Phylogenomic and Pangenomic Assessment of a Mediterranean Strain of Raphidiopsis raciborskii Extends Knowledge of the Global Distribution and Characteristics of a Potentially Toxigenic Cyanobacterium.

Among potentially toxigenic cyanobacteria, Raphidiopsis raciborskii has attracted considerable attention due to its ability to produce massive blooms and its recent spread to temperate regions. In this work, we reported for the first time a taxonomic and functional assessment of a R. raciborskii strain isolated from the Mediterranean region, contributing to filling a gap in the global distribution and characteristics of this species.

Use of process-based coupled ecological-hydrodynamic models to support lake water ecosystem service protection planning at the regional scale.

Protection plans of lake waters are based on ecological and/or chemical targets, often simplified in terms of total phosphorus (TP) concentrations, customarily the depth-averaged ones at spring mixing for temperate environments. These target lake TP concentrations are then commonly employed to determine target external loading through reverse use of Vollenweider-OECD-type steady-state empirical models. Such models are also adopted in their direct form to estimate lake TP concentrations following hypothetical external load reductions.

From small water bodies to lakes: Exploring the diversity of freshwater bacteria in an Alpine Biosphere Reserve.

Small water bodies, although supporting high biodiversity, are often understudied in the Alpine region. In this work, we characterized the planktic and benthic bacterial communities, as well as the water chemistry, of a wide physiographic range of 19 freshwater bodies within an Alpine Biosphere Reserve, including ponds, pasture ponds, peat bogs, shallow lakes, and lakes. We collected both water and surface sediment samples, followed by metabarcoding analysis based on the V3-V4 regions of the 16S rRNA gene.

Taxonomic and functional metagenomic assessment of a Dolichospermum bloom in a large and deep lake south of the Alps.

Untargeted genetic approaches can be used to explore the high metabolic versatility of cyanobacteria. In this context, a comprehensive metagenomic shotgun analysis was performed on a population of Dolichospermum lemmermannii collected during a surface bloom in Lake Garda in the summer of 2020. Using a phylogenomic approach, the almost complete metagenome-assembled genome obtained from the analysis allowed to clarify the taxonomic position of the species within the genus Dolichospermum and contributed to frame the taxonomy of this genus within the ADA group (Anabaena/Dolichospermum/Aphanizomenon).

Distribution of toxigenic cyanobacteria in Alpine lakes and rivers as revealed by molecular screening.

The increasing frequency of cyanobacteria blooms in waterbodies caused by ecosystem eutrophication could endanger human health. This risk can be mitigated by effective monitoring incorporating molecular methods. To date, most molecular studies on toxigenic cyanobacteria have been limited to microcystins (MCs), disregarding other cyanotoxins, to freshwater planktic habitats while ignoring benthic habitats, and to limited geographic areas (usually one or a few specific waterbodies).

Distribution and Genetic Lineages of the Species Complex (Cnidaria, Olindiidae) in Italy.

Olindiid freshwater jellyfishes of the genus Lankester, 1880 are native to eastern Asia; however, some species within the genus have been introduced worldwide and are nowadays present in all continents except Antarctica. To date, there is no consensus regarding the taxonomy within the genus due to the morphological plasticity of the medusa stages. The species Lankester, 1880 was first recorded in Italy in 1946, and until 2017, sightings of the jellyfish were reported for 40 water bodies.

Draft genome sequence of the anatoxin-a producing cyanobacterium B0820 isolated from the epilimnion of the deep Alpine Lake Garda.

We report the draft genome sequence of strain B0820 of the cyanobacterium isolated from the epilimnion of Lake Garda and assembled from a metagenome of a non-axenic culture. The strain analyzed was shown to produce anatoxin-a, a potent neurotoxin that can cause fatal intoxication in exposed organisms.

DNA sequence and taxonomic gap analyses to quantify the coverage of aquatic cyanobacteria and eukaryotic microalgae in reference databases: Results of a survey in the Alpine region.

The taxonomic identification of organisms based on the amplification of specific genetic markers (metabarcoding) implicitly requires adequate discriminatory information and taxonomic coverage of environmental DNA sequences in taxonomic databases. These requirements were quantitatively examined by comparing the determination of cyanobacteria and microalgae obtained by metabarcoding and light microscopy. We used planktic and biofilm samples collected in 37 lakes and 22 rivers across the Alpine region.

Freshwater phytoplankton diversity: models, drivers and implications for ecosystem properties.

Our understanding on phytoplankton diversity has largely been progressing since the publication of Hutchinson on the paradox of the plankton. In this paper, we summarise some major steps in phytoplankton ecology in the context of mechanisms underlying phytoplankton diversity. Here, we provide a framework for phytoplankton community assembly and an overview of measures on taxonomic and functional diversity.

Unraveling the Diversity of Eukaryotic Microplankton in a Large and Deep Perialpine Lake Using a High Throughput Sequencing Approach.

The structure of microbial communities, microalgae, heterotrophic protozoa and fungi contributes to characterize food webs and productivity and, from an anthropogenic point of view, the qualitative characteristics of water bodies. Traditionally, in freshwater environments many investigations have been directed to the study of pelagic microalgae ("phytoplankton") and periphyton (i.e.

Effects of Habitat Partitioning on the Distribution of Bacterioplankton in Deep Lakes.

In deep lakes, many investigations highlighted the existence of exclusive groups of bacteria adapted to deep oxygenated and hypoxic and anoxic hypolimnia. Nevertheless, the extent of bacterial strain diversity has been much less scrutinized. This aspect is essential for an unbiased estimation of genetic variation, biodiversity, and population structure, which are essential for studying important research questions such as biogeographical patterns, temporal and spatial variability and the environmental factors affecting this variability.

Draft Genome Sequence of the Cadmium-Resistant Strain JJU2, Belonging to the Family Hapalosiphonaceae of the Cyanobacteria.

Here, we report the genome of strain JJU2, a cyanobacterium of the family known to be resistant to high cadmium levels, assembled from a nonaxenic, unialgal culture from Marinduque, Philippines. The draft genome is 7.1 Mb long with a GC content of 40.

Effects of climatically-modulated changes in solar radiation and wind speed on spring phytoplankton community dynamics in Lake Taihu, China.

Many studies have focused on the interactive effects of temperature increases due to global warming and nutrient enrichment on phytoplankton communities. Recently, non-temperature effects of climate change (e.g.

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins.

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.

Draft Genome Sequences of Novel , , and [corrected] Strains from a Freshwater Ecosystem.

Freshwater ecosystems represent 0.01% of the water on Earth, but they support 6% of global biodiversity that is still mostly uncharacterized. Here, we describe the genome sequences of three strains belonging to novel species in the , , and genera recovered from a water sample of Lake Garda, Italy.

Diversity and Cyclical Seasonal Transitions in the Bacterial Community in a Large and Deep Perialpine Lake.

High-throughput sequencing (HTS) was used to analyze the seasonal variations in the bacterioplankton community composition (BCC) in the euphotic layer of a large and deep lake south of the Alps (Lake Garda). The BCC was analyzed throughout two annual cycles by monthly samplings using the amplification and sequencing of the V3-V4 hypervariable region of the 16S rRNA gene by the MiSeq Illumina platform. The dominant and most diverse bacterioplankton phyla were among the more frequently reported in freshwater ecosystems, including the Proteobacteria, Cyanobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria, and Planctomycetes.

Draft Genome Sequence of the Planktic Cyanobacterium , Isolated from Alpine Lentic Freshwater.

We describe here the draft genome sequence of the cyanobacterium , assembled from a metagenome of a nonaxenic culture. The strain (FEM_GT703) was isolated from a freshwater sample taken from Lake Garda, Italy. The draft genome sequence represents the first assembled strain.