INVESTIGADORES
MARTYNIUK Nicolas Alejandro
congresos y reuniones científicas
Título:
Nutrients, organic matter and bacteria community composition at early stages of the proglacial lake of Ventisquero Negro (Mountain Tronador, Patagonia, Argentina)
Autor/es:
MODENUTTI, B.; BASTIDAS NAVARRO, M.; MARTYNIUK, N.; BALSEIRO, E.
Lugar:
Turín
Reunión:
Congreso; SIL 2016; 2016
Institución organizadora:
International Society of Limnology: SIL
Resumen:
Climate change affects glaciers all over the world causing glacial recession with the formation of new lakes. These proglacial lakes are characterized by heavy glacial clay inputs that cause a turbidity-induced attenuation of photosynthetically active radiation (PAR), therefore they can be expected as environments with light limitation for primary producers. The aim of this study was to assess temporal shifts in nutrients, organic matter and bacteria abundance, diversity and respiration, in the proglacial lake of Ventisquero Negro located in Mountain Tronador (Patagonia, Argentina). Samplings were conducted during four successive austral summers (2012/15). We measured nutrient concentrations, bacteria abundances assessing different components of bacterial community structure using next-generation sequencing of the 16S rRNA gene. In addition we conducted experiments measuring oxygen consumption by bacteria communities and spectrofluorometric analysis of the dissolved organic matter. Results showed that chlorophyll a concentrations were low (0.571±0.33 µg L-1) because of the light limitation imposed by the high turbidity due to total suspended solids. Bacteria community analysis using the 16S rRNA gene identified a total of 2135 OTUs consisting mainly of Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. Dissolved organic carbon (DOC) concentrations in the lake were low (0.43± 0.16 mg L-1) and analyses indicated the presence of two components one corresponds to protein-like and the other to humic-like substances. Ice presented higher DOC concentration (1.6 ± 0.18 mgL-1) than the lake and analyses showed the dominance of protein-like component. High bacteria respiration rates were attained in coincidence with the presence of one protein-like component in the dissolved organic matter, while no relationship was observed between bacteria respiration and chlorophyll a concentration.