New sampling campaign in lakes of glacial origin

Panoramic view of the Laguna Grande de Gredos (Ávila). Ignasi Arranz

A scientific team from the Global Change Research Institute (IICG) of the Rey Juan Carlos University has begun its third year of periodic data collection and sampling activities in eight lagoons on the Iberian Peninsula.

Irene Vega

This year's campaign, which begins in September, will maintain the objectives of the two previous campaigns and the sampling methodology will be identical to make the comparison between the lakes studied. However, the scientific team has added several elements that will complement the previous sampling campaigns to have a more general view of the lake systems of glacial origin.

The main objective of this activity, which is part of the FRESCO and FRESHRESTORE projects, is to improve the understanding of changes in the structure, stability and functioning of food webs in lake systems. “The ability to predict these changes will allow us to improve our knowledge of the main factors and mechanisms responsible for the functioning of aquatic ecosystems and the preservation of the biodiversity of these biomes,” explains Dr. Ignasi Arranz, principal investigator of the FRESCO project.

In the current campaign, a total of eight lagoons of the Iberian Peninsula will be sampled, with the particularity that some do not have fish (Cuadrada, Negra and Camposagrado), while in others there are salmonid species such as the common trout (psalm trutta) or endemic cyprinids (Trampal 3, Peces, Yeguas, Payón and Grande). “In the previous campaign, Caballeros was the only lagoon that did not have fish. In this sense, the samples obtained from the current campaign will allow a comparison to be made between trophic networks with and without fish in lagoons of glacial origin,” says Dr. Javier Sánchez-Hernández, principal investigator of the FRESHRESTORE project.

New for the 2024 campaign

This year's priority will be to sample the lagoons without any fish species and collect samples of the microbial communities. In addition, flow cytometry analysis (a laboratory method to determine the number of cells and certain characteristics such as their size and shape) and DNA/RNA barcoding (metabarcoding) in microbial communities to determine their size structure and taxonomic diversity.

The scientific team will also have the addition of a new member to the sampling group - hired by the FRESCO project - to complement the areas of knowledge and support the study of microbial communities. Dr. Guillermo García Gómez is an expert in ecophysiology and will participate in obtaining samples and analyzing microbial communities.

Collaboration between research projects

The sampling campaign of the lagoons is part of the collaborative effort between two research projects led by the URJC: FRESCO (Understanding food webs, and community structure in changing freshwater ecosystems: a macroecological perspective), funded by the Community of Madrid (2022-T1 / AMB-24100), and FRESHRESTORE (Holistic evaluation and restoration measures of human impacts on freshwater ecosystems across biogeographical gradients, funded by the European Union BiodivRestore COFUND Action programme (PCI2022-132991).

To date, two sampling campaigns have been carried out. The first was carried out between September and October 2022 in three lake systems: Laguna Grande, Laguna Cimera and Lake Sanabria. The second sampling campaign was carried out in eight lake systems in the centre of the Iberian Peninsula (Barco, Caballeros, Duque, Grande, Nava, Sanabria, Trampal 1 and Trampal 2), between September and October 2023.

Currently, the research work is in a phase focused on data collection and laboratory analysis. In addition, the results have already been published. first results. “In the Laguna del Duque, an unusual feeding strategy was detected for the first time in the bordallo (Squalius carolitertii), a species of fish from the cyprinidae family endemic to the Iberian Peninsula. Remains of a micromammal and other unidentified fish were observed in the stomachs of several individuals from the bordallo," explains Dr. Javier Sánchez-Hernández.

Other results are still in preparation or undergoing peer review in the scientific journal Hydrobiologia. “The topics of these works are diverse and include an ecological comparison between the common trout (psalm trutta), a native fish species, and the char (Salvelinus fontinalis), an invasive fish species in the Iberian Peninsula,” concludes Dr. Javier Sánchez-Hernández.

Regarding laboratory work, the 2023 samples have been processed by the research staff hired in charge of the FRESHRESTORE project and by several students from the Rey Juan Carlos University for the completion of their respective final degree and master's theses.