Quantifiying the non-biological energy (NED) effects in cell growth and C and N uptake in Dunaliella viridis

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Cyanobacteria and Their Metabolites in Mono- and Polidominant Shallow Eutrophic Temperate Lakes

Monodominant (one species dominates) or polidominant (multiple species dominate) cyanobacterial blooms are pronounced in productive freshwater ecosystems and pose a potential threat to the biota due to the synthesis of toxins. Seasonal changes in cyanobacteria species and cyanometabolites composition were studied in two shallow temperate eutrophic lakes. Data on cyanobacteria biomass and diversity of dominant species in the lakes were combined with chemical and molecular analyses of fifteen potentially toxin-producing cyanobacteria species (248 isolates from the lakes). Anatoxin-a, saxitoxin, microcystins and other non-ribosomal peptides formed the diverse profiles in monodominant (Planktothrix agardhii) and polidominant (Aphanizomenon gracile, Limnothrix spp. and Planktolyngbya limnetica) lakes. However, the harmfulness of the blooms depended on the ability of the dominant species to synthesize cyanometabolites. It was confirmed that P. agardhii produced a greater amount and diverse range of MCs and other NRPs. In the polidominant lake, isolates of the co-dominant A. gracile, L. planctonica and P. limnetica synthesized no or only small amounts of cyanometabolites. In general, the profile of cyanometabolites was greater in cyanobacteria isolates than in environmental samples, indicating a high potential for toxic cyanobacteria bloom

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

Kamanų pelkės žaliadumblių įvairovė ir ilgalaikiai dvyniečių bendrijos pokyčiai

In Kamanos raised bog, the green algae community was represented by 160 taxa distributed into eight Chlorophyceae orders. The diversity of desmids (93 taxa) that are an essential algal component of raised bogs was most relevant. Chlorococcales comprised 30 taxa and Ulotrichales - 15 taxa. Representatives from the rest green algae groups were scarce. Higher variety of habitats in Lake Kamanos and the pools supported more diverse flora of green algae (151 taxa) compared to black hollows (61 taxa). Actinotaenium cucurbita was the single species found in all studied water bodies of Kamanos raised bog. Characium ornitocephalum, Asterococcus superbus, Cosmarium amoenum, Micrasterias truncata, Spondylosium pulchellum, Netrium digitus were found in the lake and all pools, whereas Cosmoastrum scabrum, Tetmemorus laevis - in all hollows. In the current study, the composition of desmid taxa recorded in Kamanos raised bog in two research periods was compared. The first reports on desmids were published by Vilkaitis (1937, 1940). He found 129 Desmidiales (18 genera) and 10 Zygnematales species (4 genera). Fifty five species identified by V. Vilkaitis were found repeatedly during the current investigation. In 2005, 42 species were newly recoded in Kamanos raised bog, and of these, 17 taxa were new to desmid flora of Lithuania. A numerous rare species recorded by Vilkaitis (1937) were not observed repeatedly probably due to long-term changes that had occurred in the peat bog and not enough comprehensive study that represented only part of Kamanos wetland. Some new rare desmid species (e.g. Micrasterias jenneri, Cosmarium cymatonotophorum, Desmidium cylindricum, Actinotaenium cucurbitinum, Xanthidium bifidum) have recently been found at Kamanos sites

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

Algae cell wall disruption by electrohydraulic shock

Biofuel production from algae oil is one of the most attractive process technologies. Few principles of algae cell disruption are presented on the market and introduced on the conference. Mainly, mechanical, thermal and ultra-sonication technologies are widely used in biofuel production. In this paper, authors propose a novel method for algae cell disruption – electrohydraulic shock in the water (Yutkin effect). The short-term plasma can be determined as an effective method for algae cell wall disruption. The experimental results using the proposed method as well as the biological test performed using Scenedesmus algae specie are presented

Algae cell wall disruption by electrohydraulic shock

Gamtos tyrimų centrasVytauto Didžiojo universitetasŠvietimo akademij

Investigation of stacked type ultrasonic bending system

Gamtos tyrimų centrasVytauto Didžiojo universitetasŠvietimo akademij

Algae cell wall disruption by electrohydraulic shock

Biofuel production from algae oil is one of the most attractive process technologies. Few principles of algae cell disruption are presented on the market and introduced on the conference. Mainly, mechanical, thermal and ultra-sonication technologies are widely used in biofuel production. In this paper, authors propose a novel method for algae cell disruption – electrohydraulic shock in the water (Yutkin effect). The short-term plasma can be determined as an effective method for algae cell wall disruption. The experimental results using the proposed method as well as the biological test performed using Scenedesmus algae specie are presentedGamtos tyrimų centrasVilniaus Gedimino technikos universitetasVytauto Didžiojo universitetasŠvietimo akademij