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.
coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals coral reefs are built by colonies of tiny animals found in marine waters that contain few nutrients most coral reefs are built from stony corals which in turn consist of polyps that cluster in groupsthe polyps belong to a group of animals known as cnidaria which also includes sea anemones and jellyfishoral reefs are built by colonies of tiny animals found in marine waters that contain few nutrients most coral reefs are built from stony corals which in turn consist of polyps that cluster in groups the polyps belong to a group of animals known as cnidaria which also includes sea anemones and jellyfish