Breathing from Underground: The Effect of Atmospheric Stability on Mass and Heat Transport in Termite Mounds

Termite mounds are massive, complex structures, built collectively by millions of minuscule insects – termites. The ventilation and gas-exchange function of these odd-shaped structures have been related to several phenomena including metabolism-driven natural convection within the mound, the effect of turbulent atmospheric wind flow on the mound superstructure, and the diurnally variable surface temperature and environmental conditions. In this study, we aim to use computational modeling to investigate the role of geometry, atmospheric stability, and turbulent intensity in the mound ventilation mechanism. We specifically focus on the termite mounds of the subfamily Macrotermitinae that are known for their massive cone-shaped, over-ground structures, believed to be built for the ventilation of the termites’ subterranean nest. Numerical simulations are performed over a simplified geometry, representing the key features of these mounds, exposed to the turbulent atmospheric wind flow. The internal and external flow features under different stability conditions are examined to reveal the diurnal variations of the heat and respiratory gas transport from the mound underground nest.