When an atom loses electron(s) it will lose some of its negative charge and so becomes positively charged. A positive ion is formed where an atom has more protons than electrons. In the opposite case when an atom gains electron(s) it becomes negatively charged (more electrons than protons).
Cyanobacteria also known as Cyanophyta are responsible for fixing nitogen and raising phosphorus level through mineralization they are also called blu-green-algae. They commonly obtain their energy from 'oxygenic' photosynthesis.