The alga, Didymosphenia geminata
, commonly referred to as "didymo", is a freshwater microscopic diatom. It is found in streams and rivers across much of North America.
Didymo attaches to the streambed by a stalk and it forms thick mats that can alter aquatic ecosystems. These mats have a rough texture similar to wet wool and
can look like strands of toilet paper.
In recent years, streams in New Zealand, North America, Europe, South America and Asia have noted unprecedented masses of "didymo". This diatom
is able to blanket up to 100% of stream surfaces by with thicknesses of greater than 8 inches, potentially altering physical and biological conditions within streams.
Contrary to other algae species, didymo represents an interesting paradox where didymo mats form under very low nutrient conditions.
Also, managers continue to grapple with how best to address this species when faced with extraordinary mat formations. As the scientific community continues to research
important aspects of didymo, we will share the latest research to help inform thoughtful management decisions.
Prevent the Spread of Didymo
Cleaning equipment between uses on different freshwater systems is important to prevent the spread of didymo and other invasive species. If you can follow the simple Inspect, Clean and Dry
steps, then you will do a world of good.
For decontamination methods specific to didymo, you can learn more from the links below in the report "Decontaminating Equipment". For more information on general cleaning practices, go to cleanangling.org