Influence of the Microbiological Processes in Soil on Vertical Migration of Radionuclides

1997 ◽  
pp. 71-80
Author(s):  
Yu. I. Bondar ◽  
A. G. Galeeva ◽  
L. V. Gerasimova ◽  
I. B. Tchernetsova
Keyword(s):  
Vertical Migration ◽  
Microbiological Processes

scholarly journals Response of Vertical Migration and Leaching of Nitrogen in Percolation Water of Paddy Fields under Water-Saving Irrigation and Straw Return Conditions

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 868 ◽  
Author(s):  
Chengxin Zheng ◽  
Zhanyu Zhang ◽  
Yunyu Wu ◽  
Richwell Mwiya
Keyword(s):  
Vertical Migration ◽  
Growth Stage ◽  
Nitrogen Leaching ◽  
Water Saving ◽  
Paddy Fields ◽  
N Leaching ◽  
Leaching Losses ◽  
Leaching Loss ◽  
Straw Return ◽  
Percolation Water

The use of water-saving irrigation techniques has been encouraged in rice fields in response to irrigation water scarcity. Straw return is an important means of straw reuse. However, the environmental impact of this technology, e.g., nitrogen leaching loss, must be further explored. A two-year (2017–2018) experiment was conducted to investigate the vertical migration and leaching of nitrogen in paddy fields under water-saving and straw return conditions. Treatments included traditional flood irrigation (FI) and two water-saving irrigation regimes: rain-catching and controlled irrigation (RC-CI) and drought planting with straw mulching (DP-SM). RC-CI and DP-SM both significantly decreased the irrigation input compared with FI. RC-CI increased the rice yield by 8.23%~12.26%, while DP-SM decreased it by 8.98%~15.24% compared with FI. NH4+-N was the main form of the nitrogen leaching loss in percolation water, occupying 49.06%~50.97% of TN leaching losses. The NH4+-N and TN concentration showed a decreasing trend from top to bottom in soil water of 0~54 cm depth, while the concentration of NO3−-N presented the opposite behavior. The TN and NH4+-N concentrations in percolation water of RC-CI during most of the rice growth stage were the highest among treatments in both years, and DP-SM showed a trend of decreasing TN and NH4+-N concentrations. The NO3−-N concentrations in percolation water showed a regular pattern of DP-SM > RC-CI > FI during most of the rice growth stage. RC-CI and DP-SM remarkably reduced the amount of N leaching losses compared to FI as a result of the significant decrease of percolation water volumes. The tillering and jointing-booting stages were the two critical periods of N leaching (accounted for 74.85%~86.26% of N leaching losses). Great promotion potential of RC-CI and DP-SM exists in the lower reaches of the Yangtze River, China, and DP-SM needs to be further optimized.

Diel, lunar and seasonal vertical migration in the deep western Gulf of Mexico evidenced from a long-term data series of acoustic backscatter

2021 ◽  
pp. 102562
Author(s):  
Laura Ursella ◽  
Sara Pensieri ◽  
Enric Pallàs-Sanz ◽  
Sharon Z. Herzka ◽  
Roberto Bozzano ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Vertical Migration ◽  
Acoustic Backscatter ◽  
Data Series ◽  
Term Data

Diel vertical migration of mesozooplankton in the northern Yellow Sea

2021 ◽  
Author(s):  
Ruping Ge ◽  
Hongju Chen ◽  
Guangxing Liu ◽  
Yanzhong Zhu ◽  
Qiang Jiang
Keyword(s):  
Vertical Migration ◽  
Yellow Sea ◽  
Diel Vertical Migration ◽  
Northern Yellow Sea

scholarly journals Role of large-scale advection and small-scale turbulence on vertical migration of gyrotactic swimmers

2019 ◽  
Vol 4 (12) ◽  
Author(s):  
C. Marchioli ◽  
H. Bhatia ◽  
G. Sardina ◽  
L. Brandt ◽  
A. Soldati
Keyword(s):  
Vertical Migration ◽  
Large Scale ◽  
Small Scale ◽  
Scale Turbulence

scholarly journals Assess the Effectiveness of protective Concrete coatings of microbiological sulfuric acid Aggression

2019 ◽  
Vol 97 ◽  
pp. 02022
Author(s):  
Viktor Sopov ◽  
Julia Danchenko ◽  
Ekaterina Latorez
Keyword(s):  
Sulfuric Acid ◽  
Building Structures ◽  
Predominant Role ◽  
Microbiological Processes ◽  
Repair Materials ◽  
Bactericidal Properties ◽  
Mineral Acids ◽  
Concrete Building ◽  
Modified Epoxy

Specification of corrosion processes in sewerage networks, the predominant role of microbiological processes in them requires the protection of concrete with materials resistant to specific biogenic sulfuric acid aggression. The effective protective materials, in this case, are those that, in addition to acid-proofing materials, have bactericidal properties. Polymer composite materials (PCM) of cold curing based on modified epoxy-resin, resins with dispersed oxides as fillers are widely used in construction. Unique properties and simple technologies make it possible to use them as injection formulations for repair, restoration and restoration of building structures and structures, waterproofing and facing materials, for impregnating, gluing and coating metal, wooden, brick and concrete building structures and parts. In the reconstruction and restoration of sewerage collectors operating under conditions of exposure to liquid biochemically aggressive media with mineral acids and organic substances, particular attention is paid to the permeability of repair materials. Based on the results of the study, PCM compositions were chosen whose estimated lifetime is about 20 years, ensuring reliable protection of the sewage collectors from corrosion.

A laboratory study of vertical migration

1955 ◽  
Vol 144 (916) ◽  
pp. 329-354 ◽  
Keyword(s):  
Light Intensity ◽  
Vertical Migration ◽  
Time Course ◽  
Tap Water ◽  
Low Light ◽  
Overhead Light ◽  
Light Intensities ◽  
Orientation Response ◽  
Reduced Light ◽  
Characteristic Maximum

In a tank filled with a suspension of indian ink in tap water, a population of Daphnia magna will undergo a complete cycle of vertical migration when an overhead light source is cycli­cally varied in intensity. A ‘dawn rise’ to the surface at low intensity is followed by the descent of the animals to a characteristic maximum depth. The animals rise to the surface again as the light decreases, and finally show a typical midnight sinking. The light intensities at the level of the animals in this experiment are of the same order as those which have been reported in field observations; the time course of the movement also repeats the natural conditions in the field. The process is independent of the duration of the cycle and is related only to the variation in overhead light intensity. At low light intensity the movement of the animal is determined solely by positive photo-kinesis; the dawn rise is a manifestation of this, and is independent of the direction of the light. At high light intensities there is an orientation response which is superimposed upon an alternating positive (photokinetic) phase and a negative phase during which movement is inhibited. The fully oriented animal shows a special type of positive and negative phototaxis, moving towards the light at reduced light intensities and away from it when the light intensity is increased. In this condition it follows a zone of optimum light intensity with some exactness. Experiments show that an animal in this fully oriented condition will respond to the slow changes of intensity characteristic of the diurnal cycle, while being little affected by tran­sient changes of considerable magnitude.

scholarly journals Comparison of zooplankton vertical migration in an ice-free and a seasonally ice-covered Arctic fjord: An insight into the influence of sea ice cover on zooplankton behavior

2010 ◽  
Vol 55 (2) ◽  
pp. 831-845 ◽  
Author(s):  
Margaret I. Wallace ◽  
Finlo R. Cottier ◽  
Jørgen Berge ◽  
Geraint A. Tarling ◽  
Colin Griffiths ◽  
...  
Keyword(s):  
Sea Ice ◽  
Vertical Migration ◽  
Ice Cover ◽  
Arctic Fjord ◽  
Insight Into
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