scholarly journals Attenuation of ultraviolet radiation and photosynthetically active radiation in six Yunnan Plateau lakes of China based on seasonal field investigations

2020 ◽  
Author(s):  
Weilu Wang ◽  
Xuan Yang ◽  
Licheng Huang ◽  
Jiang Qin ◽  
Qichao Zhou
Keyword(s):  
Ultraviolet Radiation ◽  
Photosynthetically Active Radiation ◽  
Trophic State ◽  
Solar Spectrum ◽  
Lake Dianchi ◽  
Factors Affecting ◽  
Active Radiation ◽  
Yunnan Plateau ◽  
Field Investigations ◽  
Lake Fuxian

Solar radiation is a primary driver affecting several physical, chemical and biological processes in lake ecosystems. The attenuation of sunlight in water is directly controlled by optically active substances. Here, the seasonal and interlake heterogeneities of the diffuse attenuation coefficients (Kd(λ)) of ultraviolet radiation (UVR) and photosynthetically active radiation (PAR) were studied based on field investigations in six Yunnan Plateau lakes (i.e., Chenghai, Dianchi, Erhai, Fuxian, Lugu and Yangzong) of China, October 2014‒July 2016. The results revealed that Kd(λ) generally increased with decreasing wavelength and increasing trophic state and that Kd(UVR) presented higher interlake heterogeneity than Kd(PAR). The interlake heterogeneity surpassed the seasonal heterogeneity of Kd(λ), whereas the intralake seasonal heterogeneity, which is related to the lake trophic state and solar spectrum, was obvious. Although the main factors affecting Kd(λ) were chromophoric dissolved organic matter (CDOM) and phytoplankton in general, the interlake heterogeneity was found. In eutrophic, turbid shallow Lake Dianchi, CDOM primarily affected UV-B, whereas total suspended solids (TSS) and/or phytoplankton had important effects on Kd(UV-B), Kd(UV-A) and Kd(PAR). CDOM, TSS and phytoplankton influenced the Kd(UV-B), Kd(UV-A) and Kd(PAR) in the deep mesotrophic Lake Chenghai and Lake Erhai, but the main particulate factors were different between these two lakes. In the deep, oligotrophic clear Lake Fuxian and Lake Lugu, only the significant effect of CDOM on Kd(UVR) in Lake Fuxian was detected. Additionally, the factors affecting Kd(λ) in Lake Yangzong were atypical, possibly due to the artificial addition of massive amounts of ferric chloride.

scholarly journals Cumulative Effects of Ultraviolet Radiation and Photosyntheically Active Radiation on Phycobiliproteins of A Hot-Spring Cyanobacatrium Nostoc sp. strain HKAR-2

2016 ◽  
Vol 4 (3) ◽  
pp. 247-253
Author(s):  
Vinod K. Kannaujiya ◽  
Akhlaqur Rahman ◽  
. Adinath ◽  
Arun S. Sonker ◽  
Jainendra Pathak ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Environmental Conditions ◽  
Photosynthetically Active Radiation ◽  
Biomedical Applications ◽  
Hot Spring ◽  
Ultraviolet B ◽  
Cumulative Effects ◽  
Key Factors ◽  
Active Radiation ◽  
Continuous Induction

Cyanobacteria are cosmopolitan in distribution and have adapted to diverse habitats. Adaptation of cyanobacteria is one of the key factors to withstand harsh environmental conditions. We have investigated the effects of photosynthetically active radiation (PAR; 400–700 nm), ultraviolet-B (UV-B; 280–315 nm) radiation and PAR+UV-B radiations on phycobiliproteins (PBPs) of a hot-spring cyanobacterium Nostoc sp. HKAR-2. There was a continuous induction of both phycoerythrin (PE) and phycocyanin (PC) after exposure of PAR up to 300 min. However, there was an induction in the synthesis of both PE and PC up to 240 min exposure of UV-B and PAR+UV-B radiations. Further exposure showed decline in the synthesis due to rapid uncoupling, bleaching and degradation of PBPs. Similarly, emission fluorescence also showed an induction with a shift towards longer wavelengths after 240 min of UV-B and PAR+UV-B exposure. These results indicate that short duration of UV radiation may promote the synthesis of PBPs that can be utilized in various biotechnological and biomedical applications. Int J Appl Sci Biotechnol, Vol 4(3): 247-253

scholarly journals Remote Sensing of Grassland Biophysical Parameters in the Context of the Sentinel-2 Satellite Mission

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Karolina Sakowska ◽  
Radoslaw Juszczak ◽  
Damiano Gianelle
Keyword(s):  
Photosynthetically Active Radiation ◽  
Solar Spectrum ◽  
Added Value ◽  
Estimation Accuracy ◽  
Least Squares Regression ◽  
Satellite Mission ◽  
Biophysical Parameters ◽  
Active Radiation ◽  
Reflectance Data ◽  
Sentinel 2

This study investigates the potential of the Sentinel-2 satellite for monitoring the seasonal changes in grassland total canopy chlorophyll content (CCC), fraction of photosynthetically active radiation absorbed by the vegetation canopy (FAPAR), and fraction of photosynthetically active radiation absorbed only by its photosynthesizing components (GFAPAR). Reflectance observations were collected on a continuous basis during growing seasons by means of a newly developed ASD-WhiteRef system. Two models using Sentinel-2 simulated data (linear regression-vegetation indices (VIs) approach and multiple regression (MR) reflectance approach) were tested to estimate vegetation biophysical parameters. To assess whether the use of full solar spectrum reflectance data is able to provide an added value in CCC and GFAPAR estimation accuracy, a third model based on partial least squares regression (PLSR) and the ASD-WhiteRef reflectance data was tested. The results showed that FAPAR remained quite stable during the reproduction and senescence stages, and no significant relationships between FAPAR and VIs were found. On the other hand, GFAPAR showed clearer seasonal trends. The comparison of the three models revealed no significant differences in the accuracies of CCC and GFAPAR predictions and demonstrated a strong contribution of SWIR bands to the explained variability of investigated parameters. The promising results highlight the potential of the Sentinel-2 satellite for retrieving biophysical parameters from space.

Effects of Natural Radiation, Photosynthetically Active Radiation and Artificial Ultraviolet Radiation-B on the Chloroplast Organization and Metabolism ofPorphyra acanthophoravar.brasiliensis(Rhodophyta, Bangiales)

2012 ◽  
Vol 18 (6) ◽  
pp. 1467-1479 ◽  
Author(s):  
Zenilda L. Bouzon ◽  
Fungyi Chow ◽  
Carmen S. Zitta ◽  
Rodrigo W. dos Santos ◽  
Luciane C. Ouriques ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Photosynthetically Active Radiation ◽  
Laser Scanning ◽  
Reductase Activity ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ambient Conditions ◽  
Natural Radiation ◽  
Active Radiation ◽  
Ultraviolet Radiation B

AbstractWe undertook a study ofPorphyra acanthophoravar.brasiliensisto determine its responses under ambient conditions, photosynthetically active radiation (PAR), and PAR+UVBR (ultraviolet radiation-B) treatment, focusing on changes in ultrastructure, and cytochemistry. Accordingly, control ambient samples were collected in the field, and two different treatments were performed in the laboratory. Plants were exposed to PAR at 60 μmol photons m−2s−1and PAR + UVBR at 0.35 W m−2for 3 h per day during 21 days ofin vitrocultivation. Confocal laser scanning microscopy analysis of the vegetative cells showed single stellate chloroplast in ambient and PAR samples, but in PAR+UVBR-exposed plants, the chloroplast showed alterations in the number and form of arms. Under PAR+UVBR treatment, the thylakoids of the chloroplasts were disrupted, and an increase in the number of plastoglobuli was observed, in addition to mitochondria, which appeared with irregular, disrupted morphology compared to ambient and PAR samples. After UVBR exposure, the formation of carpospores was also observed. Plants under ambient conditions, as well as those treated with PAR and PAR+UVBR, all showed different concentrations of enzymatic response, including glutathione peroxidase and reductase activity. In summary, the present study demonstrates thatP. acanthophoravar.brasiliensisshows the activation of distinct mechanisms against natural radiation, PAR and PAR+UVBR.

The net effect of ultraviolet radiation on atmospheric dimethylsulphide over the Southern Indian Ocean

2005 ◽  
Vol 363 (1826) ◽  
pp. 187-189 ◽  
Author(s):  
Dominic R. Kniveton ◽  
Martin C. Todd ◽  
Jean Sciare ◽  
Nikos Mihalopoulos
Keyword(s):  
Wind Speed ◽  
Indian Ocean ◽  
Ultraviolet Radiation ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Photosynthetically Active Radiation ◽  
Inverse Relationship ◽  
Sea Surface ◽  
Southern Indian Ocean ◽  
Active Radiation

Dimethylsulphide (DMS) in the atmosphere may play an important role in the climate system. This study shows an inverse relationship between ultraviolet extremes and atmospheric DMS, independent of changes in wind speed, sea–surface temperature and photosynthetically active radiation, as measured at Amsterdam Island in the Southern Indian Ocean.

scholarly journals Transmission of ultraviolet, visible and near-infrared solar radiation to plants within a seasonal snow pack

2019 ◽  
Vol 18 (8) ◽  
pp. 1963-1971 ◽  
Author(s):  
T. Matthew Robson ◽  
Pedro J. Aphalo
Keyword(s):  
Solar Radiation ◽  
Ultraviolet Radiation ◽  
Photosynthetically Active Radiation ◽  
Near Infrared ◽  
Snow Pack ◽  
Active Radiation ◽  
Seasonal Snow ◽  
Better Than

Ultraviolet radiation is transmitted better than longer wavelengths through the upper centimetres of a seasonal snowpack, where about 10% of the incident photosynthetically active radiation reaches 7 cm depth.

Sign in / Sign up

Export Citation Format

Share Document