scholarly journals DO RADIOCARBON AGES OF PLANT WAX BIOMARKERS AGREE WITH 14C-TOC/OSL-BASED AGE MODELS IN AN ARID HIGH-ALTITUDE LAKE SYSTEM?

Radiocarbon ◽  
2021 ◽  
pp. 1-16
Author(s):  
Bernhard Aichner ◽  
Merle Gierga ◽  
Alexander Stolz ◽  
Monika Mętrak ◽  
Mateusz Wilk ◽  
...  
Keyword(s):  
High Altitude ◽  
Sediment Core ◽  
Turnover Time ◽  
Lake System ◽  
Leaf Wax ◽  
Leaf Waxes ◽  
Age Model ◽  
High Altitude Lake ◽  
Age Range ◽  
Plant Wax

ABSTRACT To elucidate the dynamics of terrestrial leaf waxes in a high-altitude lake system, we performed compound-specific radiocarbon analysis (CSRA) of long-chain n-alkanes in two sediment core sections from Lake Karakul (Pamirs, Tajikistan) and in surface soil samples from the catchment area. We aimed to answer the question whether the n-alkanes are delivered into the lake sediment with substantial delay due to storage in soils, which may cause a potential bias when used as paleoenvironmental proxies. In the surface soils, the CSRA results reveal an age range of n-alkanes from modern to 2278 ± 155 cal BP. In the two sediment core samples, three of the four n-alkane ages fell on the lower ends of the 1σ-uncertainty ranges of modeled ages of the sediments (based on AMS 14C-TOC and OSL dating results). We conclude that sedimentary leaf waxes represent compounds with intermediate turnover time in soils, for example originating from alluvial plains close to the shores. Overall, the results provide evidence that sedimentary leaf wax compounds in this cold and arid setting are potentially older than the conventional age model indicates, but these findings need to be interpreted in context of the generally large uncertainty ranges of such age models.

Compound-specific radiocarbon ages of soil and sedimentary leaf wax biomarkers in an arid high-altitude environment

2021 ◽  
Author(s):  
Bernhard Aichner ◽  
Janet Rethemeyer ◽  
Merle Gierga ◽  
Alexander Stolz ◽  
Monika Mętrak ◽  
...  
Keyword(s):  
High Altitude ◽  
Sediment Core ◽  
Lacustrine Sediments ◽  
Turnover Time ◽  
Soil Samples ◽  
Transport Dynamics ◽  
Leaf Wax ◽  
Leaf Waxes ◽  
Age Model ◽  
High Altitude Lake

<p>Compound-specific radiocarbon analysis (CSRA) of leaf waxes has revealed significant lag times before compounds are deposited in marine and lacustrine sediments. No such data so far exist for a cold and arid high altitude lake system, where carbon turnover and biomarker fluxes to sediments are expected to be relatively low. To elucidate transport dynamics of terrestrial leaf waxes in such an environment (MAT: -4°C, MAP <100mm), we determined CSRA-ages of selected long-chain <em>n</em>-alkanes in surface soil samples (0-10 cm), collected from alpine meadows in the catchment of Lake Karakul (Pamirs, Tajikistan), and in two sections  of a well dated sediment core from the same lake. We aimed to answer the question if there is a potential bias in the interpretation of biomarker records, in case the leaf wax compounds are significantly older than the sediment age-model suggests.</p><p><em>n</em>C<sub>29</sub>- and <em>n</em>C<sub>31</sub>-alkanes in the soil samples exhibited variable ages, ranging from 105±79 to 2260±155 cal. yrs BP. In the two sediment core samples, three of the four obtained ages for <em>n</em>C<sub>29</sub> and <em>n</em>C<sub>31</sub> felt on the very lower ends of the 1ϭ-uncertainty ranges of modelled ages (based on AMS <sup>14</sup>C<sub>TOC</sub> and OSL dating results).</p><p>The large span of CSRA-ages of soils gives evidence for heterogeneous decomposition and transport conditions in the lake catchment. We hypothesize that compounds with longest pre-aging contributed in lower proportions to the accumulated lake sediments and further suggest that sedimentary leaf waxes represent compounds with intermediate turnover time in soils, for example originating from alluvial plains close to the shores. Overall, the obtained results give evidence that sedimentary leaf wax compounds in this cold and arid high altitude setting are potentially older than the conventional age-model indicates. On the other hand, these findings need to be interpreted in context of the generally large uncertainty ranges of such age-models, which are further influenced by unknown factors for example changes of reservoir effects. </p>

Depth Profile Of Trace Elements In a Sediment Core Of a High-Altitude Lake Deposit At The Pyrenees, Spain

2006 ◽  
Vol 172 (1-4) ◽  
pp. 273-293 ◽  
Author(s):  
Isela Lavilla ◽  
A. V. Filgueiras ◽  
F. Valverde ◽  
J. Millos ◽  
A. Palanca ◽  
...  
Keyword(s):  
Trace Elements ◽  
High Altitude ◽  
Sediment Core ◽  
Depth Profile ◽  
High Altitude Lake

scholarly journals Evidence for centennial-scale Mid-Holocene episodes of hypolimnetic anoxia in a high-altitude lake system from central Tian Shan (Kyrgyzstan)

2021 ◽  
Vol 252 ◽  
pp. 106748
Author(s):  
Philippe Sorrel ◽  
Kévin Jacq ◽  
Antonin Van Exem ◽  
Gilles Escarguel ◽  
Benjamin Dietre ◽  
...  
Keyword(s):  
High Altitude ◽  
Lake System ◽  
High Altitude Lake ◽  
Tian Shan

scholarly journals First record of Ceratium furcoides (Dinophyta), an invasive species, in a temporary high-altitude lake in the Iron Quadrangle (MG, Southeast Brazil)

2015 ◽  
Vol 75 (1) ◽  
pp. 98-103 ◽  
Author(s):  
RA. Moreira ◽  
O. Rocha ◽  
RM. Santos ◽  
R. Laudares-Silva ◽  
ES. Dias ◽  
...  
Keyword(s):  
Invasive Species ◽  
High Altitude ◽  
First Record ◽  
Mining District ◽  
Aquatic Communities ◽  
Rainy Period ◽  
Southeast Brazil ◽  
Iron Quadrangle ◽  
Global Connections ◽  
High Altitude Lake

Dinoflagellates of the genus Ceratium are generally marine organisms, but rare occurrences in freshwater have been observed in Brazil. In this paper we are recording for the first time the presence of Ceratium furcoides, an invasive species, in a shallow, natural intermittent pool formed at a high-altitude at the southern end of the Iron Quadrangle, an iron-mining district of Minas Gerais State (Southeast Brazil). Samples were collected in October and November of 2010 (rainy period). The population density of this organism observed in Lagoa Seca (“Dry Pool”) was very low, at most 4 ind L–1. Mountain lakes are extremely vulnerable to atmospheric deposition of organisms, making them valuable witnesses both of the many forms of impact arising from human activities and of the extended global connections that facilitate the dispersion and introduction of new species over great distances. Studies on the population dynamics of C. furcoides in natural tropical systems are still rare and very recent to the brazilian scenario and hence the monitoring of its dynamics and the potential impact on aquatic communities of its becoming established are essential to an understanding of the process of bioinvasion by this species.

Spatiotemporal change of water level in ungauged high-altitude tropical lakes: a DInSAR approach

2021 ◽  
Author(s):  
Sebastián Palomino-Ángel ◽  
Raúl F. Vázquez ◽  
Henrietta Hampel ◽  
Jesús A. Anaya-Acevedo ◽  
Pablo V. Mosquera ◽  
...  
Keyword(s):  
High Altitude ◽  
Water Level ◽  
Mountain Range ◽  
Similar Data ◽  
Water Level Change ◽  
Level Change ◽  
Water Level Changes ◽  
Basin Scale ◽  
High Altitude Lake ◽  
Lake Systems

<p>Spatiotemporal characteristics of physical responses of lakes to external and environmental changes are still largely unknown due to the consistent lack of monitoring of water level and corresponding changes in water storage in lakes. Understanding these changes is a fundamental step in advancing regional management of natural and anthropogenic systems that depend on the water resources of lakes. As an illustrative example, we here report a case study involving lakes of the headwater topical Andes mountain range, which, despite guaranteeing water security to millions of downstream inhabitants, still remain significantly ungauged. We present a novel evaluation of the potential of Differential Interferometric Synthetic Aperture Radar DInSAR techniques for the spatiotemporal analysis of patterns of water level change in lakes such as the ones comprising these ungauged high-altitude lake systems. Time series of Sentinel-1B data for the years 2017 and 2018 were used to generate continuous interferograms representing water level changes in twenty-four lakes of the Cajas National Park, Ecuador. The relation of these water level changes with climatic and topographical factors were analyzed to validate the methodology, and determine any patterns of change and response to climatic drivers. We found relatively high Pearson correlation coefficients between regional precipitation and water level change as estimated from the interferograms. Furthermore, we found an important negative relationship between water level change, as obtained from the DInSAR phase, and lake surface area. The study revealed a spatial trend of this correlation in terms of the altitude of the lakes at the basin scale; that is, lower correlation values were found in the headers of the basins, whilst higher correlation values were found at lower basin altitudes. The results of the present study demonstrate the potential of DInSAR techniques based on Sentinel-1 data for the monitoring of hydrologic changes in open water surfaces, and the possible validation of the DInSAR results with precipitation when gauged water level data is missing. These results are a basis to propose monitoring strategies in ungauged high-altitude lake systems in regions with similar data gauging constraints. Future work will encompass the integration of ongoing water level gauging for further validation of the herein depicted lake water level estimation approach.</p>

scholarly journals The influence of Eucalyptus plantations on the macrofauna associated with Salvinia auriculata in Southeast Brazil

2002 ◽  
Vol 62 (1) ◽  
pp. 63-68 ◽  
Author(s):  
M. CALLISTO ◽  
F. A. R. BARBOSA ◽  
P. MORENO
Keyword(s):  
High Altitude ◽  
Atlantic Forest ◽  
Littoral Zone ◽  
Macroinvertebrate Communities ◽  
Vegetation Types ◽  
Aquatic Fern ◽  
Eucalyptus Plantations ◽  
Major Controlling Factor ◽  
High Altitude Lake ◽  
Macroinvertebrate Fauna

The influence of Eucalyptus plantations on the structure and composition of macroinvertebrate communities associated with the aquatic fern Salvinia auriculata Aublet were investigated in a high altitude lake bordered by either secondary Atlantic forest or Eucalyptus plantations. Comparisons of the diversity of Chironomidae (Diptera, Insecta) larvae in the littoral zone between these two vegetation types showed higher diversity of larvae in waters bordered by Eucalyptus. The results demonstrated that the predominance of carnivorous taxa among the macroinvertebrate fauna appears to be the major controlling factor for limiting diversity in lake areas bordered by Eucalyptus.

Satellite-measured water properties in high altitude Lake Tahoe

2020 ◽  
Vol 178 ◽  
pp. 115839 ◽  
Author(s):  
Menghua Wang ◽  
Wei Shi ◽  
Shohei Watanabe
Keyword(s):  
High Altitude ◽  
Lake Tahoe ◽  
Water Properties ◽  
High Altitude Lake ◽  
Measured Water

scholarly journals Physicochemical Parameters Affecting the Distribution and Diversity of the Water Column Microbial Community in the High-Altitude Andean Lake System of La Brava and La Punta

2020 ◽  
Vol 8 (8) ◽  
pp. 1181
Author(s):  
Reynaldo Núñez Salazar ◽  
Carlos Aguirre ◽  
Jorge Soto ◽  
Pamela Salinas ◽  
Carlos Salinas ◽  
...  
Keyword(s):  
Microbial Community ◽  
High Altitude ◽  
Water Column ◽  
Physicochemical Parameters ◽  
Microbial Community Composition ◽  
Atacama Desert ◽  
Rrna Gene ◽  
16S Rrna Gene Analysis ◽  
Lake System ◽  
Influence Of Water

Due to the low incidence of precipitation attributed to climate change, many high-altitude Andean lakes (HAALs) and lagoons distributed along the central Andes in South America may soon disappear. This includes La Brava–La Punta, a brackish lake system located south of the Salar de Atacama within a hyper-arid and halophytic biome in the Atacama Desert. Variations in the physicochemical parameters of the water column can induce changes in microbial community composition, which we aimed to determine. Sixteen sampling points across La Brava–La Punta were studied to assess the influence of water physicochemical properties on the aquatic microbial community, determined via 16S rRNA gene analysis. Parameters such as pH and the concentrations of silica, magnesium, calcium, salinity, and dissolved oxygen showed a more homogenous pattern in La Punta samples, whereas those from La Brava had greater variability; pH and total silica were significantly different between La Brava and La Punta. The predominant phyla were Proteobacteria, Bacteroidetes, Actinobacteria, and Verrucomicrobia. The genera Psychroflexus (36.85%), Thiomicrospira (12.48%), and Pseudomonas (7.81%) were more abundant in La Brava, while Pseudospirillum (20.73%) and Roseovarius (17.20%) were more abundant in La Punta. Among the parameters, pH was the only statistically significant factor influencing the diversity within La Brava lake. These results complement the known microbial diversity and composition in the HAALs of the Atacama Desert.

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