of the Daphnia-associated community co-varied with high MP levels but also with temperature and redox potential. Moreover, the functional analysis showed increased relative abundances of PET degradation enzymes and antibiotic resistance genes (ARGs) in microbiomes from high-MP ponds. In the in vitro experiment, the bacterioplankton inoculum source significantly influenced Daphnia survival and microbiome composition. Daphnia exposed to high MP concentrations inoculated with bacterioplankton pre-exposed to MP exhibited significantly higher survival rates, suggesting potential adaptive benefits from MP-associated microbiomes. Network analysis identified specific taxa associated with MP within the Daphnia microbiome. Our study suggests adaptive responses of freshwater host-associated microbiomes to MP pollution including biodegradation with potential benefits for the host.

ecology↗

bioRxiv2023

The effect of hypoxia on Daphnia magna performance and its associated microbial and bacterioplankton community: a scope for Genotype x Microbial community interactions upon environmental stress ?

The depletion of oxygen as a result of increased stratification and decreased oxygen solubility is one of the most significant chemical changes occurring in aquatic ecosystems as a result of global environmental change. Hence, more aquatic organisms will be exposed to hypoxic conditions over time. Deciphering the effects of hypoxia on strong ecological interactors in this ecosystems food web is critical for predicting how aquatic communities can respond to such an environmental disturbance. Here, (sub-)lethal effects of hypoxia and whether these are genotype specific in Daphnia, a keystone species of freshwater ecosystems, are studied. This is especially relevant upon studying genetic responses with respect to phenotypic switches (G x E interactions) upon environmental stress. Further, we investigated the effect of hypoxia on the Daphnia microbial community to test if the microbiome plays a role in the phenotypic switch and tolerance to hypoxia. For this, two Daphnia genotypes were exposed for two weeks to either hypoxia or normoxia and host performance was monitored together with changes in the host associated and free-living microbial community after this period. We found G x E interactions for some of the tested Daphnia performance traits. The microbial community responded to hypoxia stress with responses in the bacterioplankton and in the Daphnia associated microbial community with respect to species richness and community composition and structure. The latter response was different for the two genotypes suggesting that the microbiome plays an important role in G x E interactions with respect to hypoxia tolerance in Daphnia, but further testing (e.g. through microbiome transplants) is needed to confirm this.

ecology↗

bioRxiv2023

Host-microbiome transplants of the schistosome snail host Biomphalaria glabrata reflect species-specific associations

Snail-borne diseases affect more than a quarter of a billion people worldwide and pose a high burden in the livestock industry. A fundamental understanding of the drivers of the epidemiology of these diseases is crucial for the development of sustainable control measures. The microbiome is increasingly being recognized as an important player in the tripartite interaction between parasitic flatworms, snail intermediate hosts and the snail microbiome. In order to better understand these interactions, transplant experiments are needed, which rely on the development of a reliable and reproducible protocol to obtain microbiome-disturbed snails. Here we report on the first successful snail microbiome transplants, which indicate that Biomphalaria glabrata can accrue novel bacterial assemblies depending on the available environmental bacteria obtained from donor snails. Moreover, the phylogenetic relatedness to the donor significantly affected the survival probability of the recipients, corroborating the phylosymbiosis pattern in freshwater snails. The transplant technique described here, complemented by field-based studies, could facilitate future research endeavors to investigate the role of specific bacteria or bacterial communities in parasitic flatworm resistance of B. glabrata and might ultimately pave the way for microbiome-mediated control of snail-borne diseases.

microbiology↗