Definition: A forest biome is a terrestrial biome which includes, across its entire spatial extent, densely packed vegetation which strongly limits light penetration to the forest floor.
Definition: Organic matter in soil which has reached a point of stability, where it will break down no further and might, if conditions do not change, remain essentially as it is for centuries, or millennia.
Definition: A sheet of saline water separated from the open sea by sand or shingle banks. The sheet of water between an offshore reef, especially of coral and mainland. The sheet of water within a ring or horseshoe shaped atoll.
