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 pelagic zone is separated into several subzones depending on water depth: 1  Epipelagic zone (ocean surface to 200 meters deep). This is the zone in which photosynthesis can occur, because light is available. 2  Mesopelagic zone (200-1,000m) - This is also known as the twilight zone, because light becomes limited.