scholarly journals Photosynthetic performance of Colobanthus quitensis (Kunth) Bartl. (Caryophyllaceae) in a high-elevation site of the Andes of central Chile

Author(s):  
M. ANGÉLICA CASANOVA-KATNY ◽  
LEÓN A BRAVO ◽  
MARCO MOLINA-MONTENEGRO ◽  
LUIS J CORCUERA ◽  
LOHENGRIN A CAVIERES
1975 ◽  
Vol 14 (70) ◽  
pp. 155-170 ◽  
Author(s):  
Cesar N. Caviedes ◽  
Roland Paskoff

The extension of the Quaternary glaciations has been studied in the semi-arid Andes of north-central Chile, where the glacial modelling is striking. In the Elqui valley (lat. 30°S.), two glacial advances were identified reaching down to 3 100 m (Laguna glaciation) and 2 500 m (Tapado glaciation). In the Aconcagua valley (lat. 33°S.), moraines from three major glacial advances were found, at 2 800 m (Portillo glaciation), 1 600 m (Guardia Vieja glaciation) and 1 300 m (Salto del Soldado glaciation).The Quaternary glaciations were linked with a decrease of temperature, but more significantly with a marked increase of precipitation probably related to an equatorward shift of 5–6 degrees of the austral polar front. The results obtained in the semi-arid Chilean Andes are correlated with those recently reported from other sectors of the southern Andes.


2012 ◽  
Vol 124 (2) ◽  
pp. 366-370 ◽  
Author(s):  
David F. Vogt ◽  
Mark E. Hopey ◽  
G. Rad Mayfield ◽  
Eric C. Soehren ◽  
Laura M. Lewis ◽  
...  

2021 ◽  
Author(s):  
Francesca Pittino ◽  
Michael Seeger ◽  
Roberto Azzoni ◽  
Roberto Ambrosini ◽  
Andrea Franzetti

AbstractCryoconite holes, ponds full of melting water with a sediment on the bottom, are hotspot of biodiversity of glacier surface. They host a metabolically active bacterial community that is involved in different dynamics concerning glacier ecosystems. Indeed, they are responsible of organic matter production and with other microorganisms establish a real microecosystem. Cryoconite holes have been described in different areas of the world (e.g., Arctic, Antarctic, Alps, Himalaya), and with this study we will provide the first description of bacterial communities of cryoconite holes of the Andes in South America. We collected samples on three high elevation glaciers of the Andes (Iver, Iver East and Morado glaciers) and two Patagonian glaciers located at sea level (Exploradores glacier and Perito Moreno). Results show that the most abundant orders are Burkholderiales, Cytophagales, Sphingobacteriales, Actinomycetales, Pseudomonadales, Rhodospiarillales, Rhizobiales, Sphingomonadales and Bacteroidales, which have been reported on glaciers of other areas of the world, Bacterial communities change from one glacier to another and both water pH and O2 concentration affect bacterial communities composition.


2013 ◽  
Vol 9 (3) ◽  
pp. 2277-2308
Author(s):  
R. de Jong ◽  
L. von Gunten ◽  
A. Maldonado ◽  
M. Grosjean

Abstract. High-resolution reconstructions of climate variability that cover the past millennia are necessary to improve the understanding of natural and anthropogenic climate change across the globe. Although numerous records are available for the mid- and high-latitudes of the Northern Hemisphere, global assessments are still compromised by the scarcity of data from the Southern Hemisphere. This is particularly the case for the tropical and subtropical areas. In addition, high elevation sites in the South American Andes may provide insight into the vertical structure of climate change in the mid-troposphere. This study presents a 3000 yr long austral summer (November to February) temperature reconstruction derived from the 210Pb and 14C dated organic sediments of Laguna Chepical (32°16' S/70°30' W, 3050 m a.s.l.), a high-elevation glacial lake in the subtropical Andes of central Chile. Scanning reflectance spectroscopy in the visible light range provided the spectral index R570/R630, which reflects the clay mineral content in lake sediments. For the calibration period (AD 1901–2006), the R570/R630 data were regressed against monthly meteorological reanalysis data, showing that this proxy was strongly and significantly correlated with mean summer (NDJF) temperatures (R3yr = −0.63, padj = 0.01). This calibration model was used to make a quantitative temperature reconstruction back to 1000 BC. The reconstruction (with a model error RMSEPboot of 0.33 °C) shows that the warmest decades of the past 3000 yr occurred during the calibration period. The 19th century (end of the Little Ice Age (LIA)) was cool. The prominent warmth reconstructed for the 18th century, which was also observed in other records from this area, seems systematic for subtropical and southern South America but remains difficult to explain. Except for this warm period, the LIA was generally characterized by cool summers. Back to AD 1400, the results from this study compare remarkably well to low altitude records from the Chilean Central Valley and Southern South America. However, the reconstruction from Laguna Chepical does not show a warm Medieval Climate Anomaly during the 12–13th century, which is consistent with records from tropical South America. The Chepical record also indicates substantial cooling prior to 800 BC. This coincides with well-known regional as well as global glacier advances which have been attributed to a grand solar minimum. This study thus provides insight into the climatic drivers and temperature patterns in a region for which currently very few data are available. It also shows that since ca AD 1400, long term temperature patterns were generally similar at low and high altitudes in central Chile.


2018 ◽  
Vol 33 (2) ◽  
pp. 150-165 ◽  
Author(s):  
Rachel J. Tiner ◽  
Robert M. Negrini ◽  
Jose L. Antinao ◽  
Eric McDonald ◽  
Antonio Maldonado

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