Temperature selections of Anguilla japonica (L.) elvers, and their implications for migration

1991 ◽  
Vol 42 (6) ◽  
pp. 743 ◽  
Author(s):  
YL Chen ◽  
H Chen
Keyword(s):  
Thermal Gradient ◽  
Power Plants ◽  
Anguilla Japonica ◽  
Japanese Eel ◽  
Thermal Gradients ◽  
Temperature Selection ◽  
Naturally Occurring ◽  
Thermal Effluents ◽  
Stainless Steel Heat ◽  
Steel Heat

This study investigated the temperature selections of elvers of the Japanese eel, Anguilla japonica (L.), that had been acclimatized to various temperatures and salinities. The results provide information needed to assess the possible effects of thermal effluents from power plants and of naturally occurring thermal gradients on the freshwater migration and fishery harvest of elvers. A 7.14-m-long plastic pipe (i.d. 11 cm) fitted with two stainless-steel heat-exchange tubes was used for the study. The countercurrent design of the system provided a thermal gradient ranging from 11� C at one end of the pipe to 31� C at the other. Elvers could swim free of obstacles inside the pipe. They were acclimatized to 13, 15, 17, 19 or 21� C before being subjected to the thermal gradient. The distribution of elvers in the pipe was studied during a 24-h period. The results indicate that the temperature to which the elvers gravitated was higher than their acclimatization temperature for acclimatizaion temperatures between 13 and 21�C. The thermal preference of elvers acclimatized to salinities of 10 or 32 did not differ. The temperature- selection pattern of the elvers suggests that thermal effluents from power plants may not adversely affect the immigration of elvers.

scholarly journals Bacterioplankton Metacommunity Processes across Thermal Gradients: Weaker Species Sorting but Stronger Niche Segregation in Summer than in Winter in a Subtropical Bay

2018 ◽  
Vol 85 (2) ◽  
Author(s):  
Lijuan Ren ◽  
Xingyu Song ◽  
Dan He ◽  
Jianjun Wang ◽  
Meiting Tan ◽  
...  
Keyword(s):  
Microbial Ecology ◽  
Nuclear Power ◽  
Power Plants ◽  
Thermal Gradients ◽  
Effluent Water ◽  
Species Sorting ◽  
Marine Bacterioplankton ◽  
Thermal Effluents ◽  
Thermal Effluent ◽  
Surrounding Seawater

ABSTRACT Thermal effluents from nuclear power plants greatly change the environmental and ecological conditions of the receiving marine water body, but knowledge about their impact on microbial ecology is limited. Here we used high-throughput sequencing of the 16S rRNA gene to examine marine bacterioplankton metacommunity assembly across thermal gradients in two representative seasons (i.e., winter and summer) in a subtropical bay located on the northern coast of the South China Sea. We found high heterogeneity in bacterioplankton community compositions (BCCs) across thermal gradients and between seasons. The spatially structured temperature gradient created by thermal effluents was the key determinant of BCCs, but its influence differed by season. Using a metacommunity approach, we found that in the thermal discharge area, i.e., where water is frequently exchanged with surrounding seawater and thermal effluent water, the BCC spatial patterns were shaped by species sorting rather than by mass effects from surrounding seawater or by dilution of thermal effluent water by surrounding seawater. However, this effect of species sorting was weaker in summer than in winter seawater. In both seasons, the bacterioplankton community structure was predominately determined by niche sharing; however, the relative importance of niche segregation was enhanced in summer seawater. Our findings suggest that for the seasonal differences in metacommunity processes, the BCCs of subtropical summer seawater were more sensitive to temperature and were more difficult to predict than those of winter seawater in the face of different intensities of thermal impacts. IMPORTANCE Understanding the mechanisms of bacterial community assembly across environmental gradients is one of the major goals of marine microbial ecology. Thermal effluents from two nuclear power plants have been present in the subtropical Daya Bay for more than 20 years and have generated a comparatively stable and long thermal gradient (a temperature increase from 0 to 10°C). The environmental patches across thermal gradients are heterogeneous and very strongly interconnected on a microbial scale; thus, this is a useful model for the study of the metacommunity processes (i.e., patch dynamics, species sorting, mass effects, and neutral processes) that underlie marine bacterioplankton assembly. The significance of our research is to reveal how environmental conditions and dispersal-related processes interact to influence bacterioplankton metacommunity processes and their seasonal differences across thermal gradients. Our results may advance the understanding of marine microbial ecology under future conditions of global warming.

Fission Gas Bubbles in Fractured UO2

1968 ◽  
Vol 26 ◽  
pp. 286-287
Author(s):  
O. M. Katz
Keyword(s):  
Electron Microscopy ◽  
Thermal Gradient ◽  
Gas Bubbles ◽  
Inert Gas ◽  
Thermal Gradients ◽  
Fission Gas ◽  
Beam Heating ◽  
Limited Application ◽  
Bubble Characteristics ◽  
Electron Beam Heating

The swelling of irradiated UO2 has been attributed to the migration and agglomeration of fission gas bubbles in a thermal gradient. High temperatures and thermal gradients obtained by electron beam heating simulate reactor behavior and lead to the postulation of swelling mechanisms. Although electron microscopy studies have been reported on UO2, two experimental procedures have limited application of the results: irradiation was achieved either with a stream of inert gas ions without fission or at depletions less than 2 x 1020 fissions/cm3 (∼3/4 at % burnup). This study was not limited either of these conditions and reports on the bubble characteristics observed by transmission and fractographic electron microscopy in high density (96% theoretical) UO2 irradiated between 3.5 and 31.3 x 1020 fissions/cm3 at temperatures below l600°F. Preliminary results from replicas of the as-polished and etched surfaces of these samples were published.

Analysis of a Stainless Steel Heat Pipe based on Operation Limits

2014 ◽  
Vol 8 (3) ◽  
pp. 599 ◽  
Author(s):  
Paulo Henrique Dias dos Santos ◽  
Larissa Krambeck ◽  
Diogo Luiz Figueiredo dos Santos ◽  
Thiago Antonini Alves
Keyword(s):  
Stainless Steel ◽  
Heat Pipe ◽  
Stainless Steel Heat ◽  
Steel Heat

Isolation of two types of cDNA encoding growth hormone receptor-like genes in the Japanese eel, Anguilla japonica

2002 ◽  
Vol 68 (sup1) ◽  
pp. 959-960 ◽  
Author(s):  
YUICHI OZAKI ◽  
HARUHISA FUKADA ◽  
YUKINORI KAZETO ◽  
SHINJI ADACHI ◽  
AKIHIKO HARA ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Hormone Receptor ◽  
Growth Hormone Receptor ◽  
Anguilla Japonica ◽  
Japanese Eel

Correlation Between PTEN and VEGF Expressions During the Development of Gas Gland in Japanese Eel (Anguilla japonica) Stimulated by Exogenous Hypophyseal Factors

2010 ◽  
Vol 1 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Yi-Fan Chen ◽  
Shan-Ru Jeng ◽  
Ming-Chyuan Chen ◽  
Jin-Chywan Gwo ◽  
Yung-Sen Huang
Keyword(s):  
Anguilla Japonica ◽  
Japanese Eel ◽  
Gas Gland

Toward living nanomachines

2018 ◽  
Author(s):  
Christof Mast ◽  
Friederike Möller ◽  
Moritz Kreysing ◽  
Severin Schink ◽  
Benedikt Obermayer ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Thermal Gradient ◽  
Molecular Level ◽  
Minimal System ◽  
Thermal Gradients ◽  
Temperature Oscillations ◽  
Fluid Convection ◽  
Inanimate Matter ◽  
High Concentrations ◽  
Periodic Temperature

How does inanimate matter become transformed into animate matter? Living systems evolve by replication and selection at the molecular level and this chapter considers how to establish a synthetic, minimal system that can support molecular evolution and thus life. Molecular evolution cannot be explained by starting with high concentrations of activated chemicals that react toward their chemical equilibrium; persistent non-equilibria are required to maintain continuous reactivity and we especially consider thermal gradients as an early driving force for Darwinian molecular evolution. The temperature difference across water-filled compartments implements a laminar fluid convection with periodic temperature oscillations that allow for the melting and replication of DNA. Simultaneously, dissolved molecules are moved along the thermal gradient by an effect called thermophoresis. The combined result is an efficient molecule trap that exponentially favors long over short DNA and thus maintains complexity. Future experiments will reveal how thermal gradients could actively drive the Darwinian process of replication and selection.

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