Biodiversity in ground waters.

Despite the importance of ground waters in the global water cycle, their ecology and biodiversity have only recently received attention. Three areas are currently being studied: (I ) the origin and colonization ground ground waters, (2) the adaptation of animals to the subterranean environment, and (3) the role of ecotone between surface and ground waters. There are still several gaps in our knowledge of groundwater biodiversity (at the genetic level, the species level, the functional group level and the ecosystem level) to which future research must be directed.