Publications des scientifiques de l'IRD

Aguilera X., Lazzaro Xavier, Coronel J.S. (2013). Tropical high-altitude Andean lakes located above the tree line attenuate UV-A radiation more strongly than typical temperate alpine lakes. Photochemical and Photobiological Sciences, 12 (9), p. 1649-1657. ISSN 1474-905X.

Titre du document
Tropical high-altitude Andean lakes located above the tree line attenuate UV-A radiation more strongly than typical temperate alpine lakes
Année de publication
2013
Type de document
Article référencé dans le Web of Science WOS:000323174000010
Auteurs
Aguilera X., Lazzaro Xavier, Coronel J.S.
Source
Photochemical and Photobiological Sciences, 2013, 12 (9), p. 1649-1657 ISSN 1474-905X
Tropical high-altitude Andean lakes are physically harsh ecosystems. Located above the treeline (>= 4000 m a.s.l.), they share common features with temperate alpine lakes, which impose extreme conditions on their aquatic organisms: e. g., strong winds, broad diel variations in water temperature, and intense solar ultraviolet radiation (UVR). However, because of their latitude, they differ in two major ecological characteristics: they lack ice cover during the winter and they do not present summer water column stratification. We sampled 26 tropical high-altitude Andean lakes from three regions of the Bolivian Eastern Andes Cordillera during the wet period (austral summer). We performed an ordination to better describe the typology of Andean lakes in relation to the environmental variables, and we assessed the relationships among them, focussing on the UV-A transparency (360 nm) throughout the water column. We found a positive correlation between UV-A transparency calculated as Z(1%) (the depth which reaches 1% of the surface UV-A), the lake maximum depth and Secchi transparency (r = 0.61). Z(1%) of UV-A was smaller in shallow lakes than in deep lakes, indicating that shallow lakes are less transparent to UV-A than deep lakes. We hypothesize that, compared to shallow lakes, deep lakes (maximum depth > 10 m) may have lower dissolved organic carbon (DOC) concentrations (that absorb UV radiation) due to lower temperature and reduced macrophyte cover. Based on our data, tropical high-altitude Andean lakes are less transparent to UV-A (K-d range = 1.4-11.0 m (1); Z(1%) depth range = 0.4-3.2 m) than typical temperate alpine lakes (1-6 m (1), 3-45 m, respectively). Moreover, they differ in vertical profiles of UV-A, chlorophyll-a, and temperature, suggesting that they may have a distinct ecological functioning. Such peculiarities justify treating tropical high-altitude Andean lakes as a separate category of alpine lakes. Tropical high-altitude Andean lakes have been poorly studied. Thus they deserve more in-depth studies in the face of global changes regarding the use of their UV transparency as a sentinel proxy of climate changes, particularly global warming.
Plan de classement
Ecologie, systèmes aquatiques [036]
Description Géographique
ANDES ; ZONE TROPICALE ; BOLIVIE
Localisation
Fonds IRD ; La Paz
Identifiant IRD
fdi:010062200
Contact