scholarly journals Copper-, Lead- and Mercury-Induced Changes in Maximum Quantum Yield, Chlorophyll A Content and Relative Growth of Three Malaysian Green Macroalgae

2013 ◽  
Vol 9 (1) ◽  
Author(s):  
Hazlina Ahamad Zakeri ◽  
Luqman Abu Bakar
Keyword(s):  
Quantum Yield ◽  
Algal Species ◽  
Maximum Quantum Yield ◽  
Green Macroalgae ◽  
Relative Growth ◽  
Chl A ◽  
Caulerpa Lentillifera ◽  
Induced Changes ◽  
Chlorophyll A Content ◽  
Positive Effect

In this study, we reported on the responses of three Malaysian green algae, Caulerpa racemosa, Caulerpa lentillifera and Ulva reticulata against three heavy metals, copper (Cu), lead (Pb) and mercury (Hg). Responses were determined as maximum quantum yield (Fv/Fm) for photosynthetic quantum efficiency, chlorophyll (chl) a content and relative growth measured as changes in fresh weight. The algae were exposed for 8h in two concentrations of metals, which were 1 mg/L and 2 mg/L. In general, all algae were severely affected by the presence of Hg compared to the other two metals. Fv/Fm of the algae was significantly reduced to the lowest of 18% in 1 mg/L Hg as observed in C. racemosa while the lowest for Cu and Pb was 29% and 41%, respectively, also observed in similar algal species. All algae showed an undetected value of Fv/Fm when concentration of Hg was increased to 2 mg/L. An increase in Fv/Fm was observed for C. lentillifera in 1 mg/L of Cu and Pb but the value showed a reduction when the concentration of both metals was increased to 2 mg/L. Among the algae, Fv/Fm of C. racemosa was severely affected by the presence of all metals particularly at 2 mg/L where it showed undetected value. An increase in the content of chl a was observed in C. racemosa and C. lentillifera for each metals at both concentrations while a decrease in the content was observed in U. reticulata. Algal relative growth was negatively affected by the presence of metals with Hg showed the strongest effect. However, some algae showed a positive effect of Pb on their growth.

scholarly journals Inhibitory effects of extracts from Cinnamomum camphora fallen leaves on algae

2018 ◽  
Vol 77 (11) ◽  
pp. 2545-2554 ◽  
Author(s):  
Zumulati Yakefu ◽  
Wulan Huannixi ◽  
Chaolin Ye ◽  
Tiefeng Zheng ◽  
Silan Chen ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Cinnamomum Camphora ◽  
Maximum Quantum Yield ◽  
Inhibitory Effects ◽  
Chl A ◽  
Water Extracts ◽  
Methanol Extracts ◽  
Potential Value ◽  
Photosystem Ii Photochemistry ◽  
Fallen Leaves

Abstract Natural allelochemicals are considered as a source of algaecides. To uncover the anti-algal activity of Cinnamomum camphora fallen leaves and promote their usage as algaecides, the composition of their water and methanol extracts was analyzed, and the inhibitory effects of extracts on the growth of Microcystis aeruginosa and Chlamydomonas reinhardtii, and chlorophyll (Chl) content and photosynthetic abilities in C. reinhardtii were investigated. Twenty-five compounds were detected in the water extracts, mainly including terpenoids, esters, alcohols, and ketones. Compared to water extracts, there were more compounds and higher concentration in methanol extracts. Both water and methanol extracts inhibited the growth of the two algae, and 15 mg·ml−1 methanol extracts killed the algal cells after 48 h. The levels of Chl a and Chl b, as well as maximum quantum yield of photosystem II photochemistry (Fv/Fm) in C. reinhardtii cells reduced gradually with increasing the concentration of extracts, while the maximum quantum yield of non-photochemical de-excitation (φDO) increased gradually. At the same concentration, methanol extracts showed stronger inhibitory effects than water extracts, due to their higher number of compounds and higher concentration. Therefore, C. camphora fallen leaves have a potential value as an algaecide.

scholarly journals Nutrient Loading, Temperature and Heat Wave Effects on Nutrients, Oxygen and Metabolism in Shallow Lake Mesocosms Pre-Adapted for 11 Years

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 127
Author(s):  
Erik Jeppesen ◽  
Joachim Audet ◽  
Thomas A. Davidson ◽  
Érika M. Neif ◽  
Yu Cao ◽  
...  
Keyword(s):  
Heat Wave ◽  
Shallow Lake ◽  
Nutrient Loading ◽  
Global Changes ◽  
Significant Positive Effect ◽  
Mixed Effect ◽  
Chl A ◽  
Nutrient Loadings ◽  
Positive Effect ◽  
Oxygen Concentrations

Global changes (e.g., warming and population growth) affect nutrient loadings and temperatures, but global warming also results in more frequent extreme events, such as heat waves. Using data from the world’s longest-running shallow lake experimental mesocosm facility, we studied the effects of different levels of nutrient loadings combined with varying temperatures, which also included a simulated 1-month summer heat wave (HW), on nutrient and oxygen concentrations, gross ecosystem primary production (GPP), ecosystem respiration (ER), net ecosystem production (NEP) and bacterioplankton production (BACPR). The mesocosms had two nutrient levels (high (HN) and low (LN)) combined with three different temperatures according to the IPCC 2007 warming scenarios (unheated, A2 and A2 + 50%) that were applied for 11 years prior to the present experiment. The simulated HW consisted of 5 °C extra temperature increases only in the A2 and A2 + 50% treatments applied from 1 July to 1 August 2014. Linear mixed effect modeling revealed a strong effect of nutrient treatment on the concentration of chlorophyll a (Chl-a), on various forms of phosphorus and nitrogen as well as on oxygen concentration and oxygen percentage (24 h means). Applying the full dataset, we also found a significant positive effect of nutrient loading on GPP, ER, NEP and BACPR, and of temperature on ER and BACPR. The HW had a significant positive effect on GPP and ER. When dividing the data into LN and HN, temperature also had a significant positive effect on Chl-a in LN and on orthophosphate in HN. Linear mixed models revealed differential effects of nutrients, Chl-a and macrophyte abundance (PVI) on the metabolism variables, with PVI being particularly important in the LN mesocosms. All metabolism variables also responded strongly to a cooling-low irradiance event in the middle of the HW, resulting in a severe drop in oxygen concentrations, not least in the HN heated mesocosms. Our results demonstrate strong effects of nutrients as well as an overall rapid response in oxygen metabolism and BACPR to changes in temperature, including HWs, making them sensitive ecosystem indicators of climate warming.

Improvements in Self-Concept Associated with Reductions in Negative Mood in Preadolescents Enrolled in an After-School Physical Activity Program

2005 ◽  
Vol 97 (2) ◽  
pp. 400-404 ◽  
Author(s):  
James J. Annesi
Keyword(s):  
Negative Mood ◽  
Exercise Program ◽  
Self Concept ◽  
After School ◽  
Activity Program ◽  
Cognitive Behavioral Theory ◽  
Exercise Induced ◽  
Induced Changes ◽  
Positive Effect ◽  
School Care

Preadolescents enrolled in either a 3 times per week, 12-week exercise program ( n = 50) or a no-exercise program control condition ( n = 42) during their after-school care, were assessed for indication of whether exercise-induced changes in self-concept and overall negative mood were negatively correlated. Significant improvements in ratings of self-concept and of negative mood were found over 12 wk. Inverse relationships were found between changes in physical self-concept with overall self-concept and negative mood ( r = –.40 and –.36, respectively). Results supported the positive effect of exercise on the assessed psychological factors in preadolescents. Cognitive behavioral theory-based explanations of the findings were discussed.

scholarly journals Selenium supply affects chlorophyll concentration and biomass production of maize (Zea mays L.)

2018 ◽  
Vol 69 (4) ◽  
pp. 249-255
Author(s):  
Aliu Sali ◽  
Dukagjin Zeka ◽  
Shukri Fetahu ◽  
Imer Rusinovci ◽  
Hans-Peter Kaul
Keyword(s):  
Biomass Production ◽  
Root Biomass ◽  
Zea Mays L ◽  
Chlorophyll Concentration ◽  
Total Chlorophyll ◽  
Chl A ◽  
Maize Population ◽  
Maize Genotypes ◽  
Positive Effect ◽  
Shoot And Root Biomass

Summary The objective of this work was to investigate the effect of selenium (Se) on the biomass production and the contents of photosynthetically active pigments. The pot experiment included two maize genotypes: hybrid 408BC originating from Croatia and a local maize population from Kosovo. The doses of Se applied were 0, 1.30, 6.57, 13, and 26 mg kg−1. The lowest Se dose (1.30 mg Se kg−1) had a positive effect on shoot and root biomass production as well as on the contents of chlorophyll b (Chl-b), total chlorophyll, and carotenoids (just for the hybrid). Chlorophyll a (Chl-a) was reduced with increasing Se doses, whereas chlorophyll b (Chl-b) and total chlorophyll further increased with medium Se doses. The highest Se dose strongly reduced biomass and the contents of photosynthetically active pigments. Chl-a and carotenoids positively correlated with shoot (for both genotypes) and root (for the hybrid) biomass, whereas no correlation was observed between Chl-b and biomass. Low amounts of Se application are favorable for biomass production and chlorophyll and carotenoids contents, whereas high amounts of Se application negatively affect both.

scholarly journals Potential Maximum Quantum Yield of Photosystem II Reflects the Growth Rate of Chattonella marina in Field Bloom Samples

2016 ◽  
Vol 61 (2) ◽  
pp. 331-335 ◽  
Author(s):  
Xuchun Qiu ◽  
Kouki Mukai ◽  
Yohei Shimasaki ◽  
Michito Tsuyama ◽  
Tadashi Matsubara ◽  
...  
Keyword(s):  
Growth Rate ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Maximum Quantum Yield ◽  
Chattonella Marina ◽  
Potential Maximum

Zinc requirement for two phytoplankton strains of the Tasman Sea

2017 ◽  
Vol 68 (2) ◽  
pp. 361 ◽  
Author(s):  
Marie Sinoir ◽  
Andrew R. Bowie ◽  
Mathieu Mongin ◽  
Edward C. V. Butler ◽  
Christel S. Hassler
Keyword(s):  
Growth Rate ◽  
Quantum Yield ◽  
Maximum Quantum Yield ◽  
Biological Transport ◽  
Short Term ◽  
Pennate Diatom ◽  
Cellular Energy ◽  
Zn Uptake ◽  
Tasman Sea ◽  
Zinc Concentrations

Zinc has been proposed as a limiting, or co-limiting, micronutrient for phytoplankton. In the Tasman Sea, extremely low zinc concentrations have been reported, raising the possibility there of limitation of phytoplankton growth by zinc. The pennate diatom Nitzschia closterium (CS-1) and the coccolithophorid Emiliania huxleyi (CS-812) were cultured in two low zinc concentrations (Zn2+ = 1.5 pmolL–1 and Zn2+ = 1.5 nmolL–1) mimicking conditions found in coastal and pelagic Tasman Sea. To monitor phytoplankton health and productivity, the maximum quantum yield (Fv/Fm), growth rate and cell size were analysed. These parameters showed that both strains were able to adapt and still grow. Short-term uptake experiments revealed an effect on Zn biological transport, with consequences for its bioavailability. When grown at low Zn2+ concentrations, E. huxleyi showed an induction of a two-transporter system, highly dependent on photosynthetic energy for Zn uptake. N. closterium was able to survive without inducing a higher-affinity Zn transporter. Its Zn uptake was also highly dependent on cellular energy and the ability to potentially access labile complexed forms of Zn. This strategy, thus, represented an advantage over E. huxleyi. Results are discussed in the context of the conditions found in the Tasman Sea.

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