Dolichospermum macrosporum is a filamentous cyanobacterium commonly found in freshwater environments like ponds, lakes, and slow-moving rivers. It forms straight or slightly curved trichomes composed of cylindrical or barrel-shaped cells, typically 3 to 6 micrometers wide and 10 to 30 micrometers long. The trichomes contain specialized heterocysts for nitrogen fixation and produce akinetes, which are thick-walled resting spores for survival during adverse conditions. Cells exhibit a blue-green color due to chlorophyll a and phycobiliproteins. This species plays a vital ecological role in nutrient cycling and supports aquatic ecosystems through photosynthesis and nitrogen fixation.