Glacial influence affect modularity in bacterial community structure in three deep Andean North- Patagonian lakes

MODENUTTI, B.,; MARTYNIUK, N; BASTIDAS NAVARRO, M.,; BALSEIRO, E

Palma de Mallorca

Congreso; ASLO AQUATIC MEETING 2023; 2023

Universidad de Isaas Baleares

We analyze the bacteria community composition and theecological processes structuring these communities in three deep mountain lakesthat receive meltwater from the glaciers of Mount Tronador (North-Patagonia,Argentina). Lakes differ in their glacial connectivity and in their turbiditydue to glacial particles. Lake Ventisquero Negro is a recently formedproglacial lake and it is still in contact with the glacier. Lakes Mascardi andFrías lost their glacial connectivity during the Pleistocene-Holocenetransition. Total dissolved solid concentration has a significant contributionto the environmental gradient determining the segregation of the three lakes.The net relatedness index (NRI) showed that the bacterial community of lakeVentisquero Negro is determined by environmental filtering, while in the otherlakes, species interaction would be a more important driver. The co-occurrencenetwork analysis showed an increase in modularity and in the number of moduleswhen comparing Lake Ventisquero Negro with the two large glacier-fed lakessuggesting an increase in heterogeneity. At the same time, the presence of modules with phototrophic bacteria(Cyanobium strains) in lakes Frías and Mascardi would reflect the increase ofthis functional photosynthetic association. Overall, our results showed that the reduction in ice masses inPatagonia will affect downstream large deep piedmont lakes losing the glacialinfluence in their bacterial communities.