Eukaryotic Communities in Aquatic Mesocosms with and without Calcined Dolomite Investigated Using 18S rRNA Amplicon-Based Metagenomics

We report the 18S rRNA gene amplicon data from aquatic mesocosms with and without calcined dolomite. Intramacronucleata and Eumetazoa were present in roughly the same amounts in the water phase in both mesocosms. Chlorophyceae and several groups were detected as the major eukaryotes in the microbes attached to the calcined dolomite surface.

Robustness of Indoor Aquatic Mesocosm Experimentations and Data Reusability to Assess the Environmental Risks of Nanomaterials

Indoor aquatic mesocosms are increasingly used in nanosafety to assess the behavior, fate, and impacts of engineered nanomaterials (ENMs) in aquatic environments using relevant exposure scenarios. The robustness of 60 L freshwater mesocosm experimentation was tested on the basis of the reusability of the data collected in a database named MESOCOSM regarding mesocosm experiments examining the environmental risks of CeO2 ENMs. We observed high reliability of the measured variables across replicates. The sensitivity of this mesocosm methodology was evidenced by the contrasted ecosystem responses revealed by a multivariate analysis. We also observed that adding variables to the data set up to 15% did not affect the outcome of the analysis of the results. This ability to buffer this variability demonstrates that the indoor aquatic mesocosms are robust tools contributing to the environmental risk assessment of ENMs, and stresses the benefit of reusing the data stored in databases such as MESOCOSM adhering to the findable, accessible, interoperable, reusable (FAIR) data principles.

Multivariate analysis of the exposure and hazard of ceria nanomaterials in indoor aquatic mesocosms

Associating mesocosm experimentations with multivariate analyses to identify the parameters governing the behavior and impact of nanomaterials on aquatic ecosystems.

Resprouting potential of rhizome fragments from invasive macrophyte reveals superior colonization ability of the diploid congener

Non-native aquatic Ludwigia species from a polyploid complex are among the world’s most problematic invasive plants. These emergent, floating-leaved species respond to disturbance through fragmentation of shoots and/or rhizomes, spreading rapidly by hydrochorous dispersal and posing challenges for invasive plant management. While recruitment of clonal aquatic plant species from shoot fragmentation is well documented, regeneration from rhizome bud banks, although common, often is overlooked. It is further unclear how interactions among ploidy and resource availability influence regeneration success of rhizome fragments. We conducted a full factorial experiment in aquatic mesocosms to compare trait responses of Ludwigia congeners differing in ploidy (diploid, decaploid) grown from clonal rhizome fragments under contrasting soil nutrient availability (low, high). Similar to previous work with shoot fragments, the diploid congener had a higher relative growth rate and produced more biomass than the decaploid during this establishment stage of growth. High growth rates and biomass production were associated with greater rhizome N and P and reduced investment in belowground structures. Comparing these results to previous shoot fragment studies with Ludwigia, rhizome fragments appear to have much greater growth potential, suggesting that management strategies should minimize disturbance to prevent fragmentation and dispersal of belowground structures. Furthermore, rapid response to newly colonizing diploid invaders will be essential to minimizing spread, and reductions in nutrient loads to aquatic environments may be more effective toward controlling establishment of the diploid congener than the decaploid.

Sexual dimorphism in a top predator ( Notophthalmus viridescens ) drives aquatic prey community assembly

Intraspecific variation can have important consequences for the structure and function of ecological communities, and serves to link community ecology to evolutionary processes. Differences between the sexes are an overwhelmingly common form of intraspecific variation, but its community-level consequences have never been experimentally investigated. Here, we manipulate the sex ratio of a sexually dimorphic predacious newt in aquatic mesocosms, then track their impact on prey communities. Female and male newts preferentially forage in the benthic and pelagic zones, respectively, causing corresponding reductions in prey abundances in those habitats. Sex ratio differences also explained a large proportion (33%) of differences in the composition of entire pond communities. Ultimately, we demonstrate the impact of known patterns of sexual dimorphism in a predator on its prey, uncovering overlooked links between evolutionary adaptation and the structure of contemporary communities. Given the extreme prevalence of sexual dimorphism, we argue that the independent evolution of the sexes will often have important consequences for ecological communities.

Environmental exposure of a simulated pond ecosystem to a CuO nanoparticle-based wood stain throughout its life cycle

Indoor aquatic mesocosms were used to assess the behavior of a wood stain containing CuO nanoparticles in a simulated pond ecosystem for 1 month.