A light micrograph (polarized light) of a colonial cyanobacteria Gloeotrichia sp. Gloeotrichia is a freshwater Cyanobacteria. In many parts of the world, Gloeotrichia appears unexpectedly in many lakes during late summer and fall as lgae bloom". Gloeotrichia also has the ability to produce compounds called icrocystins?which are powerful toxins. There are many records of livestock, dogs and humans suffering liver damage through ingesting contaminated water. Magnification: x140 when printed at 10 centimetres wide at its longest edge.