A team of researchers carried out various samplings of ‘didymo’ in rivers of Torres Del Paine and Tierra del Fuego. Although it is not yet known how this species reached the extreme south of the American continent, the phenomenon brings with it a series of negative consequences for ecosystems.

The “didymo” or “rock snot” is an invasive freshwater microalgae. In Chile, it was found for the first time in 2010 in the Espolón River, located in the Los Lagos Region. From that time to the present, this benthic diatom has expanded its range up to 3,000 km.

Its scientific name is Didymosphenia geminata, it has a viscous appearance, it is brown in color and although it is not known with certainty how it arrived in Patagonia, it is clear that it is capable of producing large blooms in freshwater rivers and streams. The main problem of this phenomenon, in addition to affecting the scenic beauty of the places it reaches, is the displacement of the native flora and that makes it difficult for the fish that live in the affected sectors to spawn.

As a result of the above, scientists from the Center for Dynamic Research of High Latitude Marine Ecosystems (IDEAL) of the Austral University of Chile (UACh) and the Federico Santa María Technical University (USM) carry out a collaboration to understand the process invasion of this species and look for technological alternatives as an opportunity. In this framework, the doctoral and master’s students, Romina Fuentes and Elías Reinoso, respectively, traveled to the Magallanes Region and Chilean Antarctica to carry out various samplings in the Serrano (Torres Del Paine) and Grande (Tierra del Fuego) rivers.

“We are interested in understanding the ecological and genetic factors that favor the proliferation of ‘didymo’ in Chile. With this objective, we have studied the relationship of this microalgae with the communities of microorganisms in the rivers of Patagonia, the genetic differentiation with other populations of the species in the world, and now we want to advance in understanding metatranscriptomics and its effect on the proliferation of what we know as kills,” explains Dr. Leyla Cárdenas, dean of the UACh Faculty of Sciences and researcher at the IDEAL Center.

For its part, the USM team is working on finding technological alternatives in which the ‘didymo’ can be used. “Within the framework of my thesis, I have developed a nanostructured membrane that contains a ‘didymo’ substance as an active material for the adsorption of metals in solution such as lead and with the potential capacity to absorb other metals such as cadmium, nickel and copper, among others and now with the VIU project that we were awarded we want to test the capture of impurities in lithium brine such as calcium and magnesium,” explains Reinoso.

The USM team is working on finding technological alternatives in which the ‘didymo’ can be used. © Cristóbal Arredondo

With the samples obtained in Torres Del Paine and Tierra Del Fuego, the researchers will replicate experiments to evaluate the effect of different physicochemical conditions on the shape of the bush. In addition, they will carry out analyzes in order to obtain the complete profile of the gene expression of the community of microorganisms associated with the ‘didymo’ bush. In parallel, they will develop nanostructured membranes and carry out adsorption experiments, which will allow them to continue validating the technology.

Rivers of Patagonia

Between 2015 and 2016, the team of researchers made the first visits to different rivers in Chile. However, there was one area in particular that caught their attention: The Magallanes Region; since it is an extreme zone and with characteristics where it was thought that it was difficult for the ‘didymo’ to grow.

Likewise, the rivers of this part of Patagonia are important bodies of water that harbor a unique biological diversity and where it is relevant to know how an invasion process affects their communities.

Through these studies, the researchers seek to understand the life cycle and the factors that favor the ‘didymo,’ with the aim of contributing to the generation of knowledge to create control and remediation strategies in the affected aquatic ecosystems and public policies for prevention of contamination of water bodies free from invasion.