Arthrospira Fusiformis Research Articles

Spatiotemporal distribution of cyanobacteria in relation to water chemistry of Sutlej River, Punjab (India).

In this investigation, the spatiotemporal distribution of cyanobacteria and their relationships with variations in water chemistry (physico-chemical parameters and heavy metal) of Sutlej River, Punjab (India) has been analyzed by employing multivariate statistical methods. Sutlej River exhibits a rich array of cyanobacterial diversity, comprising 28 species across 15 genera, distributed among 11 families and spanning 5 orders within the class Cyanophyceae. In terms of relative abundance, Microcystis aeruginosa (17.47%) was documented as the most abundant taxa followed by Microcystis robusta (16.55%), Merismopedia punctata (11.03%), Arthrospira fusiformis (6.67%) and Pseudanabaena galeata (3.68%). Significant variations were observed among sampling sites in most of the physico-chemical parameters. Principal Component Analysis delineated sampling sites into two discernible groups according to variations in water chemistry. River Pollution Index (RPI) showed that river water is under the unpolluted (RPI 1.5) to negligibly polluted category in the upstream sites, while moderately polluted (RPI 5.5) in the downstream sites. Heavy metal Pollution Index (HPI) revealed consistent heavy metal contamination at sites RWS7 and RWS8 across all seasons. Conversely, site RWS1 consistently exhibited lower HPI values throughout the three studied seasons. Further, Canonical Correspondence Analysis identified that pH, TDS, TA, NO3, Na, and NH4 are the key physicochemical parameters which affect the spatiotemporal distribution of cyanobacteria in the studied river system. Overall, this study will offer significant information for hydrologists, ecologists, and taxonomists to develop future holistic strategies for further monitoring of the Sutlej River and other similar habitats.

Phytoplanktonic species in the haloalkaline Lake Dziani Dzaha select their archaeal microbiome.

Microorganisms are key contributors of aquatic biogeochemical cycles but their microscale ecology remains largely unexplored, especially interactions occurring between phytoplankton and microorganisms in the phycosphere, that is the region immediately surrounding phytoplankton cells. The current study aimed to provide evidence of the phycosphere taking advantage of a unique hypersaline, hyperalkaline ecosystem, Lake Dziani Dzaha (Mayotte), where two phytoplanktonic species permanently co-dominate: a cyanobacterium, Arthrospira fusiformis, and a green microalga, Picocystis salinarum. To assay phycospheric microbial diversity from insitu sampling, we set up a flow cytometry cell-sorting methodology for both phytoplanktonic populations, coupled with metabarcoding and comparative microbiome diversity. We focused on archaeal communities as they represent a non-negligible part of the phycospheric diversity, however their role is poorly understood. This work is the first which successfully explores insitu archaeal diversity distribution showing contrasted phycospheric compositions, with P. salinarum phycosphere notably enriched in Woesearchaeales OTUs while A. fusiformis phycosphere was enriched in methanogenic lineages affiliated OTUs such as Methanomicrobiales or Methanofastidiosales. Most archaeal OTUs, including Woesearchaeales considered in literature as symbionts, were either ubiquitous or specific of the free-living microbiome (i.e. present in the 3-0.2 μm fraction). Seminally, several archaeal OTUs were enriched from the free-living microbiome to the phytoplankton phycospheres, suggesting (i) either the inhibition or decrease of other OTUs, or (ii) the selection of specific OTUs resulting from the physical influence of phytoplanktonic species on surrounding Archaea.

Spirulina (Arthrospira fusiformis, Gomont 1892) as a High-Quality Feed Ingredient for Nile Tilapia Fingerlings

A partially randomized experimental design was conducted to evaluate the effect and potential of spirulina species (Arthrospira fusiformis) isolated from Momela Lakes, Tanzania, on the growth, antioxidant capacity, feed utilization, and body composition of Nile tilapia fingerlings. Five dietary treatments were formulated, including spirulina meal at 5%, 10%, and 15% of the total diets, as well as control diets with freshwater shrimp or Lake Victoria sardine. The protein content of the experimental diets was 25, 28, and 35% for a treatment containing spirulina at 5, 10, and 15% inclusion, respectively, while the control diets had 35% crude protein each. After eight weeks of feeding, fish fed with a lower inclusion level of spirulina showed the best growth performance and feed utilization efficiency, similar to the fish fed with control diets. The group fed with 5% spirulina exhibited excellent protein efficiency ratio compared to all other fish groups. All spirulina-fed fish groups demonstrated higher protein deposition and strong antioxidant activity against free radicals compared to those fed with control diets. In conclusion, spirulina proves to be a superior feed ingredient for high-quality Nile tilapia farming, providing comparable results to control feeds.

Volatile Compounds, Fatty Acids Constituents, and Antimicrobial Activity of Cultured Spirulina (Arthrospira fusiformis) Isolated from Lake Mariout in Egypt.

In this study, Arthrospira fusiformis previously isolated from Lake Mariout (Alexandria, Egypt) was cultivated in the laboratory using a medium for pharmaceutical grade Arthrospira, named as Amara and Steinbüchel medium. Hot water extract of the Egyptian Spirulina was prepared by autoclaving dried biomass in distilled water at 121°C for 15 min. This algal water extract was analyzed by GC-MS to evaluate its volatile compounds and fatty acids composition. The antimicrobial activity of phycobiliprotein extract from Arthrospira fusiformis using phosphate buffer was evaluated against thirteen microbial strains (two Gram-positive bacteria, eight Gram-negative bacteria, one yeast, and two filamentous fungi). The major components of fatty acids in the hot extract of Egyptian A. fusiformis were hexadecanoic acid (palmitic acid, 55.19%) and octadecanoic acid (stearic acid, 27.14%). The main constituents of its volatile compounds were acetic acid (43.33%) and oxalic acid (47.98%). The most potent antimicrobial effect of phycobiliprotein extract was obtained against two Gram-negative bacteria Salmonella typhi and Proteus vulgaris, filamentous fungus Aspergillus niger, and the pathogenic yeast Candida albicans (all of which showed MIC values of 58.1 μg/ml). Escherichia coli and Salmonella typhimurium come second in their susceptibility to the phycobiliprotein extract from Arthrospira fusiformis and Serratia marcescens and Aspergillus flavus are the least in susceptibility, with MIC values of 116.2 and 232.5 μg/ml, respectively, while phycobiliprotein extract has no antibacterial effect on methicillin-resistant as well as susceptible Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Shigella sonnei. These findings confirmed the nutritional value of Egyptian A. fusiformis isolated from Lake Mariout and suggest the potential use of this strain as an ingredient in the cooking of some foods to increase the level of stearic acid and palmitic acid. Moreover, its effective antibacterial activities against some important and highly resistant to antibiotics bacterial pathogens in addition to its antifungal effects recommend the therapeutic use of its biomass.

DISCOVR strain pipeline screening – Part I: Maximum specific growth rate as a function of temperature and salinity for 38 candidate microalgae for biofuels production

To identify high productivity strains for microalgal biofuels generation, the maximum specific growth rate of 38 strains was measured as a function of salinity (i.e., 5, 15, and 35 PSU) and temperature (i.e., at 8 temperatures along a linear gradient from ca. 5 to 45 °C) to determine the most suitable growth medium salinity and best growing season, respectively, for outdoor raceway pond cultivation. The following strains were evaluated: Agmenellum quadruplicatum UTEX 2268, Anabaena sp. ATCC 33081, Arthrospira fusiformis UTEX 2721, Arthrospira platensis UTEX 3086, Chlorella vulgaris NREL 4-C12, Chlorella autotrophica CCMP 243, Chlorella sorokiniana DOE1044, Chlorella sorokiniana DOE 1116, Chlorella sorokiniana DOE 1412 (UTEXB3016), Chlorella vulgaris LRB AZ-1201, Chlorococcum littorale UTEX 117, Chlorococcum sp. UTEX-B P7, Chloromonas reticulata CCALA 870, Coelastrella sp. DOE 0202, Cyanobacterium sp. AB1, Micractinium reisseri NREL 14-F2, Microchloropsis gaditana CCMP1894, Microchloropsis salina CCMP 1776, Monoraphidium sp. MONOR1, Monoraphidium minutum 26B-AM, Nannochloropsis oceanica CCAP 849/10, Oscillatoria cf. priestleyi CCMEE 5020.1-1, Picochlorum celeri TG2-WT-CSM/EMRE, Picochlorum oklahomensis CCMP 2329, Picochlorum renovo NREL 39-A8, Picochlorum soloecismus DOE 101, Porphyridium cruentum CCMP 675, Scenedesmus acutus LRB-AP-0401, Scenedesmus obliquus DOE 0152.z, Scenedesmus obliquus UTEX393,Scenedesmus rubescens NREL 46B-D3, Scenedesmus sp. IITRIND2, Stichococcus minor CCMP 819, Stichococcus minutus CCALA 727, Synechococcus elongatus UTEX2973.1, Tetraselmis striata LANL 1001, Tisochrysis lutea CCMP 1324, and Tribonema minus UTEXB3156. For each strain, the identity and the presence of bacterial cohorts was determined using 18S and 16S rDNA sequencing, respectively. The maximum specific growth rate versus temperature data were also used to determine the activation energies (Arrhenius equation) for most strains. For all strains, the measured salinity and temperature tolerance data were compared to those reported in the literature. The fastest growing strains were down-selected for subsequent biomass productivity measurements in climate-simulation photobioreactors, as reported in the next paper in the issue.

Free ammonia tolerance of cyanobacteria depends on intracellular pH

Algae-based wastewater treatment can remove nutrients from wastewater and simultaneously produce valuable products. However, inhibition of microalgae by NH3 in the wastewater poses a challenge to this process. It is desirable to understand the mechanism of inhibition by NH3 for physiological characterization of microalgae and their application. NH3 tolerance, which varies among species, is assumed to depend on intracellular pH. To verify the adequacy of the assumption, in this study, the 50% inhibitory concentration (EC50) of NH3 for four cyanobacterial species was evaluated as an indicator of NH3 tolerance and compared to intracellular pH. The EC50 of NH3 was 4.95, 5.05, 4.38, and 0.74 mM and the intracellular pH was 8.0, 8.4, 8.2, and 7.3 for Arthrospira platensis, Arthrospira fusiformis, Synechococcus leopoliensis, and Anabaena cylindrica, respectively. A significant correlation was obtained between intracellular pH and EC50. Analysis of the chlorophyll fluorescence of cells exposed to NH3 for 1.5 h showed that photochemical quenching was reduced rather than Fv'/Fm' under NH3 concentrations lower than EC50, suggesting that the electron transfer system downstream of photosystem II (PSII) was more sensitive than PSII itself. Because several sites downstream of PSII utilize H+, including ATP synthase, the inhibition may be caused as a result of H+ consumption by NH3 diffused inside the cells. As consumption of H+ in NH3 ionization is suppressed under high pH, species with higher intracellular pH probably have higher NH3 tolerance. These results should help understand the free NH3 tolerance of cyanobacteria.

Diversity of Culturable Alkaliphilic Nitrogen-Fixing Bacteria from a Soda Lake in the East African Rift Valley.

Lake Chitu is a highly productive soda lake found in the East African Rift Valley, where Arthrospira fusiformis (Spirulina platensis) is the main primary producer. High biomass accumulation requires an adequate supply of nitrogen. However, Lake Chitu is a closed system without any external nutrient input. A recent study has also demonstrated the presence of a diverse group of denitrifying bacteria, indicating a possible loss of nitrate released from the oxidation of organic matter. The aim of this study was to isolate culturable nitrogen-fixing alkaliphiles and evaluate their potential contribution in the nitrogen economy of the soda lake. A total of 118 alkaliphiles belonging to nine different operational taxonomic units (OTUs) were isolated using a nitrogen-free medium. Nineteen isolates were tested for the presence of the nifH gene, and 11 were positive. The ability to fix nitrogen was tested by co-culturing with a non-nitrogen-fixing alkaliphile, Alkalibacterium sp. 3.5*R1. When inoculated alone, Alkalibacterium sp. 3.5*R1 failed to grow on a nitrogen-free medium, but grew very well when co-cultured with the nitrogen-fixing alkaliphile NF10m6 isolated in this study, indicating the availability of nitrogen. These results show that nitrogen fixation by alkaliphiles may have an important contribution as a source of nitrogen in soda lakes.

Smart Production of Lipids as Bio-Fuel in Spirulina Platensis (=Arthrospira Fusiformis), and Bio-Oxygen and Bio-Electricity in Media Cultured in Supernatant of Digested Poultry Waste

An experiment was conducted to evaluate growth performances and production of bio-fuel of Spirulina platensis (Gomont), and bio-oxygen and bio-electricity of culture media in supernatant of three different amount of digested poultry waste (DPW), and Kosaric medium (KM) as control. Three different amounts (concentrations) such as 2.0, 4.0 and 6.0 g/L poultry waste were allowed to digest under aeration. After 17 days, 700 ml grayish coloured supernatant was taken with addition of 9.0 g/L NaHCO3 and 0.50 ml/l micronutrient in 2.0 L conical flask with three replications and then autoclaved. Spirulina was inoculated to grow in these three treatments including KM (Control) after 72 hours of autoclave and then allowed to grow for a period of 14 days. This duration was estimated through repeated growth trials. The cell weight of spirulina was attained a maximum of 12.58 ± 1.25 mg/L (dry wt. basis) in KM followed by 11.46 ± 1.03, 9.16 ± 0.84 and 8.13 ± 0.73 mg/L in supernatant of 4.0, 2.0 and 6.0 g/L DPW, respectively on the 10th day of culture. Similar trend was also observed in the cases of optical density of the media contained spirulina, chlorophyll a content (mg/L), cell weight, total biomass (mg/l) and specific growth rates on the basis of cell weight and chlorophyll a. Cell weight of spirulina grown in these media had highly significant (P < 0.01) correlation with the chlorophyll a content (r = 0.993) of spirulina. Crude protein of spirulina grown in supernatant of DPW was lower than that of spirulina cultured in KM. Crude lipids as bio-fuel of spirulina cultured in supernatant of 4.0 g/L DPW was almost three times higher than that of spirulina grown in KM which may be due to high phospholipids bioaccumulation. Phosphate-P was decreased in media of DPW due to its use for high lipids biosynthesis as phospholipids. Bio-oxygen was produced higher ranged from 2.1 ± 11 mg/L on initial day to 10.20 ± 0.54 mg/L on 10th day grown in supernatant of 4.0 g/L DPW media. Bio-electricity as green electricity ranged from 135 ± 4 on initial day to 284 ± 7 mV on 10th day when spirulina cultured in supernatant of 4.0 g/L DPW which was higher than grown in other media. pH followed the similar trend like bio-oxygen and bio-electricity. It was found that the production of bio-oxygen, bio-fuel and bio-electricity had direct relation with pH in culture media of spirulina. Therefore, mass production of Spirulina platensis might be done in supernatant of 4.0 g/L digested poultry waste to get high total lipids as bio-fuel, bio-electricity and bio-oxygen.

Utilization of Cyanobacteria Extracts in Improving the Microbial Quality of Soft White Cheese

The current study was evaluated to determine the prevalence of Escherichia coli and Staphylococcus aureus in raw milk in addition to some dairy products which are sold in Dakahlia Governorate, Egypt. Hundred and fifty samples including raw milk, soft cheese (Talaga cheese), kariesh cheese; Ras cheese (Romy), ice cream and yoghurt. (25 samples from each product) were collected and then subjected to bacterial examination. In order to identify recovered isolates, an array of biochemical and polymerase chain reaction (PCR) was used. Our results detected that E. coli was noticed in 68%, 56%, 88%, 68%, 52% and 80% of raw milk, soft cheese (Talaga cheese), kariesh cheese; Ras cheese (Romy), ice cream and yoghurt, respectively. The prevalence of S. aureus was detected in 52%, 88%, 80%, 76%, 28% and 52%, respectively. The results showed that the aqueous extracts of the cyanobacteria such as Sprirulina plantensis and Arthrospira fusiformis were evaluated for their antibacterial activity by inhibiting the growth of E. coli and S. aureus.The soft cheese treated with cyanobacteria extract and wrapped with banana leaves showed a potentially reduction of bacterial contamination than that wrapped with plastic material. The results proved that the using these species of cyanobacteria could be used a good source for the production of promising antibacterial agents.

Biomass and nutritive value of Spirulina (Arthrospira fusiformis) cultivated in a cost-effective medium

IntroductionCultivation of spirulina at commercial-scales relies on analytical grade–based media, which are expensive and so are the product.PurposeThis study assessed the biomass, proximate composition, and other useful compounds in Spirulina (Arthrospira fusiformis) produced with a cost-effective culture medium (LCMA), and the results were compared with those from a standard Zarrouk medium–grown spirulina.MethodsThe LCMA medium was formulated by using a commercial NPK10-20-20 fertilizer as a source of the three major nutrients for spirulina growth, and other three ingredients from Zarrouk medium. The experiment was conducted for 28 days in the glass aquaria under indoor conditions. Standard analytical methods were applied for the determination of proximate composition, chlorophyll, minerals, and vitamins in the spirulina biomass.ResultThe LCMA medium showed the best growth conditions by accumulating higher chlorophyll content (0.99 ± 0.02%) and dry weight (0.75 ± 0.01 g/100 ml) as well as attaining higher optical density (2.06 at day 15) earlier than the Zarrouk medium. The results of the proximate analysis for spirulina cultured in the LCMA medium were of good quality, with the protein contributing more than 50% of its dry matter. It was further noticed that the LCMA was an ideal medium for optimization of vitamins and some minerals since it recorded a significant amount of most of the analyzed vitamins together with the minerals sodium and potassium compared with the Zarrouk medium.ConclusionIt is suggested that LCMA medium could be used as the alternative and cheap medium for maximization of biomass and production of useful biochemical compounds in spirulina species.

Spirulina (Arthrospira fusiformis) as a potential protein source in practical diets for fry mariculture of Rufiji tilapia (Oreochromis urolepis urolepis)

The effects on growth performance, feed utilization, survival and whole fish body proximate composition of replacing fishmeal (Rastrineobola argentea) with a locally available spirulina species (Arthrospira fusiformis) as a protein ingredient in the feed of Rufiji tilapia (Oreochromis urolepis urolepis) fry was examined. Fishmeal replacement with A. fusiformis was carried out at 5%, 15%, 25%, 35% and 100% (S5, S15, S25, S35 and S100), and the effect of the replacement was compared with the control diet (S0, 0% spirulina). Fish fry were stocked at an average initial weight of 0.57 g at 10 fish per 0.1 m3 and cultured for 60 days using full strength salt water (30-35 ppt). A. fusiformis was isolated from Momela Lake in Arusha National Park, Tanzania and propagated using selected culture media. It was observed that fish fry fed spirulina at a 5% fishmeal substitution level diet had better (p<0.05) final weight (8.48), average daily weight gain (0.132), specific growth rate (4.47), feed conversion rate (2.08) and protein efficiency ratio (1.37) compared to the control fish group. Growth performance in fish fed diet S15 was comparable with the control group (p>0.05). Spirulina supplementation had no effect on fish survival rates and meat quality. It appears that the Momella Lake spirulina may be an appropriate growth-stimulating plant protein when used as a feed additive in Rufiji tilapia mariculture.

Biomass production and growth performance of Momela Lake’s spirulina (<i>Arthrospira fusiformis</i>) cultured under urea and N: P: K fertilizers as cheaper nitrogen sources

Spirulina species are world widely known for their ability to produce high quantities of useful metabolites such as protein, fatty acids and vitamins. One of the major challenges in production of this microalgae is the cost and composition of culture medium. In the present study, effect of two culture media with agricultural fertilizers as nitrogen sources viz. urea containing medium (UM) and N: P: K containing medium (NPKM) on production of a locally found spirulina (Arthrospira fusiformis) was investigated. Zarrouk medium (ZM) was used as a standard, other culture conditions included 67.5 μmol m-2 s-1 radiation, 10 pH and 30 ºC temperature. A. fusiformis was isolated from Momela Lake in Arusha National Park Tanzania. There was no difference (p > 0.05) in mean biomass production (BMmean) and doubling time (DT) between ZM (1.205 g/L, 1.437 days respectively) and UM (1.168 g/L, 1.63 days respectively). Significantly higher (p < 0.05) maximum biomass BMmax production and exponential growth rate (μ) in a sequential order was from ZM (1.844 g/L, 0.483/day respectively), UM (1.6 g/L, 0.425/day respectively) and NPKM (0.57 g/L, 0.273/day). It appeared that the wild-isolated A. fusiformis was able to grow well in less costly UM showing high potential for mass production.© 2019 International Formulae Group. All rights reserved.Keywords: Momela Lake’s spirulina, biomass production, agricultural fertilizers, nitrogen sources

Very Low Phytoplankton Diversity in a Tropical Saline-Alkaline Lake, with Co-dominance of Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta)

Lake Dziani Dzaha (Mayotte Island, Indian Ocean) is a tropical thalassohaline lake which geochemical and biological conditions make it a unique aquatic ecosystem considered as a modern analogue of Precambrian environments. In the present study, we focused on the diversity of phytoplanktonic communities, which produce very high and stable biomass (mean2014–2015 = 652 ± 179 μg chlorophyll a L−1). As predicted by classical community ecology paradigms, and as observed in similar environments, a single species is expected to dominate the phytoplanktonic communities. To test this hypothesis, we sampled water column in the deepest part of the lake (18 m) during rainy and dry seasons for two consecutive years. Phytoplanktonic communities were characterized using a combination of metagenomic, microscopy-based and flow cytometry approaches, and we used statistical modeling to identify the environmental factors determining the abundance of dominant organisms. As hypothesized, the overall diversity of the phytoplanktonic communities was very low (15 OTUs), but we observed a co-dominance of two, and not only one, OTUs, viz., Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta). We observed a decrease in the abundance of these co-dominant taxa along the depth profile and identified the adverse environmental factors driving this decline. The functional traits measured on isolated strains of these two taxa (i.e., size, pigment composition, and concentration) are then compared and discussed to explain their capacity to cope with the extreme environmental conditions encountered in the aphotic, anoxic, and sulfidic layers of the water column of Lake Dziani Dzaha.

Availability and Nutritive Value of Spirulina (<i>Arthrospira fusiformis</i>) from Arenguade and Chitu Lakes of Rift Valley of Ethiopia and Farmers’ Perception about Its Utilization

Farmers perception about availability and utilization of Spirulina (Arthrospira fusiformis) were assessed and its nutritive value compared against reference proteins (soybean and nuge cake). Samples of Spirulina were collected from Arenguade and Chitu lakes of rift valley of Ethiopia. A survey was conducted on purposively selected 100 households (HH) living around the Lakes which are located in Gerbicha and Labu subuqa districts of Debre Zeit town and west Arsi zone, respectively. Chemical composition and in vitro dry matter digestibility (IVDMD) and total gas volume (TGV) of feed samples were determined. Respondents of both districts are not aware of Spirulina as animal feed. Spirulina was available during dry season in Arenguade and whole year in Chitu. The highest (p 0.05) in crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) and metabolizable energy (ME) contents between Spirulina from both lakes. Spirulina from Chitu produced the highest TGV (31.2 ml) and fermented faster than Spirulina from Arenguade. Lowest (p < 0.05) ash, EE, CP and IVDMD and higher (p < 0.05) CF, NDF, ADF, ADL and TGV were recorded for reference proteins than Spirulina. ME content of Spirulina (3200 kcal/kg) was higher (p < 0.05) than that of nuge cake (3011 kcal/kg) but lower (p < 0.05) than that of soybean (3474 kcal/kg). Therefore, the chemical composition and IVDMD showed the potential of Spirulina to be used as a substitute of the reference feeds.

Bioaccumulation of trace elements in Arthrospira fusiformis algal blooms in Lakes Bogoria and Sonachi, Kenya: Evaluation and verification of toxicokinetic models

AbstractThe bioaccumulation of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) was examined in Arthrospira fusiformis algal blooms. The present study was designed to provide information on accumulation strategies of the test organism and to verify two‐compartment toxicokinetic models as predictive tools. Heavy metal accumulation in the organisms did occur, and it was possible to estimate significant model parameters of two‐compartment models. The nominal exposure was a metal mixture of 0.005, 0.03, 0.02 and 0.06 μg/g of Cd, Cu, Pb and Zn, respectively, being doubled and tripled in subsequent experiments. The experiment design was a semi‐static system comprising five hours for uptake and a similar duration for clearance. The design comprised two replicates and a control. Cd and Cu produced better models (R2 &gt; 0.5), compared to Pb and Zn. Concurrent uptake rate constants (k1) were higher than the elimination rate constants (k2), leading to net accumulation. The t‐values for parameter estimates were ≥2, indicating the estimates were statistically different from zero. Kinetic bioconcentration factors (BCFs) at theoretical equilibrium increased with increased exposure doses, especially for Cu. Time‐dependent model parameters were verified with independent experimental data to assess reproducibility. Cd and Cu models were verifiable, especially when the experiments were for the same environmental medium/lake. Time‐dependent model parameters were verified with data from concentration‐dependent exposures, indicating the models were verifiable, exhibiting better agreement when the model parameters and test data were from the same lake. Specific trace elements accumulation strategies for the test organism, Arthrospira fusiformis, the main food organism for flamingos in the studied lakes, can be useful in interpreting trophic transfers, noting flamingos in those lakes must be conserved because they are a tourist attraction, thereby being of significant economic benefit to the citizens and government of Kenya.

Characterization of phototrophic microorganisms and description of new cyanobacteria isolated from the saline-alkaline crater-lake Dziani Dzaha (Mayotte, Indian Ocean).

The saline-alkaline crater-lake Dziani Dzaha (Mayotte, Indian Ocean) is dominated by the bloom-forming cyanobacterium Arthrospira. However, the rest of the phototrophic community remains underexplored because of their minute dimension or lower biomass. To characterize the phototrophic microorganisms living in this ecosystem considered as a modern analog of Precambrian environments, several strains were isolated from the water column and stromatolites and analyzed using the polyphasic approach. Based on morphological, ultrastructural and molecular (16S rRNA gene, 18S rRNA gene, 16S-23S internal transcribed spacer (ITS) region and cpcBA-IGS locus) methods, seven filamentous cyanobacteria and the prasinophyte Picocystis salinarum were identified. Two new genera and four new cyanobacteria species belonging to the orders Oscillatoriales (Desertifilum dzianense sp. nov.) and Synechococcales (Sodalinema komarekii gen. nov., sp. nov., Sodaleptolyngbya stromatolitii gen. nov., sp. nov. and Haloleptolyngbya elongata sp. nov.) were described. This approach also allowed to identify Arthrospira fusiformis with exclusively straight trichomes instead of the spirally coiled form commonly observed in the genus. This study evidenced the importance of using the polyphasic approach to solve the complex taxonomy of cyanobacteria and to study algal assemblages from unexplored ecosystems.

Plankton composition, biomass, phylogeny and toxin genes in Lake Big Momela, Tanzania

Lake Big Momela, one of the East African soda lakes in Northern Tanzania characterised by highly saline-alkaline conditions, making them inhospitable to a range of organisms, although supporting massive growths of some adapted planktonic microorganisms that serve as food for birds, such as Lesser Flamingo. The temporal dynamics of plankton, with an emphasis on cyanobacteria, were examined in 2007 using morphological traits and ribosomal genetic markers (16S and 18S rRNA). Cyanobacterial genes encoding for hepatotoxins (mcyE and ndaF) were also screened. Rotifers and copepods dominated the zooplankton, whereas cyanobacteria, such as Anabaenopsis elenkinii and Arthrospira fusiformis dominated the phytoplankton community, and these being related to representatives in other East African soda lakes. The cyanobacteria community also showed distinct seasonal patterns influenced by environmental parameters, mainly salinity, pH and nitrate. Significant positive correlations were found between phytoplankton abundance and nitrate concentrations (r = 0.617, p = 0.033). No signals of the hepatotoxin synthetase genes mcyE and ndaF were retrieved from cyanobacteria during the whole year. In general, our data illustrate the presence of rich planktonic communities, including some unique and potentially endemic cyanobacteria.

Tackling community undernutrition at lake Bogoria, Kenya: The potential of spirulina (Arthrospira fusiformis) as a food supplement

Undernutrition remains a major public health concern for many developing nations, particularly in sub-Saharan Africa. In Kenya, undernutrition affects a substantial portion of the Kenyan population, especially children and those living in rural areas. Local and sustainable means of addressing undernutrition is still lacking in many communities in urban, but more so in rural areas of Kenya. Spirulina ( Arthrospira fusiformis ), a cyanobacterium from alkaline inland waters, high in nutrient content, is a potential means of treating undernutrition in the developing world, where it can be easily grown. This paper presents a feasibility study on the harvest of Spirulina from Lake Bogoria in the Kenyan Rift Valley for use as a food supplement for undernutrition mitigation in the surrounding rural communities. A nutrition survey revealed the local population to be deficient in a number of micronutrients, specifically vitamins E and B12 that could be provided through dietary supplementation with Spirulina. A sample of Spirulina was collected from Lake Bogoria and analyzed for nutrient content and the presence of toxins. It was found that Lake Bogoria Spirulina had a dry protein content of 14.6% and is a rich source of dietary iron, with an iron content of 1.86%. A toxicity analysis revealed that Lake Bogoria Spirulina contained 1.15ng/g of microcystins (a group of hepatotoxic small polypeptides produced by several strains of cyanobacteria), which is within levels safe for human consumption according to World Health Organization standards. It was concluded that Lake Bogoria Spirulina is an easily accessible source of food and has the potential to be a sustainable means for the Lake Bogoria community to tackle undernutrition. Finally, using the data gathered, consultation sessions were arranged with key community groups and members to discuss the feasibility and potential for incorporation of Spirulina into the local diet – an ongoing collaborative process between researchers and the community that has already been met with some success. Key words : Spirulina, food, diet, undernutrition, Bogoria, toxicity, microcystins, community, Landsat

Threats, Use and Management Interventions for Restoration of Lake Chitu West Arsi, Ethiopia

Lake Chitu is one of Ethiopian Flamingo Lakes known by single dominant blue green algal specie called Arthrospira fusiformis. A household questionnaire survey of respondents, key informants and focus group discussion were made in 2012 in Labu Subuqa kebele where lake Chitu is found to see major threats for general ecosystem disturbance, to see the use of the lake for the surrounding community and to identify major stakeholders for restoration and conservation of the lake in an integrated way. Results showed that deforestation of the catchment area is the main threat for the total degradation of the lake. Soil erosion occurred due to intensive loss of vegetation that increased the amount of silt in the lake. Deposition of animal debris and detergents are added to the lake because of human and cattle direct contact. The timely decrease in the size might be due to siltation. The community is using the lake only for washing clothes because of its alkalinity and soap nature. They also take bath on the hot spring that immediately comes from the edge of the lake that would eventually contaminate and change the nature of the lake. This study revealed that the community is not using the lake water only for the purpose of sanitation. Several stakeholders have been identified, consulted and participated on restoration of the lake biodiversity.

Algal communities of Kenyan soda lakes with a special focus on Arthrospira fusiformis

Soda lakes are simple in biodiversity, but due to their highly stochastic environmental dynamics unexpected shifts in species composition do occur. We studied key drivers for structuring phytoplankton communities and identified variables significantly influencing changes of Arthrospira fusiformis abundance in the Kenyan soda lakes, Nakuru and Bogoria. In both lakes, Arthrospira fusiformis dominated algal biomass, but in Nakuru, crashes of this taxon were recorded. The three variables sodium, pH and dry mass significantly contributed to the phytoplankton taxa pattern. Arthrospira was absent at highest turbidity and salinity levels, being outcompeted by the small, single-celled chlorophyte Picocystis salinarium. Picoplankton was in general connected to higher pH values and tended to occur anti-cyclic to Arthrospira. Overall, the abundance of A. fusiformis was influenced by the boundaries of habitat suitability, light penetration, grazers and cyanophages attacks.