Impact of thermal convection on air circulation in a mammalian burrow under arid conditions

Ganot, Yonatan; Dragila, M. I.; Weisbrod, Noam

doi:10.1016/j.jaridenv.2012.04.003

Cited by 20 publications

(10 citation statements)

References 31 publications

(47 reference statements)

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“…Heat production related to highly exothermic sulfide oxidation increases the temperature and thus leads to thermal gas convection and subsequent changes in O 2 fluxes within the waste rock (Lahmira et al, 2007; Lahmira, 2010; Lahmira and Lefebvre, 2014). Ganot et al (2012), in a different context, showed a similar impact of thermal convection on air circulation and O 2 supply in a mammalian burrow under arid conditions. Similarly, Lahmira et al (2014) showed that the convective air flow through a reclamation cover over an unsaturated coke dump at an oil sands mine can have an impact on the water distribution within the cover, resulting in additional moisture losses beyond those expected by evapotranspiration, thus causing accelerated drying of the cover.…”

Section: Gas Flow In Waste Rock Dumpsmentioning

confidence: 78%

Atmospheric Controls on Gas Flow Directions in a Waste Rock Dump

Lahmira

Lefebvre

Hockley³

et al. 2014

Vadose Zone Journal

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A fatal accident at a mine waste rock dump was thought to be due to the downward low of O 2deicient air originating from the dump. A numerical model tested the plausibility of various physical mechanisms hypothesized to control gas low in the dump. The main initial hypotheses were that gas low leading to the incident was due to the sole or combined effect of changes in barometric pressure, temperature, or till cover water saturation.

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Section: Gas Flow In Waste Rock Dumpsmentioning

confidence: 78%

Atmospheric Controls on Gas Flow Directions in a Waste Rock Dump

Lahmira

Lefebvre

Hockley³

et al. 2014

Vadose Zone Journal

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“…The Journal of Experimental Biology (2014) gradients could drive convection through the burrow (Ganot et al, 2012). However, Ganot and colleagues used only straight, augur-dug holes with single openings in their study, which are not characteristic of jird burrow architecture, which in itself may affect the onset and intensity of thermal convection.…”

Section: Research Articlementioning

confidence: 99%

“…Unlike unoccupied M. crassus burrows (Shenbrot et al, 2002), the temperature inside the nest chambers reported by Brickner-Braun (Brickner-Braun, 2014) was higher than T a throughout the day, suggesting that the presence of the female and litter caused a substantial rise in temperature in their immediate environment because of their metabolic heat production. The steep temperature gradient between an occupied chamber and the ambient air could potentially promote and enhance ventilation by thermal convection (Kleineidam et al, 2001;Turner, 2001;Ganot et al, 2012). However, it appears that this is not an important mechanism for ventilation in occupied jird burrows, as maximum [CO 2 ] values were reached at night before sunrise, in spite of the large differences between T a and burrow temperature.…”

Section: Research Articlementioning

confidence: 99%

Ventilation of multi-entranced rodent burrows by boundary layer eddies

Brickner-Braun

Zucker-Milwerger

Braun

et al. 2014

Journal of Experimental Biology

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Rodent burrows are often assumed to be environments wherein the air has a high concentration of CO 2 . Although high burrow [CO 2 ] has been recorded, many studies report burrow [CO 2 ] that differs only slightly from atmospheric concentrations. Here, we advocate that one of the reasons for these differences is the penetration into burrows of air gusts (eddies), which originate in the turbulent boundary layer and prevent build-up of CO 2 . We have characterized the means by which burrows of Sundevall's jird, which are representative of the burrows of many rodent species with more than one entrance, are ventilated. Our results demonstrate that, even at low wind speeds, the random penetration of eddies into a burrow through its openings is sufficient to keep the burrow [CO 2 ] low enough to be physiologically inconsequential, even in its deep and remote parts.

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“…Several mechanisms can drive advective gas exchange at the borehole‐atmosphere interface and inside a borehole or cavity. These include (1) barometric pumping, which is the inward and outward motion of subsurface air due to cycles in atmospheric pressure (Mourzenko et al, ; Neeper, ; Perina, ; Rossabi & Falta, ); (2) thermal‐induced convection (TIC), also referred to as free convection, which initiates when there are unstable density gradients resulting from temperature differences between the atmospheric air and that within underground voids, such as porous media or boreholes (Calonne et al, ; Ganot et al, ; Luetscher et al, ; Luetscher & Jeannin, ; Nachshon et al, ; Weisbrod et al, ; Weisbrod & Dragila, ); and (3) wind‐induced convection (WIC) within a cavity that is driven by pressure differences generated from surface winds (Amos et al, ; Ishihara et al, ; Nachshon et al, ; Reicosky et al, ).…”

Section: Introductionmentioning

confidence: 99%

Mechanisms Controlling Air Stratification Within a Large Diameter Borehole and Atmospheric Exchange

et al. 2018

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Large boreholes dot the landscape across much of the arid low latitudes. Here we explore air dynamics within these features to understand their significance to gas transport at the Earth‐atmosphere interface. We instrumented a large‐diameter (3.4 m) borehole and the borehole‐atmosphere interface to explore under natural conditions the role of atmospheric variability on gas transport down to the water table at a depth of 59 m. Two independent tracers that naturally existed inside the borehole, water vapor and CO2, were used to map diffusive and advective transport regions and rates. We hypothesize that temporal variations in atmospheric and borehole air temperature determine the transport regime; thus, we conducted two separate 1‐month observations, during summer and winter. Of several potential air transport mechanisms known to act within cavities, thermal‐induced convection (TIC) was found to be the dominating advective mechanism inside the borehole. During winter, TIC circulated atmospheric air throughout the entire borehole down to the water table. During summer, however, atmospheric air reached only down to the middle of the borehole, indicating stable stratification below that depth; TIC was limited to the upper mixed layer overlying a diffusive transport layer. During times when TIC was suppressed, the stratified borehole air developed relatively low temperatures, and accumulated elevated CO2 concentrations and high vapor content, which were then vented to the atmosphere during convective active periods.

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Impact of thermal convection on air circulation in a mammalian burrow under arid conditions

Cited by 20 publications

References 31 publications

Atmospheric Controls on Gas Flow Directions in a Waste Rock Dump

Atmospheric Controls on Gas Flow Directions in a Waste Rock Dump

Ventilation of multi-entranced rodent burrows by boundary layer eddies

Mechanisms Controlling Air Stratification Within a Large Diameter Borehole and Atmospheric Exchange

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