The Negative Ecological Impact Of The Invasive ‘Rock Snot’ Algae On The Ecosystems Of The Rivers


Only some small organisms of the rivers, such as the water hydra, are able to adapt to the ecological impact of invasive algae Didymosphenia geminata, popularly known as ‘Rock Snot’, according to a study conducted by the Spanish researchers from the University of Barcelona.

This new research is the most complete that has been done so far in systems ecology on such an exotic algae and, together with previous work of the group involved in this research, it constitutes a strategic tool to control the proliferation of the species and to avoid its presence in river stretches where it has not yet appeared.

The algae Didymosphenia geminata, or ‘Rock Snot’, is an exotic and invasive species of freshwater capable of covering the riverbed for miles. It is a diatom native to northern Europe and North America that lives mostly in very cold waters, which are clean and without phosphorus, and that generates large biomasses that alter the biodiversity and the functioning of fluvial ecosystems.

D. geminata is resistant to drying and can survive outside the water in extreme conditions of temperature and humidity. Detected in more than fifty countries of the temperate climate and cold zones, the ‘Rock Snot’ algae has caused critical episodes in New Zealand and the United States, where it has affected the migration of species of economic interest such as salmon.

‘Rock Snot’ formes layers of several centimeters thick which negatively affect the ecosystem of the rivers

The peculiarity of the ‘Rock Snot’ is that unlike what happens with most algae which grow when there is more phosphorus in the water, this one is able to proliferate in oligotrophic conditions (without phosphorus), favored by small increments of temperature or insolation.

The layers formed by ‘Rock Snot’ algae are several centimeters thick and completely alter the habitat of many organisms that use to live on stones, such as snails and insects.

The effects of the massive growth of ‘Rock Snot’ also affect fish such as trout, which has fewer options for feeding and laying eggs. As a result, only the small organisms that are capable of living in the mucus-like layers populate the rivers.

In conclusion, ‘Rock Snot’ (scientifically known as Didymosphenia geminata) has a huge negative ecological impact on the ecosystems of rivers, especially on those populated by trouts and/or salmons.


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