Ascotán and Carcote salt flats as sensors of humidity fluctuations and anthropic impacts in the transition zone of the Andean Altiplano

Flores-Varas, Abraham; Heine-Fuster, Inger; López-Allendes, Camila; Pizarro, H.; Castro, Daniela V.; Luque, José A.; Aránguiz-Acuña, Adriana

doi:10.1016/j.jsames.2020.102934

Cited by 9 publications

(9 citation statements)

References 52 publications

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“…The k values were primarily influenced by the concentration of ferromagnetic minerals. The Fe and Ti curves were comparatively similar for all sites and these minerals were present in relatively high concentrations, suggesting that the primary magnetic phase in the sediments may be (titano)magnetite and/or (titano)maghemite, which coincides with the ferromagnetic minerals recorded in surrounding volcanic rocks 28 , 32 . No significant variations were observed in the composition throughout the sections.…”

Section: Resultsmentioning

confidence: 53%

“…On a millennial scale, wetter to drier periods have been identified from lake sediments using a multiproxy approach that included the analysis of isotopic and magnetic properties and the study of biological proxies such as fossil plant cover and diatom assemblages, as recorded from the Salar de Uyuni sediments 21 , 22 and Lake Titicaca 23 , 24 . For shorter timescales, decadal phenomena such as the ENSO have been identified through sedimentary records 25 , as have recent anthropic disturbances including the intensive mining activities in the Atacama Desert on lacustrine sediments and the biotic communities of the Inca Coya Lake 26 , 27 and the Ascotán salt flat 28 .…”

Section: Introductionmentioning

confidence: 99%

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Limnological response from high-altitude wetlands to the water supply in the Andean Altiplano

García-Sanz

Heine-Fuster

Luque

et al. 2021

Sci Rep

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The Andean Altiplano-Puna is located at an elevation of approximately 4000 m.a.s.l. and is delineated by the Western and the Eastern Andes Cordillera. The high-altitude wetlands (HAWs) in the Central Andes are unique ecosystems located in the Altiplano that provide many ecosystem services. The objective of this study was to characterize the spatial heterogeneity of the environmental conditions associated with varying hydrology of the HAW, Salar de Tara, in the Andean Altiplano. Sediment samples of up to 20 cm in depth were obtained from various salt flat sub-environments. The samples were analyzed using proxies for mineralogical and chemical composition, thermal analysis, and magnetic susceptibility. Diatom and ostracod communities were also identified and analyzed. The results reflected changes in the geochemistry, carbon content, mineralogy, and magnetic properties of the sediments that can be explained by variations in the sources of water input to the Salar de Tara. The sub-environments depend on the supply of water via the groundwater recharge of springs adjacent to the streamflow from the Zapaleri River, which promotes greater diversity and richness of genera. Our results suggest that water extraction at industrial levels greatly impacts the persistence of hydrologically connected HAWs, which concentrate a worldwide interest in brine mining.

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Section: Resultsmentioning

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Limnological response from high-altitude wetlands to the water supply in the Andean Altiplano

García-Sanz

Heine-Fuster

Luque

et al. 2021

Sci Rep

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“…The overlap of the diatom community guilds in some sites (NMDS results, Figure 3) shows similarity between the community assemblages of the salt flats, which may be explained by their proximity and climatic, geomorphological, and other regional shared histories (Flores-Varas et al, 2021). The main differences could be related to the anthropic disturbances present in Ascotán, where there has been a historical water and brine extraction (Servicio Nacional de Geología y Minería, 2017), producing an additional hydric stress (Acosta and Custodio, 2008) that would decrease the ecological richness of the system (Marazuela et al, 2020).…”

Section: Community Composition and Similaritymentioning

confidence: 91%

“…Both salt flats are fed by springs that discharge groundwater from the nearby volcanic aquifers, mainly recharged from seasonal rainfall, snowmelt, and sporadic rainfall events, and through the drainage network that provides water and sediments by hydrological erosion, triggering the development of alluvial fans. The Ascotán and Carcote basins are connected hydrogeologically and, because of their spatial proximity, are exposed to the same climatic conditions, yet they exhibit local, distinct physicochemical behaviors (Flores-Varas et al, 2021). An additional difference between these basins is the degree of anthropic disturbance, as Ascotán has been exploited for boron extraction since 1883 (Chong et al, 2010), while Carcote has not been subject to disturbance by industrial extraction.…”

Section: Study Areamentioning

confidence: 99%

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Differentiation of Diatom Guilds in Extreme Environments in the Andean Altiplano

Heine-Fuster

López-Allendes

Aránguiz-Acuña

et al. 2021

Front. Environ. Sci.

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The Andean Altiplano is characterized by its isolation, high altitude (>3,600 m a.s.l.), and a unique biodiversity, containing water systems such as lakes, rivers, wetlands, and salt flats. Near the southernmost area of the Andean Altiplano are two salt flats, Carcote and Ascotán, the former almost undisturbed by human intervention and the latter historically intervened with by brine mining. These mining activities deplete, pollute, and alter water flow, suggesting a significant threat to ecosystem functions. With regard to identifying the main factors promoting biotic community differentiation in these salt flats at different levels of human intervention, the aim of this study was to compare diatom community indices by guild (high-profile, low-profile, and motile) between these systems with a functional perspective, their relationship to environmental conditions, and the potential anthropic impact on their community structures. Diatom guilds were compared between salt flats based on their diversity, species richness, and abundance relative to ionic concentrations and granulometry. Beta diversity and the percentages of nestedness and turnover for each guild were also estimated. Results showed significant differences in ecological variables between the two salt flats. The largest values of species abundance, richness, and diatom diversity were measured in Carcote, suggesting greater primary productivity and diversity. The results also showed that the species composition of the motile guild was more differentiated between salt flats than those of other guilds (with the greatest diversity and richness), suggesting that motile diatoms are a key guild in maintaining the diatom community and that species from this guild are more sensitive to local conditions from each salt flat. Additionally, beta diversity in all guilds was mainly explained by turnover rather than nestedness, and the turnover was the highest for the motile and low-profile guilds. A more heterogeneous community was observed in Ascotán, showing that the mechanisms of diversity maintenance, such as dispersion abilities, were salt flat dependent. This suggests that the highest diversity could be related to human use, which challenges us to reexamine the effectiveness of past conservation activities in the area and to develop future strategies including both connected basins.

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The Unique Altiplano-Puna Plateau: Environmental Perspectives

Tapia

Murray

Ormachea-Muñoz

et al. 2022

Journal of South American Earth Sciences

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Ascotán and Carcote salt flats as sensors of humidity fluctuations and anthropic impacts in the transition zone of the Andean Altiplano

Cited by 9 publications

References 52 publications

Limnological response from high-altitude wetlands to the water supply in the Andean Altiplano

Limnological response from high-altitude wetlands to the water supply in the Andean Altiplano

Differentiation of Diatom Guilds in Extreme Environments in the Andean Altiplano

The Unique Altiplano-Puna Plateau: Environmental Perspectives

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