The drying out of a living organism. Such as a marine organism being exposed to air for abnormal periods of time or plants in a time of drought.
Marine intertidal organisms are often classified by their sensitivity to desiccation. Their location in the intertidal zone is directly related to their ability to remain out of the water for longer periods of time. For example, acorn barnacles have the ability to close their shell when exposed to air to prevent dessication. As a result they can often be found near the high tide line where they will not be underwater. In contrast, the Penpoint gunnel must remain below the low tide line or in tide pools that will consistently have water.