Limnological, phytoplankton and bathymetry characteristics of a coloured lake (Laguna Negra, National Park Tierra del Fuego, Argentina)
The 4% of the Argentinian sector from Tierra del Fuego is covered with water. Colored lakes are among the most conspicuous water bodies in the Andean area, and Laguna Negra, in the National Park Tierra del Fuego, is one of them. The main physical and chemical variables were monitored and phytoplankton samples were obtained with a monthly frequency during the ice-free period, between September 2016 and March 2018 (n=15). Laguna Negra was deeper than expected, with a maximum depth of 15.5 m. In addition, this lake has high pH values (7.5±0.55), which were quite stable during the study (variation coefficient, VC=8.3%). These characteristics preclude us from considering this lake as a shallow peatland lake. Dissolved and total nutrients were low and did not show a temporal pattern of fluctuation during the study period. The same trend of no clear fluctuation was also shared by dissolved organic carbon concentration (DOC=7.7±0.78 mg/L). Taxa richness ranged between 6 and 13 throughout the study. The biovolume was inversely correlated with the vertical attenuation coefficient of light (Kd). Phytoplankton biomass (chlorophyll-a concentration, abundance, and biovolume) was generally low, with Dinobryon divergens, Mallomonas sp. and Parvodinium cf. inconspicuum being the dominant taxa. Depending on the classification used, Laguna Negra might be regarded as a humic or dystrophic lake because its color is at the edge of values used in the current literature to consider a lake as humic.
| Main Authors: | , , , , , , , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Asociación Argentina de Ecología
2023
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| Online Access: | https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/2014 |
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