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Title

Tropical high-altitude Andean lakes located above the tree line attenuate UV-A radiation more strongly than typical temperate alpine lakes

Publication Year

2013

Author(s)
  • Aguilera, Ximena
  • Lazzaro, Xavier
  • Coronel, Jorge S.
Source
PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES Volume: 12 Issue: 9 Pages: 1649-1657 Published: 2013
ISSN
1474-905X eISSN: 1474-9092
Abstract

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.

Author Keyword(s)

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KeyWord(s) Plus
  • SOLAR ULTRAVIOLET-RADIATION
  • DISSOLVED ORGANIC-CARBON
  • CONSERVATION PRIORITIES
  • BIODIVERSITY HOTSPOTS
  • PHYTOPLANKTON
  • PHOTOSYNTHESIS
  • TRANSPARENCY
  • BOLIVIA
ESI Discipline(s)
  • Biology & Biochemistry
  • Chemistry
  • Molecular Biology & Genetics
Web of Science Category(ies)
  • Biochemistry & Molecular Biology
  • Biophysics
  • Chemistry, Physical
Adress(es)

[Aguilera, Ximena; Lazzaro, Xavier; Coronel, Jorge S.] Univ Mayor San Simon, Fac Ciencias & Tecnol, Dept Biol, Unidad Limnol & Recursos Acuat, Cochabamba, Bolivia; [Lazzaro, Xavier] UPMC, Museum Natl Hist Nat, UMR BOREA MNHN IRD 7208 207, CNRS, F-75231 Paris 05, France

Reprint Adress

Aguilera, X (reprint author), Univ Mayor San Simon, Fac Ciencias & Tecnol, Dept Biol, Unidad Limnol & Recursos Acuat, Calle Sucre & Parque Torre S-N, Cochabamba, Bolivia.

Country(ies)
  • Bolivia
  • France
CNRS - Adress(es)
  • Biologie des organismes et écosystèmes aquatiques (BOREA), UMR7208
Accession Number
WOS:000323174000010
uid:/5M1S5PZL
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