Seasonal and spatial variations of microcystins in Poyang Lake, the largest freshwater lake in China

2017 ◽  
Vol 25 (7) ◽  
pp. 6300-6307 ◽  
Author(s):  
Li Zhang ◽  
Jutao Liu ◽  
Dawen Zhang ◽  
Linguang Luo ◽  
Qiegen Liao ◽  
...  
Keyword(s):  
Poyang Lake ◽  
Spatial Variations ◽  
Freshwater Lake ◽  
Seasonal And Spatial Variations

Contribution of large bacteria to bacterial biomass in a deep freshwater lake (Lake Biwa, Japan)

2020 ◽  
Vol 85 ◽  
pp. 131-139
Author(s):  
S Shen ◽  
Y Shimizu
Keyword(s):  
Cell Volume ◽  
Bacterial Cell ◽  
Lake Biwa ◽  
Bacterial Biomass ◽  
Spatial Variations ◽  
Freshwater Lake ◽  
Heterotrophic Nanoflagellates ◽  
Bacterial Productivity ◽  
Transmission Electron ◽  
Seasonal And Spatial Variations

Despite the importance of bacterial cell volume in microbial ecology in aquatic environments, literature regarding the effects of seasonal and spatial variations on bacterial cell volume remains scarce. We used transmission electron microscopy to examine seasonal and spatial variations in bacterial cell size for 18 mo in 2 layers (epilimnion 0.5 m and hypolimnion 60 m) of Lake Biwa, Japan, a large and deep freshwater lake. During the stratified period, we found that the bacterial cell volume in the hypolimnion ranged from 0.017 to 0.12 µm3 (median), whereas that in the epilimnion was less variable (0.016 to 0.033 µm3, median) and much lower than that in the hypolimnion. Additionally, in the hypolimnion, cell volume during the stratified period was greater than that during the mixing period (up to 5.7-fold). These differences in cell volume resulted in comparable bacterial biomass in the hypolimnion and epilimnion, despite the fact that there was lower bacterial abundance in the hypolimnion than in the epilimnion. We also found that the biomass of larger bacteria, which are not likely to be grazed by heterotrophic nanoflagellates, increased in the hypolimnion during the stratified period. Our data suggest that estimation of carbon flux (e.g. bacterial productivity) needs to be interpreted cautiously when cell volume is used as a constant parametric value. In deep freshwater lakes, a difference in cell volume with seasonal and spatial variation may largely affect estimations.

scholarly journals Seasonal and spatial variations in biomarker baseline levels within Arctic populations of mussels (Mytilus spp.)

2019 ◽  
Vol 656 ◽  
pp. 921-936 ◽  
Author(s):  
Ekaterina Storhaug ◽  
Jasmine Nahrgang ◽  
Kristine Bondo Pedersen ◽  
Steven J. Brooks ◽  
Laura Petes ◽  
...  
Keyword(s):  
Spatial Variations ◽  
Seasonal And Spatial Variations ◽  
Baseline Levels

scholarly journals Seasonal and Spatial Variation of Volatile Organic Compounds in Ambient Air of Almaty City, Kazakhstan

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1592
Author(s):  
Olga P. Ibragimova ◽  
Anara Omarova ◽  
Bauyrzhan Bukenov ◽  
Aray Zhakupbekova ◽  
Nassiba Baimatova
Keyword(s):  
Air Pollution ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Power Plants ◽  
Ambient Air ◽  
Spatial Variations ◽  
Primary Sources ◽  
Volatile Organic ◽  
Seasonal And Spatial Variations ◽  
Before And After

Air pollution is one of the primary sources of risk to human health in the world. In this study, seasonal and spatial variations of multiple volatile organic compounds (VOCs) were measured at six sampling sites in Almaty, Kazakhstan. The seasonal and spatial variations of 19 VOCs were evaluated in 2020, including the periods before and after COVID-19 lockdown. The concentrations of 9 out of 19 VOCs had been changed significantly (p < 0.01) during 2020. The maximum concentrations of total VOCs (TVOCs) were observed on 15, 17, and 19 January and ranged from 233 to 420 µg m−3. The spatial distribution of TVOCs concentrations in the air during sampling seasons correlated with the elevation and increased from southern to northern part of Almaty, where Combined Heat and Power Plants are located. The sources of air pollution by VOCs were studied by correlations analysis and BTEX ratios. The ranges of toluene to benzene ratio and benzene, toluene, and ethylbenzene demonstrated two primary sources of BTEX in 2020: traffic emissions and biomass/biofuel/coal burning. Most of m-, p-xylenes to ethylbenzene ratios in this study were lower than 3 in all sampling periods, evidencing the presence of aged air masses at studied sampling sites from remote sources.

Seasonal and spatial variations of enhanced gamma ray dose rates derived from 222Rn progeny during precipitation in Japan

2007 ◽  
Vol 41 (37) ◽  
pp. 8043-8057 ◽  
Author(s):  
Y. Inomata ◽  
M. Chiba ◽  
Y. Igarashi ◽  
M. Aoyama ◽  
K. Hirose
Keyword(s):  
Gamma Ray ◽  
Spatial Variations ◽  
Dose Rates ◽  
Seasonal And Spatial Variations
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