scholarly journals Evaluation of low-temperature geothermal potential in Utah and Goshen Valleys and adjacent areas, Utah : part II: water temperature and chemistry

1984 ◽  
1980 ◽  
Vol 1 ◽  
pp. 119-122 ◽  
Author(s):  
D. S. Russell-Head

Blocks of ice with the proportions of tabular icebergs have been observed melting in water of different temperatures and salinities. The sub-surface shape adopted by the blocks melting in water of the same salinity as sea-water was typically a ‘bath-tub’ one. The basal and mean-side melt rates were of a similar value. The melt rates obtained in the laboratory for icebergs in water of a low temperature match those inferred from population studies of Antarctic icebergs. The melt rate is proportional to the water temperature above the onset of freezing raised to the power 1.5 and melt rates at 18°C are likely to be greater than one metre per day.


2007 ◽  
Vol 64 (5) ◽  
pp. 793-802 ◽  
Author(s):  
Dennis S Thomsen ◽  
Anders Koed ◽  
Christian Nielsen ◽  
Steffen S Madsen

Brown trout (Salmo trutta) show large phenotypic plasticity. Juveniles may reside in their native freshwater habitat until maturation or migrate into the ocean as 1- to 3-year-old smolts. Sea-going fish (sea trout) reside at sea for 2–3 years until migrating back to their native stream for reproduction. However, immature fish may leave the ocean during their first or second winter at sea and overwinter in freshwater. The question is why does this occur? We tested the hypothesis that hypo-osmoregulatory capacity is compromised by low temperature in two coastal sea trout populations, one representing high salinity and the other, low salinity. Immature sea-run trout were caught in lower parts of two rivers during winter and acclimated to laboratory conditions. Subgroups were challenged with high salinity or low water temperature or both, and their osmoregulatory performance was investigated. Low temperature compromised the hypo-osmoregulatory ability, as indicated by insufficient compensatory adjustments of ion-transport mechanisms. Tagging experiments revealed that descent of overwintering fish into the ocean occurred over a narrow time period coincident with increasing water temperature. We conclude that overwintering in freshwater is partly driven by compromised osmoregulatory physiology, but because not all fish in a population do so, the phenomenon may also reflect diverging life strategies.


2021 ◽  
Author(s):  
Souta Nakajima ◽  
Masanao Sueyoshi ◽  
Shun K. Hirota ◽  
Nobuo Ishiyama ◽  
Ayumi Matsuo ◽  
...  

A key piece of information for ecosystem management is the relationship between the environment and population genetic structure. However, it is difficult to clearly quantify the effects of environmental factors on genetic differentiation because of spatial autocorrelation and analytical problems. In this study, we focused on stream ecosystems and the environmental heterogeneity caused by groundwater and constructed a sampling design in which geographic distance and environmental differences are not correlated. Using multiplexed ISSR genotyping by sequencing (MIG-seq) method, a fine-scale population genetics study was conducted in fluvial sculpin Cottus nozawae, for which summer water temperature is the determinant factor in distribution and survival. There was a clear genetic structure in the watershed. Although a significant isolation-by-distance pattern was detected in the watershed, there was no association between genetic differentiation and water temperature. Instead, asymmetric gene flow from relatively low-temperature streams to high-temperature streams was detected, indicating the importance of low-temperature streams and continuous habitats. The groundwater-focused sampling strategy yielded unexpected results and provided important insights for conservation.


1981 ◽  
Author(s):  
D.S. Hodge ◽  
R. De Rito ◽  
K. Hifiker ◽  
P. Morgan ◽  
C.A. Swanberg

2022 ◽  
Vol 2160 (1) ◽  
pp. 012032
Author(s):  
Hongxuan Li ◽  
Tonghua Zou ◽  
Qingling Hui ◽  
Ting Li ◽  
Walter Mittelbach

Abstract In recent years, adsorption refrigeration technology has attracted wide attention from experts and scholars at home and abroad due to its environmental friendliness and energy saving advantages. In order to study the effectiveness of adsorption refrigeration technology to recover low-grade energy, a silica gel-water adsorption refrigeration system was proposed, which can effectively utilize low-grade energy such as industrial waste heat. The structure and composition of the system are introduced. The operation performance of the unit is tested under different working conditions by orthogonal experimental method, and the experimental results are analyzed. The effects of hot water temperature and flow, chilled water temperature and flow on the refrigeration capacity and COP value of the system are obtained. The experimental results show that under the low-temperature heat source of 55-75°C, the cooling capacity of the system can reach 5.3-12 and the COP value can reach 0.36-0.56. Under the same hot water temperature difference, the cooling capacity and COP value of the system increase rapidly under the condition of changing the hot water temperature at low temperature, indicating that increasing the heat source temperature at low temperature has a greater impact on the system performance. Through the analysis of primary and secondary effects, it is concluded that the inlet temperature of hot water is the main factor affecting the refrigeration capacity and COP value of the system.


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