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.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.Peer reviewe

Benthic algae communities in the rivers of the different water quality of lithuania

Investigation of benthic algae communities were carried out in the rivers of different water quality during the period 2004–2006. In total, 61 taxa were identified during this research. They belong to 5 divisions (Cyanobacteria, Rhodophyta, Xantophyta, Bacillariophyta, Chlorophyta), 6 classes (Cyanophyceae, Florideophyceae, Xantophyceae, Bacillariophyceae, Chlorophyceae, Conjugatophyceae) and 17 orders (Chroococcales, Oscillatoriales, Nostocales, Acrochaetiales, Batrachospermales, Hildenbrandiales, Tribonematales, Vaucheriales, Centrales, Pennales, Microsporales, Oedogoniales, Chaetophorales, Ulotrichales, Cladophorales, Tetrasporales, Zygnematales). In the rivers of different water quality the biggest variety of species belongs to cyanobacteria (Cyanobacteria) and green-algae (Chlorophyta). There were detected 25 and 19 species respectively, which accordingly constitutes 41 % and 31.1 % of the whole number of species. The variety of other species were less rich: diatom (Bacillariophyta) - 8 (13.1 %), red-algae (Rhodophyta) - 7 (11.5 %) and yellow-algae (Xantophyta) - 2 (3.3 %). During the study was mentioned that benthic algae distribution are different in the rivers of different water quality (II, III, IV and unknown water quality classes). The cross-rate of taxonomy in those rivers are similar. During the study in the rivers of different water quality the most spread are Chamaesiphon incrustans, Heteroleibleinia kossinskajae, Audouinella chalybea, Vaucheria sessilis, Cocconeis placentula, Achnanthidium minutissimum, Gomphonema truncatum, Aulacoseira islandica, Melosira varians and Cladophora glomerata species. Species which could be spread in all studied rivers haven’t been found. Very rare species are some cyanobacteria (Phormidium ambiguum, Oscillatoria tenuis, Tolypothrix tenuis, Rivularia borealis, Cylindrospermum minutissimum, Nostoc sp.) and red-algae (Audouinella hermanii, Batrachospermum anatinum, Batrachospermum sp.) species. Nine new algae species were found that were not yet detected for Lithuania. One red-algae (Audouinella hermanii) and eight cyanobacteria (Chamaesiphon amethystinus, Hydrococcus rivularis, Heteroleibleinia kossinskajae, Phormidium cliarensis, Phormidium retzii, Phormidium hamelii, Rivularia borealis and Cylindrospermum minutissimum). In the rivers of II water quality classes are spread algae communities: (Akmena (AKM-1)) Cladophora glomerata–Fontinalis antipyretica; (Babrungas (BAB-4)) Amblystegium riparium–Cladophora glomerata; (Babrungas (BAB-5)) Fontinalis antipyretica–Cladophora glomerata. In the rivers of III water quality classes are spread algae communities: (Bražuolė (BRA-4)) Vaucheria sessilis–Phormidium hamelii–Cladophora glomerata; (Bražuolė (BRA-5)) Fontinalis antipyretica–Cladophora glomerata; (Siesartis (SIE-3)) Fontinalis antipyretica–Cladophora glomerata; (Siesartis (SIE-6)) Cladophora glomerata–Potamogeton spp.–Fontinalis antipyretica; (Kulpė (KUL-3)) Cladophora glomerata; (Šeimena (ŠEI-3)) Aulacoseira islandica–Melosira varians–Cladophora glomerata–Stigeoclonium tenue; (Tatula (TAT-2)) Spirogyra sp. (I, II, III, IVa)–Oedogonium sp. (I, II)–Vaucheria sessilis. In the rivers of IV water quality classes are spread algae communities: (Lomena (LOM-4)) Cladophora glomerata–Vaucheria sessilis; (Lomena (LOM-6)) Cladophora glomerata–Potamogeton spp.; (Šalčia (ŠALČ-1)) Aulacoseira islandica–Melosira varians. The variety of the benthic algae species as well as the structure of communities could be determined by several interdependent hydrophysical and hydrochemical factors of environment. These are the variation of heterogenical substratum, velocity of stream flow, the depth of the river, intensity of light and the mane biogenes concentration. Communities more variable in species of algae are formed in those belts of rivers where all previously mentioned factors vary

Benthic algae communities in the rivers of different water quality in Lithuania

Investigation into benthic algae communities was carried out in the Lithuanian rivers of different water quality during the period 2004–2006. The structure of benthic algae communities in the rivers of different water quality slightly differs. The community of Cladophora glomerata–Vaucheria sessilis– Fontinalis antipyretica mainly dominated in the rivers. Algae communities reiterate in unpolluted rivers (II class, according to biogenes) such as Akmena, Babrungas, Bražuolė and Siesartis where Cladophora glomerata–Fontinalis antipyretica, Amblystegium riparium–Cladophora glomerata, and Fontinalis antipyretica–Cladophora glomerata communities predominate. In slightly and moderately polluted rivers, algae communities are unreiteratable. Differences in river water quality could be better determined by frequently appearing algae species in algae communities: in unpolluted rivers – Hildenbrandia rivularis, Audouinella chalybea and A. Hermanii, in slightly polluted – Vaucheria sessilis and Fontinalis antipyretica, and in moderately polluted – Stigeoclonium nanum, S. tenue, Aulacoseira islandica and Melosira varians. The variety of the structure of benthic algae communities could be determined by abiotic environmental factors such as the heterogenity of substratum, stream velocity and depth, the intensity of light and biogenes concentration. Article in Lithuanian. Bentoso dumblių bendrijos skirtingos vandens  kokybės Lietuvos upėse Anotacija. Straipsnyje pateikti 2004–2006 m. duomenys apie bentoso dumblių bendrijas skirtingos vandens kokybės Lietuvos upėse. Skirtingos vandens kokybės upėse daugiausia dominuoja Cladophora glomerata–Vaucheria sessilis–Fontinalis antipyretica dumblių samanų bendrija. Skirtingos vandens kokybės upių būklę geriau rodo bendrijose vietomis gausiai besivystančios dumblių rūšys. Švarių vandens telkinių – Hildenbrandia rivularis, Audouinella chalybea ir A. hermanii; mažai užterštų – Vaucheria sessilis ir Fontinalis antipyretica; vidutiniškai užterštų Stigeoclonium nanum, S. tenue, Aulacoseira islandica ir Melosira varians. Skirtingos vandens kokybės ir atskirų upių išilginiame pjūvyje bentoso dumblių bendrijų struktūra kito. Tai galėjo lemti substrato heterogeniškumas, vandens tekėjimo greičio, upės gylio, šviesos intensyvumo bei pagrindinių biogenų koncentracijos pokyčiai. Reikšminiai žodžiai: fitobentosas, vandens kokybė, upės, Lietuva

Factors promoting persistence of the bloom-forming Gonyostomum semen in temperate lakes

The nuisance large flagellate Gonyostomum semen (Raphidophyceae) is typical for brown-water lakes in temperate and boreal regions. This study is focused on two annual cycles of G. semen in shallow temperate lakes (one of which stratifies) with a particular emphasis on the species’ ecology and its potential impact on the alternation of phytoplankton assemblages. Temperature and phosphorus were the main forces driving seasonal growth of the raphidophyte. G. semen occurred at a broad temperature range and prevailed for the extended period from spring to late autumn at maximum biovolume and forming up to 98.7% of total phytoplankton in June–July and/or September. The species exclusively dominated under phosphate-replete conditions and caused heavy blooms in the stratified lake. The species outcompeted other flagellates in the lakes; considerable fluctuations in phytoplankton species composition occurred during the periods at low G. semen biovolume

Dumblių ir melsvabakterių kolekcija mokslui, mokymui ir biotechnologiniams tyrimams (Gamtos tyrimų centras, Lietuva)

The collection of pure cultures of algae and cyanobacteria deposited at the Nature Research Centre is a unique and diverse culture collection in Lithuania. It was initiated on the basis of a few national projects in 2010 as an outcome of ecological and molecular studies on invasive and harmful bloom-forming algae and cyanobacteria. To date, the collection holds more than 500 strains, which belong to ten classes, over 70 genera and 140 species. Strains were isolated from Lithuanian freshwaters and the Curonian Lagoon. The collection serves for various research topics including species interactions, molecular analysis, biotechnology (remediation of wastewaters, cell wall disruption, high- and low-value bioproducts), as well as for teaching purposes

Insights into cyanophage-mediated dynamics of nodularin and other non-ribosomal peptides in Nodularia spumigena

The effect of cyanophage infection and lysis on the dynamics of the hepatotoxin nodularin (NOD) and other non-ribosomal peptides (NRPs) produced by cyanobacteria is poorly understood. In this study, changes in concentration of NOD and other NRPs during cyanophage infection of the filamentous cyanobacteria Nodularia spumigena were assessed using incubation experiments. Viral infection and lysis were associated with a significant reduction (93% at the 96 h post infection) of N. spumigena cell density. While no correlation between N. spumigena abundance and total concentration of NOD (ng mL−1) within the infected cells was observed, cellular NOD quota (ng cell−1) gradually increased in the remaining cyanophage resistant N. spumigena subpopulation. Lysis of N. spumigena cells resulted in a substantial increase (>57 times) of dissolved NOD concentration in the culture medium. The relative concentration of other cyclic (anabaenopeptins) and linear (aeruginosins, spumigins) NRPs produced by N. spumigena also increased in response to cyanophage addition. This study highlights the importance of cyanophage infection on the population toxicity of filamentous cyanobacteria and demonstrates a significant contribution of virus-mediated cell lysis on the conversion of NOD from the particulate to dissolved phase

Interplay of nutrients, temperature, and competition of native and alien cyanobacteria species growth and cyanotoxin production in temperate lakes

Global warming and eutrophication contribute to formation of HABs and distribution of alien cyanobacteria northward. The current study assessed how alien to Europe Sphaerospermopsis aphanizomenoides and Chrysosporum bergii will co-occur with dominant native Planktothrix agardhii and Aphanizomenon gracile species under changing conditions in temperate freshwaters. The experiments were carried out to examine the effect of nutrients and temperature on the growth rate of cyanobacteria, production of cyanotoxins, and interspecies competition. The highest growth rate was determined for A. gracile (0.43 day-1) and S. aphanizomenoides (0.40 day-1) strains at all the tested nutrient concentrations (IP and IN were significant factors). S. aphanizomenoides adapted to the wide range of nutrient concentrations and temperature due to high species ecological plasticity; however, A. gracile was able to suppress its dominance under changing conditions. Regularity between tested variables and STX concentration in A. gracile was not found, but IP concentration negatively correlated with the amount of dmMC-RR and other non-ribosomal peptides (NRPs) in P. agardhii strains. The relative concentration of NRPs in nontoxic P. agardhii strain was up to 3-fold higher than in MC-producing strain. Our study indicated that nutrients, temperature, and species had significant effects on interspecies competition. A. gracile had a negative effect on biomass of both alien species and P. agardhii

Effect of Increased Temperature on Native and Alien Nuisance Cyanobacteria from Temperate Lakes: An Experimental Approach

In response to global warming, an increase in cyanobacterial blooms is expected. In this work, the response of two native species of Planktothrix agardhii and Aphanizomenon gracile, as well as the response of two species alien to Europe—Chrysosporum bergii and Sphaerospermopsis aphanizomenoides—to gradual temperature increase was tested. The northernmost point of alien species distribution in the European continent was recorded. The tested strains of native species were favoured at 20⁻28 °C. Alien species acted differently along temperature gradient and their growth rate was higher than native species. Temperature range of optimal growth rate for S. aphanizomenoides was similar to native species, while C. bergii was favoured at 26⁻30 °C but sensitive at 18⁻20 °C. Under all tested temperatures, non-toxic strains of the native cyanobacteria species prevailed over the toxic ones. In P. agardhii, the decrease in concentration of microcystins and other oligopeptides with the increasing temperature was related to higher growth rate. However, changes in saxitoxin concentration in A. gracile under different temperatures were not detected. Accommodating climate change perspectives, the current work showed a high necessity of further studies of temperature effect on distribution and toxicity of both native and alien cyanobacterial species