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Cyanobacteria species identified in 2012-2013 at Karaoun Reservoir: a) Microcystis aeruginosa, b) Microcystis viridis, c) Microcystis ichthyoblabe, d) Anabaena spiroides, e) Anabaena circinalis, f) Radiocystis geminate, g) Pilgeria brasiliensis , h) Aphanizomenon ovalisporum and i) Oscillatoria tenuis.
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Eutrophication and toxic cyanobacterial blooms have become a worldwide environmental problem. The Carlson trophic state index (CTSI) is widely used for the classification of trophic conditions of fresh water bodies. The performance of the TriOS microFlu-blue probe in the field, for the measurement of in vivo phycocyanin fluorescence, was compared t...
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Context 1
... taken at 0.5 m, 5 m and 10 m during 2012-2013 for microscopic counting showed that cyanobacteria biovolume ranged between 0.01 and 8.8 mm3 L-1. The major blooming cyanobacteria were Aphanizomenon ovalisporum and Microcystis aeruginosa (Figure 2). Aphanizomenon ovalisporum bloomed on October 2012 and Microcystis aeruginosa on July 2013. ...
Context 2
... all these samples, more than 90 % of the cyanobacterial biovolume consisted either of Aphanizomenon ovalisporum and Microcystis aeruginosa. The comparison of these cyanobacterial biovolumes to their corresponding Trios phycocyanin measurements that were performed at field, at the same depth and date is presented in Figure 2. The results of this comparison show a strong linear relation between Trios phycocyanin concentration and total cyanobacteria biovolumes in Karaoun Reservoir, a R 2 value of 0.87 ( Figure 3). ...
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Koseze pond is an anthropogenic, shallow water body, located on the outskirts of Ljubljana and an important element in terms of the natural and cultural heritage of the city. It shows eutrophic to hypereutrophic status. Despite its biodiversity and the potential for massive development of toxic cyanobacteria, it is not included in the national moni...
A commercially available handheld spectroradiometer, the WISP-3, was assessed as a tool for monitoring freshwater cyanobacterial blooms for management purposes. Three small eutrophic urban ponds which displayed considerable within-pond and between-pond variability in water quality and cyanobacterial community composition were used as trial sites. O...
Citations
... It provides raw results in terms of PC concentration and its putative measuring range is between 0 and 200 μg/L with an accuracy of 0.02 μg/L. The probe has been used in several published studies (Kong et al., 2017;Fadel et al., 2015b), in which the obtained PC concentrations correlated strongly against the number of cyanobacterial cells R 2 = 0.7296 (Brient et al., 2008) and biovolumes R 2 = 0.73 (Bastien et al., 2011). On July 12th 2016, spectroradiometric measurements were taken for several stations, in synchronous with satellite overpass, using a field spectroradiometer (ASD FieldSpec 4) within a spectral range of 350 nm-2500 nm, with a 10°foreoptic, and according to the SeaWIFS protocol (Fargion and Mueller, 2000). ...
Satellite remote estimates of phycocyanin (PC) have become valuable for monitoring the quality of inland waters affected by harmful cyanobacterial blooms. In this study, we developed an algorithm for mapping turbidity as a proxy of PC content through Landsat 8 Operational Land Imager (OLI) data and in situ measurements. The chosen study site is Karaoun Reservoir, in Lebanon, a hypereutrophic freshwater body where turbidity is mostly driven by cyanobacteria. Satellite images were corrected for atmospheric effects with the 6S (Second Simulation of the Satellite Signal in the Solar Spectrum) code which proved to be more accurate than the DOS (Dark Object Subtraction) approach with R = 0.98 and R = 0.5, respectively. A strong relationship was found between turbidity and PC measurements (R = 0.92, R2 = 0.86), as well as between turbidity and the ratio of band 5 to band 4 of the OLI (R = 0.88, R2 = 0.77). Results reveal a promising performance of the algorithm for predicting PC concentrations with high correlations determined through simple linear regression analysis for both the calibration (R = 0.92, R2 = 0.85) and validation (R = 0.88, R2 = 0.78) periods. An application of the approach to a set of historical Landsat images revealed a time series of cyanobacterial bloom occurrence with high variation in surface area at the study site. The algorithm is considered to be suitable for retrieving cyanobacteria in highly eutrophic waters dominated by cyanobacteria where turbidity is mostly a function of the latter. This approach will improve monitoring cyanobacterial blooms on a spatial and timely basis.
... The degradation of water quality was announced by the appearance of Chrysosporum ovalisporum, a cylindrospermopsin (CYN) producing cyanobacterium. This species had annual fluctuations (in the last 5 years) where it appeared in May-June and disappeared in July probably due to the variations in water temperature [14]. During 2015, the occurrence of C. ovalisporum took place in mid-March and form a thick bloom in May-June with total exclusivity. ...
Cylindrospermopsin (CYN) phytotoxicity, was investigated on seeds and seedlings of tomato (Lycopersicon esculatum L.) and cucumber (Cucumis sativus L.), after irrigation by water contaminated with this toxin. Our results showed that seed germination was reduced after exposure to higher concentrations of CYN. The cucumber seeds were more resistant than tomato seeds to this toxin. The CYN affected also the growth and productivity of seedlings. A significant reduction in the length of stems, roots (principle and lateral) and the number and size of leaves, appeared on the seedlings exposed to CYNs. These morphological changes were associated with alterations in primary xylem as a result of the inhibition of root growth and the reduction of water absorption. In addition, altered metabolism of tomato and cucumber seedling exposed to CYNs was manifested by chlorosis and leaf necrosis following a reduction in the chlorophyll content, photosynthesis inhibition and induction of oxidative stress.
