18 research outputs found
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
Data Descriptor : A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins
Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment.Peer reviewe
Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer
To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L−1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long-term average, during a summer heatwave was the highest (+4°C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient-rich lakes than nutrient concentrations and surface temperature
Leaf structure and histochemical investigation in Papaver Rhoeas L. (Corn poppy, field poppy)
The anatomy of the dorsiventral, amphistomatic leaf of Papaver rhoeas was investigated. It was a simple structure possessing large epidermal cells having their vacuole impregnated with glycoproteins which varied in texture, forming a dense, hard core in the middle of the vacuole. Slender rays of cisternae radiated from the dense central core to the cell wall. Thin-walled palisade cells presented a unique, lobed shape probably creating larger surfaces for gas exchange. Mesophyll cells secreted phenolics, condensed tannins, alkaloids, terpene containing steroids and sesquiterpenes. P. rhoeas although being a therophyte, has adopted some structural features common in mediterranean phanerophytes. © 2013 Taylor & Francis Group, LLC
Hydroxyurea therapy in thalassemia
The clinical effectiveness of Hydroxyurea in thalassemia is still controversial. The present paper puts together the authors' experience in two groups of patients with thalassemia intermedia and sickle cell/β-thalassemia treated with varying dosages of hydroxyurea over several months. A third group received hydroxyurea along with recombinant human erythropoietin. Our observations are summarized in that treatment with hydroxyrea results in a significant increase of fetal hemoglobin with no change of the total hemoglobin levels. The drug causes also a considerable increase of the erythrocyte volume and hemoglobin content while the MCHC values remain unchanged. As a rule, and without objective criteria so far, patients state feeling better and having more energy. The authors postulate that this feeling may reflect the significant decrease of ineffective erythropoiesis resulting by the replacement of the poorly hemoglobinized, prematurely dying erythroid progenitor and red cell population by another population of cells with higher hemoglobin content and longer survival, the regeneration of which requires less energy and consumption. As expected, patients with sickle cell/β-thalassemia have also fewer crises and painful episodes. The above findings are in keeping with the few available reports in the literature
CYanoTech: A sustainable and innovative management system for toxic cyanobacteria blooming of surface waters with combined energy production, sustainable agriculture, and food safety
The blooming of toxic cyanobacteria in surface waters worldwide has become more persistent and prevalent, thus affecting a number of economic sectors including the tourism industry, fishery and food industry, water treatment and monitoring industry, and health sector with annual loses in the range of millions of dollars. With so many diverse sectors of modern living being affected by the same problem, it is crucial to develop and apply innovative and sustainable management systems for toxic cyanobacteria that can be easily adapted into current infrastructures. CYanoTech is a two-year project that proposes a novel, sustainable, and innovative management system for mitigating the effects of toxic cyanobacteria blooming in surface waters while combining energy production and promoting sustainable agriculture, and food safety. The CYanoTech system comprises of removal of the excess aquatic biomass (cyanobacteria cells and algae) from water with a low energy non-mechanical separation technology, the treatment of the aquatic biomass for the production of energy and marketable products (fertilizers), and the application of treated and untreated surface water in hydroponic cultures that produces safe for consumptions crops (cyanotoxins-free crops). The energy produced will compensate the total energy needs of the applied treatment processes, further reducing the system’s overall carbon footprint, making it self-sustainable. Life-Cycle-Analysis will be used to prove the system’s sustainability and market accessibility. To achieve all the project aims, the Water Treatment Laboratory- Aqua of the Cyprus University of Technology has partnered up with research groups from the Ionian University in Greece and the University of Gdansk in Poland