Genome Sequences of Microviruses Identified in a Sample from a Sewage Treatment Oxidation Pond

Oxidation ponds are often used in the treatment of sewage as an aeration step prior to discharge. We identified 99 microvirus genomes from a sample from a sewage oxidation pond. This diverse group of microviruses expands our knowledge of bacteriophages associated with sewage oxidation pond ecosystems.

The ecology of ponds in the context of human activity and geography – environmental DNA and beyond

Pond ecosystems are hotspots of freshwater biodiversity, often containing many rare and protected species that are not commonly found elsewhere (Harper et al. 2018;Harper et al. 2019). However, even if they constitute c.a. 30% of freshwaters by area, still not enough effort has been put into pond monitoring and management and pond ecosystems are hence relatively poorly understood. Results of ECOPOND project will lead to add valuable knowledge upon pond diversity in geographic gradient taking for consideration human impact by comparing rural and urban areas. The sample design in ECOPOND includes six geographic regions, spanning from the south of Poland to the middle of Norway, where we will sample five replicates of urban and rural ponds in close geographic proximity, making it possible to test the impact of urbanization on biodiversity and biotic homogenization across latitude. We will sample all ponds at spring and late summer, making it possible to assess also seasonality in biodiversity. ECOPOND will utilize environmental DNA and RNA to perform biodiversity screening. The extracted eDNA and eRNA fragments will be amplified with the use of several selected markers for vertebrates, invertebrates, fungi and bacteria. Comparisons between eDNA and eRNA metabarcoding are hypothesized to allow inference between present and past diversity, as eRNA is thought to be only available from live organisms in the community. Moreover, ECOPOND aims at testing the effects of selected invasives species that can have on whole ecosystems. By sampling a range of biotic and abiotic parameters describing studied ponds, we will incorporate the available data for the ponds and employ occupancy modelling methods to assess the habitat preferences of selected invasive alien species. Then we will develop a method that can contribute towards an earlywarning system of evaluating threats to ecosystem status. One of the focus species will be the parasitic fungus Batrachochytrium dendrobatidis (Bd), an infectious fungal pathogen that has caused a number of amphibian declines and extinctions. The European amphibians seem less affected by the parasite at present. However, the fungi could be a direct driver of reduced genetic variation due to selection, or directly reduce the infected amphibian’s overall fitness by reducing the microbiotic diversity on their skin, which in many cases acts as a second immune system. ECOPOND will therefore provide data on genomic variation (using RADseq) for two amphibian species: the smooth newt (Lissotriton vulgaris) and the common toad (Bufo bufo). We will investigate populations of these species inhabiting ponds that are infected and not infected by Bd as well as collect data on their skin microbes (identified using metabarcoding). We will also contrast the genomic diversity between the replicated urban/rural setup and look for repeatable genomic changes. This setup will also be compared for the genomic variation for a potential native prey, the blue-tailed dragonfly, as will ponds with and without fish and/or amphibians (possibly also comparing between native and IAS top-predators) in order to look for predatory selective sweeps in the genome and transcriptome (experimental setup). All ponds will also be analyzed for over 20 water quality parameters and include data on a range of site characteristics that will be used as explanatory variables in all models. ECOPOND will compare large datasets across large geographic regions and will provide detailed knowledge of biodiversity patterns in vertebrates, invertebrates, fungal and microbial species, as well as genomic composition and skin biodiversity for animals inhabiting the same ponds set in an urban context. As a total, ECOPOND will obtain data on the location and status of biodiversity interests, gather data that can help in preventing the establishment of invasive alien species, and eradicating or controlling species that have already become established. And finally, ECOPOND will work closely with stakeholders and develop statistical techniques that can be used for monitoring, detection and protection of biodiversity.

Drought may amplify the impacts of salt pollution in pond ecosystems: an experimental exploration

Pond ecosystems are biodiversity-rich habitats, which support great biological diversity and provide important ecological services, but increasingly face risk of pollution and drought events. With increase in use of road-salts, ponds become vulnerable to high levels of salt pollution and may impair their biological communities and ecosystem functions. However, understanding the impacts of these two threats combined are limited. In this study, we experimentally investigated the impacts of road-salt pollution and the expected future increase in drought events on ponds' physical conditions, communities and ecosystem functions. In a two-way factorial design, 20 experimental mesocosms were used to test the individual and combined effects of climate change-driven drought events and salt pollution on natural pond ecosystems. Treatments were presence or absence of water salinization to mimic pollution by road-salts, and drying to mimic drought events. Our drought treatment doubled water salinity during the experimental period. While salt additions significantly affected ponds' physical conditions and leaf litter decomposition, both salt additions and drying showed no independent impacts on pond biota and ecosystem functions. However, our path analysis revealed that drying indirectly reduced leaf litter decomposition and eco-system productivity through changes in ponds' physical conditions, although it did not affect biomass of insects and periphyton. Overall, our findings suggest that anticipated drought events will amplify road-salt pollution, and subsequently affect ponds' biodiversity, food webs, and ecosystem functions. Implications for restoration, conservation and climate change adaptation may include actively managing snow-melting salts and long-term monitoring of changes in ponds' biophysical conditions and ecological functions.

Using Bioinformatics to Quantify the Variability and Diversity of the Microbial Community Structure in Pond Ecosystems of a Subtropical Catchment

Background: In rural China, many natural water bodies and farmlands have been converted to fish farming ponds as an economic development strategy. There is still a limited understanding of how the diversity and structure of microbial communities change in natural and managed fish pond ecosystems. Objective: We aimed to identify the changes of the diversity and structure of microbial community and driving mechanism in pond ecosystems. Methods: The datasets of 16S rRNA amplicon sequencing and the concentrations of N and P fractions were achieved in water samplers of pond ecosystems. Bioinformatics analysis was used to analyze the diversity and structure of the microbial communities. Results: Our results indicated that the diversity and structure of the microbial communities in the natural ponds were significantly different from ones in managed fish ponds. The nutrients of N and P and water environmental factors were responsible for 46.3% and 19.5% of the changes in the structure and diversity of the microbial community, respectively. Conclusion: The N and P fractions and water environmental factors influenced the microbial community structure and diversity in pond ecosystems. Fish farming indirectly affected the microbial community by altering the contents of N and P fractions in water bodies of ponds when a natural pond was converted to a managed fish pond. Conclusion: The N and P fractions and water environmental factors influenced the microbial community structure and diversity in pond ecosystems. Fish farming indirectly affected the microbial community by altering the contents of N and P fractions in water bodies of ponds when a natural pond was converted to a managed fish pond.