scholarly journals The Effects of Environmental Contaminants on Freshwater Cyanobacteria

2021 ◽  
Author(s):  
◽  
Jenna Mumford
Keyword(s):  
New Zealand ◽  
Quantum Yield ◽  
Chlorophyll A ◽  
Environmental Conditions ◽  
Algal Blooms ◽  
Photosynthetic Performance ◽  
Pigment Content ◽  
Maximum Quantum Yield ◽  
Screening Assay ◽  
Significant Difference

<p>Cyanobacteria are photosynthetic prokaryotes with a cosmopolitan distribution and are key contributors to Earth’s primary production. In favourable conditions, some taxa have the ability to form dense algal blooms. When blooms are created by toxin-producing strains they can become a public health threat and may lead to deaths of wild and domestic animals. Different species and strains respond differently to environmental conditions and contaminants, and this thesis investigates the impacts of natural (microcystin, a hepatotoxic cyanotoxin) and anthropogenic (glyphosate) contaminants on cyanobacteria.  Some non-microcystin-producing cyanobacteria have the ability to sequester microcystin, one of them being the strain Cuspidothrix issatschenkoi CAWBG02, and the reason for this ability is unknown. This strain was supplemented with microcystin in a range of environmental conditions (temperature/light intensity combinations) to determine any impacts on fitness by measuring photosynthetic performance, growth, and pigment content (chlorophyll-a and phycocyanin). Microcystin supplementation at a concentration of 25 μg L-1 did not have an effect on growth or pigment content in C. issatschenkoi, and photosynthetic performance was also largely unaffected. Based on the results from this thesis, C. issatschenkoi does not acquire competitive advantages from microcystin sequestration due to the lack of effects on growth and photosynthetic functioning. Previous research has suggested that microcystin is used to suppress competitors, and a 33% decrease in maximum quantum yield was detected in one environmental condition (low temperature, intermediate light), however, there was no significant difference in all of the other conditions used. Therefore, the results from this study do not support the idea that microcystin is used to suppress competitors. Microcystin sequestration may be more beneficial to non-producing-strains within the same species as the toxin-producer (e.g. non-toxic M. aeruginosa).  Glyphosate and MCPA are two of the most commonly used herbicides in New Zealand and globally. These herbicides enter waterways through leaching and come into contact with non- target species. To determine whether these herbicides have an effect on freshwater cyanobacteria in New Zealand, a screening assay was carried out on fourteen strains. Further, the impacts on pigment content (chlorophyll-a and phycocyanin), growth, and photosynthetic performance in two toxic (Nodularia spumigena, Microcystis aeruginosa) and two non-toxic (Dolichospermum lemmermannii, Microcystis wesenbergii) strains were quantified. Growth rates were not impacted by MCPA in any of the fourteen cyanobacterial strains. Glyphosate impacted growth in seven of the fourteen strains, and response differed between strains even within a single species. In general, strains employing a colonial growth strategy were more tolerant to glyphosate in the screening assay. N. spumigena and M. wesenbergii were unaffected by glyphosate at the concentrations used in the functional analysis, and D. lemmermannii had decreased photosynthetic performance from glyphosate. Intermediate concentrations of glyphosate resulted in promotion of PSII functioning in M. aeruginosa, and high concentrations inhibited maximum quantum yield. The lack of significant impacts on M.wesenbergii and N. spumigena, as well as negative effects of PSII functioning in D. lemmermannii, suggest that glyphosate contamination in freshwaters may benefit toxic M. aeruginosa more than competing toxic and non-toxic species or strains.</p>

scholarly journals The Effects of Environmental Contaminants on Freshwater Cyanobacteria

2021 ◽  
Author(s):  
◽  
Jenna Mumford
Keyword(s):  
New Zealand ◽  
Quantum Yield ◽  
Chlorophyll A ◽  
Environmental Conditions ◽  
Algal Blooms ◽  
Photosynthetic Performance ◽  
Pigment Content ◽  
Maximum Quantum Yield ◽  
Screening Assay ◽  
Significant Difference

<p>Cyanobacteria are photosynthetic prokaryotes with a cosmopolitan distribution and are key contributors to Earth’s primary production. In favourable conditions, some taxa have the ability to form dense algal blooms. When blooms are created by toxin-producing strains they can become a public health threat and may lead to deaths of wild and domestic animals. Different species and strains respond differently to environmental conditions and contaminants, and this thesis investigates the impacts of natural (microcystin, a hepatotoxic cyanotoxin) and anthropogenic (glyphosate) contaminants on cyanobacteria.  Some non-microcystin-producing cyanobacteria have the ability to sequester microcystin, one of them being the strain Cuspidothrix issatschenkoi CAWBG02, and the reason for this ability is unknown. This strain was supplemented with microcystin in a range of environmental conditions (temperature/light intensity combinations) to determine any impacts on fitness by measuring photosynthetic performance, growth, and pigment content (chlorophyll-a and phycocyanin). Microcystin supplementation at a concentration of 25 μg L-1 did not have an effect on growth or pigment content in C. issatschenkoi, and photosynthetic performance was also largely unaffected. Based on the results from this thesis, C. issatschenkoi does not acquire competitive advantages from microcystin sequestration due to the lack of effects on growth and photosynthetic functioning. Previous research has suggested that microcystin is used to suppress competitors, and a 33% decrease in maximum quantum yield was detected in one environmental condition (low temperature, intermediate light), however, there was no significant difference in all of the other conditions used. Therefore, the results from this study do not support the idea that microcystin is used to suppress competitors. Microcystin sequestration may be more beneficial to non-producing-strains within the same species as the toxin-producer (e.g. non-toxic M. aeruginosa).  Glyphosate and MCPA are two of the most commonly used herbicides in New Zealand and globally. These herbicides enter waterways through leaching and come into contact with non- target species. To determine whether these herbicides have an effect on freshwater cyanobacteria in New Zealand, a screening assay was carried out on fourteen strains. Further, the impacts on pigment content (chlorophyll-a and phycocyanin), growth, and photosynthetic performance in two toxic (Nodularia spumigena, Microcystis aeruginosa) and two non-toxic (Dolichospermum lemmermannii, Microcystis wesenbergii) strains were quantified. Growth rates were not impacted by MCPA in any of the fourteen cyanobacterial strains. Glyphosate impacted growth in seven of the fourteen strains, and response differed between strains even within a single species. In general, strains employing a colonial growth strategy were more tolerant to glyphosate in the screening assay. N. spumigena and M. wesenbergii were unaffected by glyphosate at the concentrations used in the functional analysis, and D. lemmermannii had decreased photosynthetic performance from glyphosate. Intermediate concentrations of glyphosate resulted in promotion of PSII functioning in M. aeruginosa, and high concentrations inhibited maximum quantum yield. The lack of significant impacts on M.wesenbergii and N. spumigena, as well as negative effects of PSII functioning in D. lemmermannii, suggest that glyphosate contamination in freshwaters may benefit toxic M. aeruginosa more than competing toxic and non-toxic species or strains.</p>

Effect of Nitrate and Ammonium Ions on the Pigment Content (Xanthophylls, Carotenes and Chlorophylls) of Ramalina Capitata

1995 ◽  
Vol 27 (2) ◽  
pp. 155-160
Author(s):  
M. A. Sanchez-Hoyos ◽  
E. Manrique
Keyword(s):  
Water Supply ◽  
Chlorophyll A ◽  
Nitrate Solution ◽  
Deionized Water ◽  
Pigment Content ◽  
Chlorophyll B ◽  
Ammonium Ions ◽  
Controlled Conditions ◽  
Significant Difference ◽  
Β Carotene

AbstractThalli of Ramalina capitata were sprayed with deionized water, 10 mM solutions of KNO3 or NH4Cl, or maintained without any water supply, for 10 days under controlled conditions. The lichens without a water supply showed an increase n antheraxanthin, lutein and β-carotene. The samples treated with deionized water showed a significant increase in violaxathin, antheraxanthin and β-carotene. The lack of a significant difference in zeaxanthin could indicate the absence of de-epoxidation of violaxanthin to zeaxanthin via antheraxanthin. Those samples treated with nitrate solution showed a significant increase in all pigments except for antheraxanthin. In contrast, ammonium treatment did not induce changes compared to water alone, except that antheraxanthin decreased. The lichens treated with nitrate exhibited a significant increase in both chlorophyll a and chlorophyll b, but ammonium affected only chlorophyll b.

scholarly journals PYRACLOSTROBIN PRESERVES PHOTOSYNTHESIS IN ARABICA COFFEE PLANTS SUBJECTED TO WATER DEFICIT

2020 ◽  
Vol 28 ◽  
pp. 109-119
Author(s):  
Anelisa Figueiredo Peloso ◽  
Sandro Dan Tatagiba ◽  
Francisco José Teixeira Amaral ◽  
Paulo César Cavatte ◽  
José Eduardo Macedo Pezzopane
Keyword(s):  
Quantum Yield ◽  
Water Deficit ◽  
Chlorophyll A ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Photosynthetic Performance ◽  
Effective Quantum Yield ◽  
Fluorescence Maximum ◽  
Common Strategy ◽  
Coffee Plants

The objective of this study was to investigate the effect of pyraclostrobin on the photosynthetic performance of rabica coffee plants subjected or not to a water deficit, using the parameter of gas exchange (net CO2 assimilation, stomatal conductance, transpiration rate, and internal CO2 concentration and nocturnal respiration), chlorophyll fluorescence a parameters (minimum fluorescence, maximum fluorescence, maximum quantum yield of photosystem II, effective quantum yield of PSII, quantum yield of regulated energy dissipation and quantum yield dissipation non-regulated) as well as the concentrations of chloroplast pigments. In the plants maintained without water deficit, pyraclostrobin did not cause any alteration on the parameters of chlorophyll a fluorescence; however, it contributed to an increase in the level of chlorophyll a + b, CO2 assimilation and CO2 influx for the carboxylation sites of the stroma. Decreases in nocturnal respiration in plants treated with pyraclostrobin, submitted or not to water deficit seems to be a common strategy in reducing energy waste in the maintenance metabolism. Under water deficit, pyraclostrobin contributed to increase the photochemical yield, enabling plants to effectively prevent the capture, use and dissipation of light energy.

scholarly journals Physiological Responses of Pocillopora acuta and Porites lutea Under Plastic and Fishing Net Stress

2021 ◽  
Vol 8 ◽  
Author(s):  
Long Ying ◽  
Sutinee Sinutok ◽  
Pathompong Pramneechote ◽  
Pattara Aiyarak ◽  
Peter J. Ralph ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Photochemical Efficiency ◽  
Pigment Content ◽  
Marine Debris ◽  
Maximum Quantum Yield ◽  
Calcification Rate ◽  
Porites Lutea ◽  
Plastic Bag ◽  
Opaque Plastic ◽  
Quantum Yield Of Psii

Marine debris has become a global problem affecting coral health around the globe. However, the photophysiological responses of corals to marine debris stress remain unclear. Therefore, this study firstly investigated transparent and opaque plastic bag shading and fishing nets directly contacting the coral. Photosynthetic performance, pigment content, symbiont density, and calcification rate of a branching coral Pocillopora acuta and a massive coral Porites lutea were investigated after 4 weeks of exposure to marine debris. The results show that the maximum quantum yield of PSII significantly decreased in P. lutea with all treatments, while P. acuta showed no effect on the maximum quantum yield of PSII from any treatments. Transparent plastic bag shading does not affect P. acuta, but significantly affected the maximum photochemical efficiency of P. lutea. Photoacclimation of cellular pigment content was also observed under opaque plastic bag shading for both species at week 2. Fishing nets had the strongest effect and resulted in P. acuta bleaching and P. lutea partial mortality as well as a decline in zooxanthellae density. Calcification rate of P. acuta significantly decreased with treatments using opaque plastic bag and fishing net, but for P. lutea only the treatment with fishing net gave any observable effects. This study suggests that the sensitivities of corals to marine debris differ strongly by species and morphology of the coral.

scholarly journals Relationship between the maximum quantum yield of carbon fixation and the minimum quantum yield of chlorophyll a in vivo fluorescence in the Gulf of St. Lawrence

1995 ◽  
Vol 40 (5) ◽  
pp. 956-968 ◽  
Author(s):  
Marcel Babin ◽  
Jean-Claude Therriault ◽  
Louis Legendre ◽  
Barbara Nieke ◽  
Rainer Reuter ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Chlorophyll A ◽  
Carbon Fixation ◽  
Maximum Quantum Yield ◽  
In Vivo Fluorescence

scholarly journals Anatomy, chlorophyll content and photosynthetic performance in current-year and previous-year Aleppo pine (Pinus halepensis Mill.) needles

2020 ◽  
Vol 44 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Tomo Trstenjak ◽  
Antunovic Dunic ◽  
Selma Mlinaric ◽  
Lidija Begovic ◽  
Marin Skoro ◽  
...  
Keyword(s):  
Chlorophyll Content ◽  
Chlorophyll A ◽  
Pinus Halepensis ◽  
Woody Species ◽  
Photosynthetic Performance ◽  
Aleppo Pine ◽  
Resin Duct ◽  
Chlorophylls A And B ◽  
Crown Defoliation ◽  
Significant Difference

Aleppo pine (Pinus halepensis) is a widespread Mediterranean woody species. Needles usually fall off the tree after the second year, which can be the reason for substantial crown defoliation under extreme environmental stress. The aim of the present investigation was to compare the anatomy, chlorophyll content and photosynthetic performance in current-year (CY) and previous-year (PY) Aleppo pine needles. Chlorophyll concentrations were determined spectrophotometrically, while photosynthetic performance was determined by measuring the increase in chlorophyll a fluorescence (the JIP test). The obtained results revealed that concentrations of chlorophylls a and b were almost twice as great in PY needles as in CY ones. The chlorophyll a to b ratio and values of the maximum quantum yield of photosystem II (Fv/Fm) showed no statistically significant difference between CY and PY needles. However, the performance index (PIABS) was significantly higher in CY needles compared to PY ones. Analysis of PIABS components revealed that CY needles had increased electron transport beyond the primary electron acceptor, QA -, which was associated with a lower value of variable fluorescence at 2 ms (VJ) in comparison with PY needles. Also, some differences were observed in needle anatomy. Current-year needles had an increased proportion of mesophyll tissue, together with decreased proportions of vascular cylinder and resin duct areas. Also, many more starch grains were present in PY than in CY needles. Based on the presented results, it can be concluded that despite considerably lower chlorophyll content, CY needles exhibited photosynthetic performance better than that of older needles, which is an unusual phenomenon in woody species.

Etude sur la teneur en pigment de frênes qui croissent dans des conditions différentes

1973 ◽  
Vol 37 ◽  
Author(s):  
N. Lust
Keyword(s):  
Chlorophyll A ◽  
Strong Influence ◽  
The Other ◽  
Pigment Content ◽  
Chlorophyll B ◽  
Light Quantity ◽  
Yellow Pigments ◽  
The One ◽  
Green Pigments

Pigment content of ashes grown up under different circumstances - The pigment content (chlorophyll a, chlorophyll b,  xanthophyll and carotene) has been researched with ashes grown up under  different light circumstances and varying in age and height.     The results prove that the general laws concerning the influence of light  on the pigment content, don’t always work.     The phenomen is very complex. The light quantity is very important in some  cases, but insignificant in others. It seems origin and height of plants have  a strong influence. The results prove also the influence of the environment  is much higher on small plants as on big ones.     The research indicates finally the correlation between the green pigments,  the yellow pigments, and between the green pigments on the one side and the  yellow ones on the other side.

scholarly journals Performance of a Handheld Chlorophyll-a Fluorometer: Potential Use for Rapid Algae Monitoring

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1409
Author(s):  
Hamdhani Hamdhani ◽  
Drew E. Eppehimer ◽  
David Walker ◽  
Michael T. Bogan
Keyword(s):  
Chlorophyll A ◽  
Surface Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Water Quality Monitoring ◽  
Ambient Light ◽  
Calibration Equation ◽  
Field Samples ◽  
Potential Use

Chlorophyll-a measurements are an important factor in the water quality monitoring of surface waters, especially for determining the trophic status and ecosystem management. However, a collection of field samples for extractive analysis in a laboratory may not fully represent the field conditions. Handheld fluorometers that can measure chlorophyll-a in situ are available, but their performance in waters with a variety of potential light-interfering substances has not yet been tested. We tested a handheld fluorometer for sensitivity to ambient light and turbidity and compared these findings with EPA Method 445.0 using water samples obtained from two urban lakes in Tucson, Arizona, USA. Our results suggested that the probe was not sensitive to ambient light and performed well at low chlorophyll-a concentrations (<25 µg/L) across a range of turbidity levels (50–70 NTU). However, the performance was lower when the chlorophyll-a concentrations were >25 µg/L and turbidity levels were <50 NTU. To account for this discrepancy, we developed a calibration equation to use for this handheld fluorometer when field monitoring for potential harmful algal blooms in water bodies.

scholarly journals Phytotoxicity of Silver Nanoparticles on Tobacco Plants: Evaluation of Coating Effects on Photosynthetic Performance and Chloroplast Ultrastructure

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 744
Author(s):  
Petra Peharec Štefanić ◽  
Karla Košpić ◽  
Daniel Mark Lyons ◽  
Lara Jurković ◽  
Biljana Balen ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Cetyltrimethylammonium Bromide ◽  
Photosynthetic Apparatus ◽  
Chloroplast Ultrastructure ◽  
Photosynthetic Performance ◽  
Pigment Content ◽  
Inhibitory Effects ◽  
Tobacco Plants ◽  
Agriculture And Food ◽  
The Impact

Silver nanoparticles (AgNPs) are the most exploited nanomaterial in agriculture and food production, and their release into the environment raises concern about their impact on plants. Since AgNPs are prone to biotransformation, various surface coatings are used to enhance their stability, which may modulate AgNP-imposed toxic effects. In this study, the impact of AgNPs stabilized with different coatings (citrate, polyvinylpyrrolidone (PVP), and cetyltrimethylammonium bromide (CTAB)) and AgNO3 on photosynthesis of tobacco plants as well as AgNP stability in exposure medium have been investigated. Obtained results revealed that AgNP-citrate induced the least effects on chlorophyll a fluorescence parameters and pigment content, which could be ascribed to their fast agglomeration in the exposure medium and consequently weak uptake. The impact of AgNP-PVP and AgNP-CTAB was more severe, inducing a deterioration of photosynthetic activity along with reduced pigment content and alterations in chloroplast ultrastructure, which could be correlated to their higher stability, elevated Ag accumulation, and surface charge. In conclusion, intrinsic properties of AgNP coatings affect their stability and bioavailability in the biological medium, thereby indirectly contributing changes in the photosynthetic apparatus. Moreover, AgNP treatments exhibited more severe inhibitory effects compared to AgNO3, which indicates that the impact on photosynthesis is dependent on the form of Ag.

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