What unit is dissolved oxygen measured in?

Water Rangers measures dissolved oxygen, or DO2, in milligrams/litre.

Different measurements of DO2 will mean different circumstances for life in a water body, shown below;

• 0-2 mg/L: not enough oxygen to support life
• 2-4 mg/L: only a few fish and aquatic insects can survive
• 4-7 mg/L: good for many aquatic animals, low for cold water fish
• 7-11 mg/L: very good for most stream fish

For more an introduction, our protocol, and additional information regarding dissolved oxygen, we encourage you to visit our dissolved oxygen parameter page!