Proficiency testing and cross-laboratory method comparison to support standardisation of diatom DNA metabarcoding for freshwater biomonitoring.

DNA metabarcoding of benthic diatoms has been successfully applied for biomonitoring at the national scale and can now be considered technically ready for routine application. However, protocols and methods still vary between and within countries, limiting their transferability and the comparability of results. In order to overcome this, routine use of DNA metabarcoding for diatom biomonitoring requires knowledge of the sources of variability introduced by the different steps of the procedure.

Relative importance of climate and spatial processes in shaping species composition, functional structure and beta diversity of phytoplankton in a large river.

Although metacommunity dynamics of lentic phytoplankton are relatively well-documented, studies on the role of environmental and spatial processes in shaping phytoplankton communities of large rivers are still scarce. Here, we examined six phytoplankton data sets, which were collected in 1978-2017 from large river-scale segments (mean spatial extent 1117 km) in the Danube River. Our aim was to elucidate role of climatic, spatial and temporal predictors in variation of phytoplankton beta diversity using variance partitioning for compositions of species and functional groups sensu Reynolds.

Correction: Climate and land-use as the main drivers of recent environmental change in a mid-altitude mountain lake, Romanian Carpathians.

[This corrects the article DOI: 10.1371/journal.pone.

Exogenic production of bioactive filamentous biopolymer by monogonant rotifers.

The chemical ecology of rotifers has been little studied. A yet unknown property is presented within some monogonant rotifers, namely the ability to produce an exogenic filamentous biopolymer, named 'Rotimer'. This rotifer-specific viscoelastic fiber was observed in six different freshwater monogonants (Euchlanis dilatata, Lecane bulla, Lepadella patella, Itura aurita, Colurella adriatica and Trichocerca iernis) in exception of four species.

In situ modelling of biofilm formation in a hydrothermal spring cave.

Attachment of microorganisms to natural or artificial surfaces and the development of biofilms are complex processes which can be influenced by several factors. Nevertheless, our knowledge on biofilm formation in karstic environment is quite incomplete. The present study aimed to examine biofilm development for a year under controlled conditions in quasi-stagnant water of a hydrothermal spring cave located in the Buda Thermal Karst System (Hungary).

Cell Size Decrease and Altered Size Structure of Phytoplankton Constrain Ecosystem Functioning in the Middle Danube River Over Multiple Decades.

Reduced body size is among the universal ecological responses to global warming. Our knowledge on how altered body size affects ecosystem functioning in ectothermic aquatic organisms is still limited. We analysed trends in the cell size structure of phytoplankton in the middle Danube River over a 34-year period at multiple levels: (1) average cell size of assemblages (ACS), (2) within the centric diatom community and (3) in the dominant centric diatom taxon: .

Climate and land-use as the main drivers of recent environmental change in a mid-altitude mountain lake, Romanian Carpathians.

Recent decades have been marked by unprecendented environmental changes which threaten the integrity of freshwater systems and their ecological value. Although most of these changes can be attributed to human activities, disentagling natural and anthropogenic drivers remains a challenge. In this study, surface sediments from Lake Ighiel, a mid-altitude site in the Carpathian Mts (Romania) were investigated following high-resolution sedimentological, geochemical, environmental magnetic and diatom analyses supported by historical cartographic and documentary evidence.

Lindavia intermedia (Bacillariophyceae) and Nuisance lake Snow in New Zealand: Chitin Content and Quantitative PCR Methods to Estimate Cell Concentrations and Expression of Chitin Synthase.

Lake snow, caused by the freshwater centric diatom Lindavia intermedia, has become problematic in several large, oligotrophic New Zealand lakes over the past decade. Macroaggregates produced by L. intermedia foul fishing lines, intake screens, and water filters, and have a negative impact on recreational values.

Trait-based community assembly of epiphytic diatoms in saline astatic ponds: a test of the stress-dominance hypothesis.

The stress dominance hypothesis (SDH) postulates that strong environmental gradients drive trait convergence in communities over limiting similarity. Previous studies, conducted mostly with terrestrial plant communities, found controversial evidence for this prediction. We provide here the first test for SDH for epiphytic diatoms.

Groups of small lakes maintain larger microalgal diversity than large ones.

The question of whether one large, continuous area or many smaller habitats maintain more species is one of the most relevant questions in conservation ecology, and it is referred to as the SLOSS (Single Large Or Several Small) dilemma in the literature. This question has not yet been raised in the case of microscopic organisms, therefore we investigated whether or not the SLOSS dilemma could apply to phytoplankton and benthic diatom metacommunities. Benthic diatom and phytoplankton diversity in pools and ponds of different sizes (ranging between 10-10 m) was studied.

Unexpected consequences of bombing. Community level response of epiphytic diatoms to environmental stress in a saline bomb crater pond area.

The spatial response of epiphytic diatom communities to environmental stress was studied in a moderately saline wetland area located in the plain of Danube-Tisza Interfluve, Hungary. The area is characterised by World War II bomb crater ponds and can be regarded as an excellent ecological model system where the dispersion of species is slightly limited by distance. To study the effect of environmental variables on the communities, canonical correspondence analysis was applied.

Exceptional in vivo catabolism of neurodegeneration-related aggregates.

Neurodegenerative diseases are linked to a systemic enzyme resistance of toxic aggregated molecules and their pathological consequences. This paper presents a unique phenomenon that Philodina acuticornis, a bdelloid rotifer, is able to catabolize different types of neurotoxic peptide and protein aggregates (such as beta-amyloids /Aβ/, alpha-synuclein, and prion) without suffering any damage. P.

Wartime scars or reservoirs of biodiversity? The value of bomb crater ponds in aquatic conservation.

Considering the ongoing loss of aquatic habitats, anthropogenic ponds are gaining importance as substitute habitats. It is therefore important to assess their functioning in comparison to their natural precursors. Here we assess the biodiversity value of sodic bomb crater ponds by comparing their gamma diversity to that of natural reference habitats, astatic soda pans, and assess their importance on the landscape level by studying alpha and beta diversity.

Biogeography and phylogenetic position of a warm-stenotherm centric diatom, Skeletonema potamos (C.I. Weber) hasle and its long-term dynamics in the River Danube.

Skeletonema potamos is a poorly known freshwater species in the ancestrally and predominantly marine genus Skeletonema. With phylogenetic analysis of two nuclear {partial SSU (18S) and partial LSU (28S) rDNA)} and two chloroplast (rbcL and psbC) genes, we verified its placement within the genus Skeletonema and identified the mostly brackish species, Skeletonema subsalsum, as its closest known relative. Comparisons of SSU and LSU rRNA genes from S.

Structure and seasonal dynamics of the protozoan community (heterotrophic flagellates, ciliates, amoeboid protozoa) in the plankton of a large river (River Danube, Hungary).

Seasonal dynamics of all major protozoan groups were investigated in the plankton of the River Danube, upstream of Budapest (Hungary), by bi-weekly sampling over a 1-year long period. Sixty-one heterotrophic flagellate, 14 naked amoeba, 50 testate amoeba, 4 heliozoan and 83 ciliate morphospecies were identified. The estimated abundance ranges of major groups throughout the year were as follows: heterotrophic flagellates, 0.

Chemical and biological characterisation of biofilms formed on different substrata in Tisza river (Hungary).

Natural biofilms were simultaneously grown on granite, polished granite, andesite, polycarbonate and Plexi-glass substrata for six weeks in the Tisza River. Biofilm production and abundance of algae were influenced by the substratum. Magnitude of the substratum effect was andesite View Article and Find Full Text PDF

Ribosomal DNA sequence variation among sympatric strains of the Cyclotella meneghiniana complex (Bacillariophyceae) reveals cryptic diversity.

Cyclotella meneghiniana Kützing is one of the most commonly found and intensively studied freshwater diatom species. However, it is considered taxonomically problematic because of its unusually wide ecological range and large frustule ultrastructural variation. As part of a study of morphological and genetic variation in this morphospecies, we surveyed nucleotide variation in the hypervariable D1/D2 regions of the 28S rDNA, in the ribosomal internal transcribed spacer region (containing ITS1, the 5.