Total natural gas rig count in the US (including conventional gas drilling) Shale gas is natural gas that is found trapped within shale formations. Shale gas has become an increasingly important source of natural gas in the United States since the start of this century, and interest has spread to potential gas shales in the rest of the world.
A stressor is a chemical or biological agent, environmental condition, external stimulus or an event that causes stress to an organism.[1]
(December 2009). A stressor is a chemical or biological agent, environmental condition, external stimulus or an event that causes stress to an organism.An event that triggers the stress response may include: 1  environmental stressors (hypo or hyper-thermic temperatures, elevated sound levels, over-illumination, overcrowding).2  daily stress events (e.g., traffic, lost keys, quality and quantity of physical activity).n event that triggers the stress response may include: 1  environmental stressors (hypo or hyper-thermic temperatures, elevated sound levels, over-illumination, overcrowding). 2  daily stress events (e.g., traffic, lost keys, quality and quantity of physical activity).