Water Algae Research Articles

Removal of Microcystis aeruginosa by UV-activated persulfate: Performance and characteristics

Cyanobacteria blooms in source waters have become a worldwide issue for drinking water production. UV-activated persulfate (UV/PS) technology was firstly applied to remove cultivated Microcystis aeruginosa (M. aeruginosa) in bench scale. The presence of persulfate significantly enhanced both cytoclasis and algal organic matter mineralization compared with UV-C inactivation alone. Around 98.2% of algal cells were removed after UV/PS process treatment for 2h at a dosage of PS being 1500mg/L (approximately 6mM). Both sulfate and hydroxyl radicals were proven to contribute to the removal of algae and the loss of cell integrity. The cultivated M. aeruginosa in death growth phase were found to be more vulnerable to UV/PS treatment than those growing in log phase, thus a significant lower dosage of PS is needed to achieve the desired removal efficiency. This study suggested a novel application of UV/PS process in the removal of algae in source waters due to the high degradation efficiency of both algal cells and their derived organic matter.

Implications of climate variability and change for African lake ecosystems, fisheries productivity, and livelihoods

Abstract Inland fisheries are important for nutrition, employment, and income, but climate variability and change are adding to other stressors, such as overexploitation, pollution, habitat degradation, and invasive species, to threaten their productivity as well as livelihoods of fisheries-dependent communities. Understanding the whole socio-ecological system to enable communities to adapt and build resilience is therefore vital. Here, we present results from a review of the responses of African lakes, fisheries productivity, and livelihoods to climate variability and change, and provide suggestions on required policy interventions to promote adaptation and build resilience. Changes in climate variables, especially temperature, wind speed, and rainfall have contributed to changes in lake water levels, loading, and recycling of nutrients. In some lakes, such disruptions in physical and chemical conditions have triggered changes in water quality, algae and invertebrate productivity, life history of fish, and contributed to shifts in fish community composition, proliferation of invasive aquatic weeds, and changes in parasite–vector–host interactions. Fish yield has either increased or decreased depending on climatic events, with the latter negatively affecting livelihoods, and forcing affected communities to adapt. Because adaptation strategies are location specific, and influenced by local conditions, many adaptation strategies have been unguided and have negatively affected fisheries. The responses of fisheries to climate change vary among lakes of different morphometric characteristics. There is need for consistent data to examine the direction and consequences of climate variability and change on fisheries and livelihoods of specific aquatic systems, and promote location specific adaptation and mitigation measures.

Dynamics of physiologically active cells of pico- and nanophytoplankton in the coastal waters of Black Sea

The dynamics of the abundance and viability index (VI) of pico- and nanophytoplankton in the coastal waters of Black Sea near Sevastopol were investigated by regular monthly monitoring using flow cytometry and fluorescein diacetate vital dye (FDA), as a marker of intracellular enzyme activity. Directed seasonal changes in the fraction of physiologically active cells in the study groups of algae in coastal waters was not identified. It is noted that, in the warm season and during vegetative growth of algae in the composition and pico nano-phytoplankton predominate living cells, the percentage of which varies from 70 to 100 %. Low values of the VI (30 %) picophytoplankton were obtained at individual stations in September, October and December, possibly due to the presence of this kind of cell size group Synechococcus, which are very sensitive to fluctuations of environmental factors. Refs 28. Figs 7.

Origin and paleoenvironment of Pleistocene–Holocene Travertine deposit from the Mbéré sedimentary sub-basin along the Central Cameroon shear zone: Insights from petrology and palynology and evidence for neotectonics

The Mbéré sub-basin belongs to the Mbéré-Djerem intra-continental basin of Central North Cameroon. In this sub-basin, a travertine outcrop has been discovered and investigated palynologically and petrologically in this study. The sporopollinic content of the studied travertine is mainly composed of fungal spores (Rhyzophagites sp., Monoporisporites sp …) associated with rare fresh water algae spores such as Chomotriletes minor and angiosperm pollens (compositae, graminae, …). This sporopollinic association is indicative of hot and semi-arid to arid paleoclimate and reveals a Pleistocene–Holocene depositional age. The whole rock major element geochemistry shows relative enrichment of CaO (49.48%) and CO2 (38.49%). The origin of CO2 is probably from magmatic and/or metamorphic fluids. Compared to other travertines, SiO2 and Al2O3 contents are significant with average concentrations of 5.68% and 2.58% respectively. The mineralogical composition revealed by a microscopic study of bulk rocks is dominated by calcite (90–92%) associated to quartz (2–4%) and feldspar (2–3%), meanwhile the heavy mineral concentrate is formed by various mineral types such as zircon (most abundant), garnet, tourmaline, epidote, biotite, peridot and aegirine augite suggesting that the underground water has crossed both volcanic, plutonic and metamorphic rocks. With the mineral composition made of both chemical and detrital derived elements, the Mbéré travertine corresponds to chemico-lithoclastic/detrital limestone. In the Mbéré trough, numerous thermo-mineral springs are located along major fractures and faults. This result suggests that the Mbéré travertine deposit is related to the rising of deep water with the help of a fracturing system, similar to those of Irdi (Morocco), Italy and Turkey where there is much volcanism.

“Anionic H-Bonds” Structure Two Simple Bilayers, One Natural

“Anionic H-Bonds” Structure Two Simple Bilayers, One Natural Living membranes consist of bilayers of primarily anionic polar lipids. We describe two simple, single-chain lipid bilayers: pure oleate C18Δ9 carboxylate, and a chlorosulfolipid (CSL), a C24, hexachloro-1,14-disulfate, from the fresh water (pH 4.3) alga, Ochromonas danica. Oleate bilayers are formed either from Na-oleate or from micelles of oleic acid. Both monolayer headgroups, carboxylate and sulfate, trap a H+ between their oxyanion pairs, (“anionic H-bond”). In an aprotic medium they have strong H-bonds (<=20 kcal/bond), analogous to the maleate anion (JACS 2015, 137, 5730). The maleate anionic H-bond is stabilized by ring strain; here van der Waals interactions between the thin methylene chains, together with the bulk of both headgroups, compacts oxyanions forming the anionic H-bonds. O. danica's CSLs’ sulfates, at C1 and C14, form two sulfate sheets, one at C1 between headgroup pairs and the other at C14 in the low dielectric domain. There aren’t other lipids nor proteins in the O. danica surface bilayers. Thus each bilayer has four sulfate sheets, two at C1,C14. Computations show that chloro groups bond hydronium ions at near covalent bond strength in a hydrophobic domain. Inside each monolayer, the C14-sulfate sheet creates a negative field deep in the bilayer. Two chloros are on C2 adjacent to the C1-sulfate surface. They attract hydronium ions to the surface bilayer, each brings water and H+ to the C14 sulfate sheet. Water stabilizes the sulfate sheet and H+ forms anionic H-bonds between sulfates. These four strong sheets protect O. danica from osmotic bursting as do walls in prokaryotes.

How heterogeneous are adolescents’ preferences for natural and semi-natural riverscapes as recreational settings?

Recent research has indicated that the younger generations may be disconnected from nature and even show some dislike for natural conditions. This study addressed adolescents’ preferences for riverscapes with varying fluvial dynamics as recreational settings. A stated choice survey with digitally calibrated river scenarios asked Austrian pupils (N = 281) about their preferences for several physical and social characteristics of a floodplain landscape. Pupils perceived riverscapes with a high water dynamic as best for recreation, while water bodies with low water levels and algae, dry river sites, floods and littered trails were disliked. Heterogeneity among the pupils was found with one smaller segment preferring settings with high water dynamic and low human impact, while the larger one preferred settings with more human impact and low water dynamic. This segment that shows some dislike for natural conditions had less experience with rivers and scored lower on natural river-related attitudes and perceptions. Implications for recreational river planning and aesthetic assessments are derived.

Water-floating nanohybrid films of layered titanate–graphene for sanitization of algae without secondary pollution

A novel efficient and safe methodology to sanitize algae in natural water without secondary pollution is developed by fabricating floating graphene–inorganic hybrid films.

Fast, rugged and sensitive ultra high pressure liquid chromatography tandem mass spectrometry method for analysis of cyanotoxins in raw water and drinking water—First findings of anatoxins, cylindrospermopsins and microcystin variants in Swedish source waters and infiltration ponds

Freshwater blooms of cyanobacteria (blue–green algae) in source waters are generally composed of several different strains with the capability to produce a variety of toxins. The major exposure routes for humans are direct contact with recreational waters and ingestion of drinking water not efficiently treated. The ultra high pressure liquid chromatography tandem mass spectrometry based analytical method presented here allows simultaneous analysis of 22 cyanotoxins from different toxin groups, including anatoxins, cylindrospermopsins, nodularin and microcystins in raw water and drinking water. The use of reference standards enables correct identification of toxins as well as precision of the quantification and due to matrix effects, recovery correction is required. The multi-toxin group method presented here, does not compromise sensitivity, despite the large number of analytes. The limit of quantification was set to 0.1μg/L for 75% of the cyanotoxins in drinking water and 0.5μg/L for all cyanotoxins in raw water, which is compliant with the WHO guidance value for microcystin-LR. The matrix effects experienced during analysis were reasonable for most analytes, considering the large volume injected into the mass spectrometer. The time of analysis, including lysing of cell bound toxins, is less than three hours. Furthermore, the method was tested in Swedish source waters and infiltration ponds resulting in evidence of presence of anatoxin, homo-anatoxin, cylindrospermopsin and several variants of microcystins for the first time in Sweden, proving its usefulness.

Hydrothermal liquefaction of freshwater and marine algal biomass: A novel approach to produce distillate fuel fractions through blending and co-processing of biocrude with petrocrude

Biocrude was produced from Tetraselmis sp. – a marine alga and Arthrospira platensis – a fresh water alga using hydrothermal liquefaction (HTL) process. Considering the constraints in cultivating algae for replacing 100% petrocrude, this study evaluated the option of blending and co-processing algal biocrude with petrocrude. Biocrudes obtained from algal strains cultivated in fresh water and sea water were blended with petrocrude at 10% concentration and the characteristics were studied using FT-IR and CNS SIMDIST. True Boiling Point (TBP) distillation was carried out to assess yields and properties of distillates of blended biocrudes. Biocrudes obtained from both algae were light crudes and the blended crudes recorded distillate yields of 76–77wt%. The yield of light naphtha fraction of biocrude blends was 29–30%; whereas the yield of diesel fraction was about 18%. This study proposes blending and co-processing of algal biocrude with petrocrude to produce drop-in biofuels.

Preliminary observations on the preservation of organic-walled algae in shallow, freshwater lakes from south–central Missouri, USA

Algal palynomorphs can provide key ecological information about aquatic environments, yet the preservation potential for most varieties of algae is poorly understood. Cores from Pine Forest and Bray Area lakes, two man-made lakes in the Rolla area of south–central Missouri, USA, provided an opportunity to relate the algal palynomorphs in the top 9 cm of sediments to the processes that lead to preservation. By comparing algal palynomorphs in the sediments to the algal crop in the water, this study seeks to assess the effects of taphonomy on the assemblage in a palynological sample. The lakes were ecologically monitored four times in one year (late fall, spring, summer, winter) to determine the algal crop, and surficial sediment was sampled in Pine Forest Lake once in early winter. The annual average abundance of algae in the lake water was compared with sediment data, and statistical techniques (Kruskal–Wallis test, Mann–Whitney U-test and Pielou's Equitability index) were used to determine ecological stability in the sediments. While Sphaerocystis and Ceratium hirundinella did not apparently preserve well, moderate to high preservation potential was determined for Staurastrum and Botryococcus. In addition, Pediastrum simplex var. pseudoglabrum, P. integrum and P. boryanum var. pseudoglabrum were well preserved in the sediments. This preliminary study shows that a highly abundant algal species in the water may not be well preserved in the sediment. Therefore, higher resolution studies are needed to further explore the preservation potential of algae in lake sediments.

Heavy metal uptake capacity of fresh water algae (Oedogonium westti) from aqueous solution: A mesocosm research

ABSTRACTThe green macroalgae present in freshwater ecosystems have attracted a great attention of the world scientists for removal of heavy metals from wastewater. In this mesocosm study, the uptake rates of heavy metals such as cadmium (Cd), nickel (Ni), chromium (Cr), and lead (Pb) by Oedogonium westi (O. westti) were measured. The equilibrium adsorption capabilities of O. westti were different for Cd, Ni, Cr, and Pb (0.974, 0.418, 0.620, and 0.261 mgg–1, respectively) at 18°C and pH 5.0. Furthermore, the removal efficiencies for Cd, Cr, Ni and Pb were observed from 55–95%, 61–93%, 59–89%, and 61–96%, respectively. The highest removal efficiency was observed for Cd and Cr from aqueous solution at acidic pH and low initial metal concentrations. However, the removal efficiencies of Ni and Pb were higher at high pH and high concentrations of metals in aqueous solution. The results summarized that O. westti is a suitable candidate for removal of selected toxic heavy metals from the aqueous solutions.

Novel Electrokinetic Microfluidic Detector for Evaluating Effectiveness of Microalgae Disinfection in Ship Ballast Water.

Ship ballast water treatment methods face many technical challenges. The effectiveness of every treatment method usually is evaluated by using large scale equipment and a large volume of samples, which involves time-consuming, laborious, and complex operations. This paper reports the development of a novel, simple and fast platform of methodology in evaluating the efficiency and the best parameters for ballast water treatment systems, particularly in chemical disinfection. In this study, a microfluidic chip with six sample wells and a waste well was designed, where sample transportation was controlled by electrokinetic flow. The performance of this microfluidic platform was evaluated by detecting the disinfection of Dunaliella salina (D. salina) algae in ballast water treated by sodium hypochlorite (NaClO) solution. Light-induced chlorophyll fluorescence (LICF) intensity was used to determine the viability of microalgae cells in the system, which can be operated automatically with the dimension of the detector as small as 50 mm × 24 mm × 5 mm. The 40 µL volume of sample solution was used for each treatment condition test and the validity of detection can be accomplished within about five min. The results show that the viability of microalgae cells under different treatment conditions can be determined accurately and further optimal treatment conditions including concentrations of NaClO and treatment time can also be obtained. These results can provide accurate evaluation and optimal parameters for ballast water treatment methods.

Trash to Treasure: From Harmful Algal Blooms to High-Performance Electrodes for Sodium-Ion Batteries.

Harmful algal blooms (HABs) are frequently reported around the globe. HABs are typically caused by the so-called blue-green algae in eutrophic waters. These fast-growing HABs could be a good source for biomass. Unlike terrestrial plants, they need no land or soil. If HABs could be harvested on a large scale, it could not only possible to mitigate the issue of HABs but also provide a source of biomass. Herein, we demonstrate a facile procedure for converting the HABs into a promising high-performance negative-electrode material for sodium-ion batteries (SIBs). The carbon material derived from blue-green algae demonstrated promising electrochemical performance in reversible sodium storage. The algae used in this work was collected directly from Lake Erie during the algal blooms that affected 500 000 residents in Toledo in 2014. The carbon, derived from the freshly collected HABs by calcination in argon without any additional purification process, delivered a highly stable reversible specific capacity (∼230 mAh/g at a testing current of 20 mA/g) with nearly 100% Columbic efficiency in sodium storage. Impressive rate performance was achieved with a capacity of ∼135 mAh/g even after the testing current was increased fivefold. This proof of concept provides a promising route for mitigating the issue of HABs as "trash" and for generating high-capacity, low-cost electrodes for SIBs as "treasure".

Alkaline and Acid Catalyzed Transesterification Bioprocess in Biodiesel Preparation from Fresh Water Algae

Alkaline and Acid Catalyzed Transesterification Bioprocess in Biodiesel Preparation from Fresh Water Algae

Hydrothermal conversion of Ulva macro algae in supercritical water

Ulva (Ulva armoricana and Ulva rotundata) are macro algae which are responsible of environmental damages and are a cause of an eutrophication of the water in the French coast (Mediterranean sea, Brittany). In this study, Ulva were gasified in supercritical water in a batch reactor and in Hydrothermal Diamond Anvil Cell apparatus. Experimental conditions evolve between 400 and 550°C at around 250bar. Results show that a short time (7min) in supercritical condition is sufficient to obtain a significant conversion rate. H2 and CH4 concentrations exceed 15mol.% at high temperature (550°C) and high algae concentrations are not favorable for H2 production. The solid residue represents between 7 and 20wt.% of the initial dry material and is mainly constituted of carbon (20wt.%) and inorganic compounds: salts (KCl, NaCl), CaSO4, SiO2 and CaCO3. The very low dissolved organic carbon (DOC) values of the liquid residue (<0.4wt.%) confirm the high gasification rates. Thiophenes, pyridines, and pyrazines were detected in the liquid phase. Hydrothermal Diamond Anvil Cell (HDAC) experiments were performed to observe gasification stages at the supercritical state.

Effect of Salt Stress on Growth, Antioxidant Enzymes, Lipid Peroxidation and Some Metabolic Activities in Some Fresh Water and Marine Algae

Effect of Salt Stress on Growth, Antioxidant Enzymes, Lipid Peroxidation and Some Metabolic Activities in Some Fresh Water and Marine Algae

Wireless Remote Central Monitoring System for Freshwater Lakes

The management of water resources is closely related to human life. Thus the operation of various devices for water circulation, algae control and water quality control of scattered freshwater lakes is paramount. In this paper, the author designed and implemented a system which monitors water quality in real time. The subjects for monitoring include amount of sunlight collected from various types of photovoltaic inverters, power consumption and data from water quality analysis sensors, e.g. temperature, hydrogen-iron concentration (pH), amount of dissolved oxygen (DO), electrical conductivity (EC), chlorophyll-a (Chl-a), and turbidity. These were accumulated in a BD server on a real-time basis. By using this data, the author developed a system which facilitates real-time integrative monitoring and transmits an SMS alert in the event of an emergency. The suggested system is able to reduce time and manpower because there is no need to visit sites to measure the water quality, thereby increasing efficiency of water quality management and preventing disasters through real-time monitoring of water quality and swift reaction.

The combined and second exposure effect of copper (II) and chlortetracycline on fresh water algae, Chlorella pyrenoidosa and Microcystis aeruginosa

In the experiment, Chlorella pyrenoidosa and Microcystis aeruginosa were chosen to test the individual, combined and second exposure effect of Cu2+ and chlortetracycline (CTC). The 96h EC50s of each test were calculated, with the ranges of 0.972–15.6μmol/L (Cu2+), 29.5–102.5μmol/L (CTC), 14.4–78.9μmol/L (mixture). The combined toxicities were evaluated with toxicity units (TU) method. The toxicity of complex of Cu2+ and chlortetracycline was analyzed using concentration addition (CA) model. In the initial test, the combined effect of the two substances was partly additive to C. pyrenoidosa and antagonistic to M. aeruginosa, while in the second exposure test, the combined effect was synergistic to both algae. The biochemical indicators measured in the experiment included chlorophyll fluorescence (Fv/Fm), MDA content, SOD activity and content of soluble proteins. When under combined stress, the biochemical features of both algae were significantly different between the initial test and the second exposure test.

Mercury (Hg) speciation in coral reef systems of remote Oceania: Implications for the artisanal fisheries of Tutuila, Samoa Islands

We investigated Hg in muscle tissue of fish species from three trophic levels on fringing reefs of Tutuila (14°S, 171°W), plus water, sediment and turf alga. Accumulation of total Hg in the herbivore Acanthurus lineatus (Acanthuridae, lined surgeonfish, (n=40)) was negligible at 1.05 (±0.04) ngg−1 wet-weight, (∼65% occurring as methyl Hg). The mid-level carnivore Parupeneus spp. (Mullidae, goatfishes (n=10)) had total Hg 29.8 (±4.5) ngg−1 wet-weight (∼99% as methyl Hg). Neither A. lineatus or Parupeneus spp. showed a propensity to accumulate Hg based on body size. Both groups were assigned a status of “un-restricted” for monthly consumption limits for non-carcinogenic health endpoints for methyl Hg. The top-level carnivore Sphyraena qenie (Sphyraenidae, blackfin barracuda, n=3) had muscle tissue residues of 105, 650 and 741ngg−1 wet-weight (100% methyl Hg, with increasing concentration with body mass, suggesting that S. qenie >15kg would have a recommendation of “no consumption”.

Compound Piezomechanical Systems of Algae Cell Disrupting

Abstract One of the most attractive sources of raw materials for biofuel production can be algae oil processing into biofuels. In this paper, the authors are proposing a unique ultrasonic piezoelectric system, which would allow the reduction of internal energy losses and concentration of ultrasonic energy into a small closed volume. The current vibrating systems whose ultrasonic energy is concentrated inside of a hollow cylinder where the water–algae mixture is flowing. The ultrasonic energy is concentrated in a local volume to create a high-power bubble implosion process. Two, three or multiple ultrasonic composite systems to concentrate the total energy into a hollow cylinder in order to create a strong algae cell ultrasonication are used. The experiments and the numerical finite element method (FEM) analysis results using the proposed transducers as well as the biological test results on algae cell disruption by ultra-sonication are presented in this paper.