The vagal response is an automatic reflex that happens within your body when your vagas nerve is stimulated. This reflex affects your central and peripheral nervous system, as well as your cardiovascular system and therefore a sudden stimulation of this reflex can set off a variety of symptoms.
Deep sea zones. The deep sea or deep layer is the lowest layer in the ocean, existing below the thermocline and above the seabed, at a depth of 1000 fathoms (1800 m) or more. Little or no light penetrates this part of the ocean, and most of the organisms that live there rely for subsistence on falling organic matter produced in the photic zone.
The mesopelagic zone is one of the five major vertical divisions of the oceans. The nominal depth delineation of this zone is between 200 and 1000 meters below the ocean surface. Due to the limited sunlight penetration to the depths of this zone, it is frequently termed the twilight zone. The ocean zone above the mesopelagic is known as the epipelagic zone and the vertical region immediately below is the bathypelagic zone.