Exploring micropollutant biotransformation in three freshwater phytoplankton species

Water safety and quality can be compromised by the proliferation of toxin-producing phytoplankton species, requiring continuous monitoring of water sources. This analysis involves the identification and counting of these species which requires broad experience and knowledge. The automatization of these tasks is highly desirable as it would release the experts from tedious work, eliminate subjective factors, and improve repeatability. Thus, in this preliminary work, we propose to advance towards an automatic methodology for phytoplankton analysis in digital images of water samples acquired using regular microscopes. In particular, we propose a novel and fully automatic method to detect and segment the existent phytoplankton specimens in these images using classical computer vision algorithms. The proposed method is able to correctly detect sparse colonies as single phytoplankton candidates, thanks to a novel fusion algorithm, and is able to differentiate phytoplankton specimens from other image objects in the microscope samples (like minerals, bubbles or detritus) using a machine learning based approach that exploits texture and colour features. Our preliminary experiments demonstrate that the proposed method provides satisfactory and accurate results.

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Extracellular phosphatase activity of freshwater phytoplankton exposed to different in situ phosphorus concentrations

Marine and Freshwater Research ◽

10.1071/mf04283 ◽

2005 ◽

Vol 56 (4) ◽

pp. 417 ◽

Cited By ~ 29

Author(s):

A. Ŝtrojsová ◽

J. Vrba ◽

J. Nedoma ◽

K. Ŝimek

Keyword(s):

Enzyme Activity ◽

Phosphatase Activity ◽

Microcystis Aeruginosa ◽

Image Cytometry ◽

Phosphorus Concentration ◽

Phytoplankton Species ◽

Freshwater Phytoplankton ◽

Fragilaria Crotonensis ◽

Species Specific

Extracellular phosphatase production and biomass change were investigated in phytoplankton species transplanted from the phosphorus-limited dam area of a eutrophic reservoir and exposed to the phosphorus-sufficient inflow part and vice versa. Extracellular phosphatase activity was studied using the enzyme-labelled fluorescence (ELF) technique, allowing for direct microscopic detection of enzyme activity and, moreover, its quantification using image cytometry. Several phytoplankton species (e.g. Anabaena planctonica, Microcystis aeruginosa, Fragilaria crotonensis, Ankyra ancora and Planktosphaeria gelatinosa) regulated phosphatase activity according to external phosphorus concentration. On the contrary, picocyanobacteria and several green algae (Coelastrum microporum, Crucigeniella sp., Pediastrum tetras, and Staurastrum planctonicum) did not produce extracellular phosphatases at all. The species-specific extracellular phosphatase activity of F. crotonensis, A. ancora, and P. gelatinosa ranged between 0.02 and 3.5 fmol μm−2 h−1.

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Wastewater treatment – adsorption of organic micropollutants on activated HTC-carbon derived from sewage sludge

Water Science & Technology ◽

10.2166/wst.2015.511 ◽

2015 ◽

Vol 73 (3) ◽

pp. 607-616 ◽

Cited By ~ 9

Author(s):

Frank Kirschhöfer ◽

Olga Sahin ◽

Gero C. Becker ◽

Florian Meffert ◽

Michael Nusser ◽

...

Keyword(s):

Wastewater Treatment ◽

Sewage Sludge ◽

Low Income ◽

Wastewater Treatment Plants ◽

Transformation Products ◽

Hydrothermal Carbonization ◽

Organic Content ◽

Low Income Countries ◽

Organic Micropollutants ◽

Wastewater Samples

Organic micropollutants (MPs), in particular xenobiotics and their transformation products, have been detected in the aquatic environment and the main sources of these MPs are wastewater treatment plants. Therefore, an additional cleaning step is necessary. The use of activated carbon (AC) is one approach to providing this additional cleaning. Industrial AC derived from different carbonaceous materials is predominantly produced in low-income countries by polluting processes. In contrast, AC derived from sewage sludge by hydrothermal carbonization (HTC) is a regional and sustainable alternative, based on waste material. Our experiments demonstrate that the HTC-AC from sewage sludge was able to remove most of the applied MPs. In fact more than 50% of sulfamethoxazole, diclofenac and bezafibrate were removed from artificial water samples. With the same approach carbamazepine was eliminated to nearly 70% and atrazine more than 80%. In addition a pre-treated (phosphorus-reduced) HTC-AC was able to eliminate 80% of carbamazepine and diclofenac. Atrazine, sulfamethoxazole and bezafibrate were removed to more than 90%. Experiments using real wastewater samples with high organic content (11.1 g m−3) succeeded in proving the adsorption capability of phosphorus-reduced HTC-AC.

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Impacts of pH and salinity on community composition, growth and cell morphology of three freshwater phytoplankton

Plant Science Today ◽

10.14719/pst.2021.8.3.1190 ◽

2021 ◽

Vol 8 (3) ◽

Author(s):

Shaswati Chaktraborty ◽

Dipalok Karmaker ◽

Md. Alimur Rahman ◽

Sukanto Chandra Bali ◽

Subroto K Das ◽

...

Keyword(s):

Climate Change ◽

Community Composition ◽

Cell Morphology ◽

Single Species ◽

The Other ◽

Total Biomass ◽

Phytoplankton Species ◽

Freshwater Phytoplankton ◽

Wide Range ◽

Impacts Of Climate Change

Impacts of climate change on phytoplankton species are very focusing issues nowadays. This research explored the probable impacts of different pH (pH 5.90 to 9.10) and salinity (0.60 to 3.0 ppt) concentrations on freshwater phytoplankton Chlorella vulgaris, Euglena granulata and Scenedesmus quadricauda. The initial community composition was 4:2:1 for the three taxa, which changed to 6:3:1, 6:2:1, 6:3.5:1 and 9:4:1 in pH 5.90, pH 9.10 and salinity 2.20 and 3.0 ppt respectively. E. granulata showed more tolerance in a wide range of pH (pH 5.90 to 8.30) based on growth rate studies. The other two species showed growth rates reduction gradually in changes with pH and salinity concentrations. Conspicuous changes of total biomass were seen in pH 5.90 and 9.10, and salinity 2.20 and 3.0 ppt conditions. Moreover, significant changes in cell morphology were found in pH 9.10 and 3.0 ppt salinity. The authors concluded that as group, the Chlorophytes were more susceptible than the diatom in these variable pH and salinity conditions, while S. quadricauda was comparatively more vulnerable as a single species.

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