Resources (Arabic)

Introduction to Freshwater Algae General introduction  Algae are widely present in freshwater environments, such as lakes and rivers.  They are typically present as micro-organisms visible only with the aid of a light microscope.  They have a major importance in the freshwater environment, both in terms of fundamental ecology and in relation to human use of natural resources.  The word ‘algae’ originates from the Latin word for seaweed and is now applied to a broad assemblage of organisms that can be defined both in terms of morphology and general physiology.  They are simple organisms, without differentiation into roots, stems and leaves and their sexual organs are not enclosed within protective coverings.  In terms of physiology, they are fundamentally autotrophic (obtaining all their materials from inorganic sources) and photosynthetic generating complex carbon compounds from carbon dioxide and light energy.  These organisms include both prokaryotes (cells lacking a membrane bound nucleus) and eukaryotes (cells with a nucleus plus typical membrane-bound organelles).