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BACKROUND Recently the utilization of microalgae for biological nutrient and organic load removal from industrial wastewater streams has been of great research interest. This present research aimed to develop a biological (algal) second cheese whey wastewater ( SCWW) treatment system able to generate renewable energy in the form of biodiesel while simultaneously removing polluting nutrients and chemical oxygen demand ( COD). RESULTS Aerobically-treated SCWW was diluted in water (dilution factor from 0.05 to 0.35) and evaluated as a substrate for Choricystis-like algal growth under photoheterotrophic conditions. Specifically, the algal culture was studied under non-aseptic conditions for its ability to remove COD, nitrogen, and phosphorous from SCWW and to produce biodiesel. At the end of treatment the pollutant load of COD, TN and PO43− was reduced by up to 92.3%, 97.3%, and 99.7%, respectively. The lipid content of the algal biomass ranged from 9.2 to 13.4%, which corresponds with an oil production of 60.8-119.5 mg L−1. The proportions of saturated and mono-unsaturated fatty acids in the lipids produced reached 79%, thus making the system suitable for biodiesel production. CONCLUSIONS A well-adapted Choricystis-like consortium could be efficiently used to treat SCWW while the biomass produced may be harnessed as a source of biodiesel. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The ecological water quality of one of the ancient world lakes, Lake Megali Prespa, is examined for the first time on the basis of its plankton communities. During the study period (October-November 2008) the lake's plankton showed signs of a moderate ecological water quality. This quality was reflected in: i) phyto- and zoo-plankton species composition which was characteristic of eutrophic conditions, ii) phytoplankton functional groups typical for eutrophic waters, iii) phytoplankton biovolume values, iv) the occurrence of blooms of several nanoplanktic species (cyanobacteria, diatoms, prymnesiophytes and cryptophytes) and v) the presence of known potentially toxin-producing cyanobacterial species. These plankton characteristics suggest a link to eutrophication and water quality degradation in the ancient Lake Megali Prespa. Water managers are advised to consider the data on plankton community and the species exchange between the lakes Megali and Mikri Prespa (high overlap of phyto- and zoo-plankton species) in their strategies for the conservation of this precious ancient lake of the world. [ABSTRACT FROM AUTHOR]

Cyanobacterial blooms have been known since ancient times; however, they are currently increasing globally. Human and ecological health risks posed by harmful cyanobacterial blooms have been recorded around the world. These risks are mainly associated with their ability to affect the ecosystem chain by different mechanisms like the production of cyanotoxins, especially microcystins. Their expansion and their harmful effects have led many researchers to seek techniques and strategies to control them. Among them, hydrogen peroxide could be a promising tool against cyanobacteria and cyanotoxins and it is well-established as an environmentally friendly oxidizing agent because of its rapid decomposition into oxygen and water. The aim of the present study was to evaluate the effect of hydrogen peroxide on phytoplankton from two hypertrophic waterbodies in Greece. The effect of hydrogen peroxide on concentration of microcystins found in the waterbodies was also studied. Treatment with 4 mg/L hydrogen peroxide was applied to water samples originated from the waterbodies and Cyanobacterial composition and biomass, phycocyanin, chlorophyll-a, and intra-cellular and total microcystin concentrations were studied. Cyanobacterial biomass and phycocyanin was reduced significantly after the application of 4 mg/L hydrogen peroxide in water treatment experiments while chlorophytes and extra-cellular microcystin concentrations were increased. Raphidiopsis (Cylindrospermopsis) raciborskii was the most affected cyanobacterial species after treatment of the water of the Karla Reservoir in comparison to Aphanizomenon favaloroi, Planktolyngbya limnetica, and Chroococcus sp. Furthermore, Microcystis aeruginosa was more resistant to the treatment of Pamvotis lake water in comparison with Microcystis wesenbergii and Microcystis panniformis. Our study showed that hydrogen peroxide differentially impacts the members of the phytoplankton community, affecting, thus, its overall efficacy. Different effects of hydrogen peroxide treatment were observed among cyanobacerial genera as well as among cyanobacterial species of the same genus. Different effects could be the result of the different resistance mechanisms of each genus or species to hydrogen peroxide. Hydrogen peroxide could be used as a treatment for the mitigation of cyanobacterial blooms in a waterbody; however, the biotic and abiotic characteristics of the waterbody should be considered. [ABSTRACT FROM AUTHOR]

The ancient lakes Mikri Prespa and Megali Prespa are located in SE Europe at the transnational triangle and are globally recognized for their ecological significance. They host hundreds of flora and fauna species, and numerous types of habitat of conservational interest. They also provide a variety of ecosystem services. Over the last few decades, the two lakes have been interconnected through a surface water channel. In an attempt to explore whether such a management practice might alter the ecological properties of the two lakes, we investigated a series of community metrics for phytoplankton by emphasizing cyanobacteria. Our results demonstrate that the cyanobacterial metacommunity structure was affected by directional hydrological connectivity and high dispersal rates, and to a lesser extent, by cyanobacterial species sorting. Cyanobacterial alpha diversity was twofold in the shallow upstream Lake Mikri Prespa (Simpson index average value: 0.70) in comparison to downstream Lake Megali Prespa (Simpson index average value: 0.37). The cyanobacterial assemblage of the latter was only a strict subset of that in Mikri Prespa. Similarly, beta diversity components clearly showed a homogenization of cyanobacteria, supporting the hypothesis that water flow enhances fluvial translocation of potentially toxic and bloom-forming cyanobacteria. Degrading of the water quality in the Lake Megali Prespa in anticipation of improving that of the Lake Mikri Prespa is an issue of great concern for the Prespa lakes' protection and conservation. [ABSTRACT FROM AUTHOR]

Lake Karla, Greece, was dried up in 1962 and its refilling started in 2009. We examined the Cyanobacteria and unicellular eukaryotes found during two fish kill incidents, in March and April 2010, in order to detect possible causative agents. Both microscopic and molecular (16S/18S rRNA gene diversity) identification were applied. Potentially toxic Cyanobacteria included representatives of the Planktothrix and Anabaena groups. Known toxic eukaryotes or parasites related to fish kill events were Prymnesium parvum and Pfiesteria cf. piscicida, the latter being reported in an inland lake for the second time. Other potentially harmful microorganisms, for fish and other aquatic life, included representatives of Fungi, Mesomycetozoa, Alveolata, and Heterokontophyta (stramenopiles). In addition, Euglenophyta, Chlorophyta, and diatoms were represented by species indicative of hypertrophic conditions. The pioneers of L. Karla's plankton during the first months of its water refilling process included species that could cause the two observed fish kill events.