Definition. The normal concentration of sodium in the blood plasma is 136-145 mM. Hyponatremia occurs when sodium falls below 130 mM. Plasma sodium levels of 125 mM or less are dangerous and can result in seizures and coma. Description. Sodium is an atom, or ion, that carries a single positive charge.
reef1. 1  a ridge of rocks or sand, often of coral debris, at or near the surface of the water. 2  Mining. a lode or vein.
From Wikipedia, the free encyclopedia. The Reef is a 2010 Australian horror film. The film was written and directed by Andrew Traucki, his second feature film (the first being Black Water), and is about a group of friends who capsize while sailing to Indonesia.