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]
Stress is a biological and psychological response experienced on encountering a threat that we feel we do not have the resources to deal with. A stressor is the stimulus (or threat) that causes stress, e.g. exam, divorce, death of loved one, moving house, loss of job. Sudden and severe stress generally produces: Increase in heart rate