High-altitude varve records of abrupt environmental changes and mining activity over the last 4000 years in the Western French Alps (Lake Bramant, Grandes Rousses Massif)

2007 ◽  
Vol 26 (19-21) ◽  
pp. 2644-2660 ◽  
Author(s):  
Hervé Guyard ◽  
Emmanuel Chapron ◽  
Guillaume St-Onge ◽  
Flavio S. Anselmetti ◽  
Fabien Arnaud ◽  
...  
Keyword(s):  
High Altitude ◽  
Environmental Changes ◽  
Mining Activity ◽  
French Alps

scholarly journals A high-altitude peatland record of environmental changes in the NW Argentine Andes (24 ° S) over the last 2100 years

2016 ◽  
Vol 12 (5) ◽  
pp. 1165-1180 ◽  
Author(s):  
Karsten Schittek ◽  
Sebastian T. Kock ◽  
Andreas Lücke ◽  
Jonathan Hense ◽  
Christian Ohlendorf ◽  
...  
Keyword(s):  
High Altitude ◽  
Environmental Changes ◽  
Regional Scale ◽  
Central Andes ◽  
High Accumulation ◽  
Climate Conditions ◽  
Climate Anomalies ◽  
Dry Conditions ◽  
Induced Changes ◽  
The 19Th Century

Abstract. High-altitude cushion peatlands are versatile archives for high-resolution palaeoenvironmental studies, due to their high accumulation rates, range of proxies, and sensitivity to climatic and/or human-induced changes. Especially within the Central Andes, the knowledge about climate conditions during the Holocene is limited. In this study, we present the environmental and climatic history for the last 2100 years of Cerro Tuzgle peatland (CTP), located in the dry Puna of NW Argentina, based on a multi-proxy approach. X-ray fluorescence (XRF), stable isotope and element content analyses (δ13C, δ15N, TN and TOC) were conducted to analyse the inorganic geochemistry throughout the sequence, revealing changes in the peatlands' past redox conditions. Pollen assemblages give an insight into substantial environmental changes on a regional scale. The palaeoclimate varied significantly during the last 2100 years. The results reflect prominent late Holocene climate anomalies and provide evidence that in situ moisture changes were coupled to the migration of the Intertropical Convergence Zone (ITCZ). A period of sustained dry conditions prevailed from around 150 BC to around AD 150. A more humid phase dominated between AD 200 and AD 550. Afterwards, the climate was characterised by changes between drier and wetter conditions, with droughts at around AD 650–800 and AD  1000–1100. Volcanic forcing at the beginning of the 19th century (1815 Tambora eruption) seems to have had an impact on climatic settings in the Central Andes. In the past, the peatland recovered from climatic perturbations. Today, CTP is heavily degraded by human interventions, and the peat deposit is becoming increasingly susceptible to erosion and incision.

Mobility in the Mountains: Late Third and Second Millennia Alpine Societies' Engagements with the High-Altitude Zones in the Southern French Alps

2011 ◽  
Vol 14 (1-2) ◽  
pp. 88-115 ◽  
Author(s):  
Kevin Walsh ◽  
Florence Mocci
Keyword(s):  
High Altitude ◽  
Fundamental Change ◽  
Homo Economicus ◽  
Long Distance ◽  
French Alps ◽  
The Third ◽  
Economic Practices ◽  
Art Forms ◽  
Burial Rites ◽  
Alpine Space

The assessment of the important changes that occurred in late third and second millennia societies across Europe often emphasizes changes in technology and the emergence of associated objects and art forms, changes in burial rites, and developments in economic practices. Notions relating to the evolution of homo economicus dominate many of the discourses, and the evidence for increased long-distance trade / contact across Europe is used to bolster this assessment. These themes are underpinned by an obsession with ever-refined chrono-typological phases. In an attempt to present a more socially embedded perspective, this paper considers the changes that occurred in the uses of the high-altitude, sub-alpine, and alpine zones in the southern French Alps during the third and second millennia BC. From c. 2500 BC onwards, there was a fundamental change in the use of and engagement with this landscape. The first substantial stone-built pastoral structures at high altitude (2000 m and above), appear at this time. This departure in the use and structuring of the alpine space would have included concomitant changes in the nature of mobility, notions of territory, and memories associated with this area.

scholarly journals High Resolution Chemistry Transport Modeling with the On-Line CHIMERE-WRF Model over the French Alps—Analysis of a Feedback of Surface Particulate Matter Concentrations on Mountain Meteorology

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 565 ◽  
Author(s):  
Bertrand Bessagnet ◽  
Laurent Menut ◽  
Rémy Lapere ◽  
Florian Couvidat ◽  
Jean-Luc Jaffrezo ◽  
...  
Keyword(s):  
Air Pollution ◽  
Particulate Matter ◽  
Air Quality ◽  
High Altitude ◽  
Wrf Model ◽  
Synoptic Situation ◽  
Modeling Tools ◽  
Meteorological Model ◽  
French Alps ◽  
On Line

Air pollution is of major concern throughout the world and the use of modeling tools to analyze and forecast the pollutant concentrations in complex orographic areas remains challenging. This work proposes an exhaustive framework to analyze the ability of models to simulate the air quality over the French Alps up to 1.2 km resolution over Grenoble and the Arve Valley. The on-line coupled suite of models CHIMERE-WRF is used in its recent version to analyze a 1 month episode in November–December 2013. As expected, an improved resolution increases the concentrations close to the emission areas and reduced the negative bias for Particulate Matter that is the usual weakness of air quality models. However, the nitrate concentrations seem overestimated with at the same time an overestimation of surface temperature in the morning by WRF. Different WRF settings found in the literature are tested to improve the results, particularly the ability of the meteorological model to simulate the strong thermal inversions in the morning. Wood burning is one of the main contributor of air pollution during the period ranging from 80 to 90% of the Organic Matter. The activation of the on-line coupling has a moderate impact on the background concentrations but surprisingly a change of Particulate Matter (PM) concentrations in the valley will affect more the meteorology nearby high altitude areas than in the valley. This phenomenon is the result of a chain of processes involving the radiative effects and the water vapor column gradients in complex orographic areas. At last, the model confirms that the surrounding glaciers are largely impacted by long range transport of desert dust. However, in wintertime some outbreaks of anthropogenic pollution from the valley when the synoptic situation changes can be advected up to the nearby high altitude areas, then deposited.

scholarly journals Hydrogeochemsitry of montane springs and their influence on streams in the Cairngorm mountains, Scotland

1999 ◽  
Vol 3 (3) ◽  
pp. 409-419 ◽  
Author(s):  
C. Soulsby ◽  
R. Malcolm ◽  
R. Helliwell ◽  
R.C. Ferrier
Keyword(s):  
High Altitude ◽  
Surface Waters ◽  
Environmental Changes ◽  
Seasonal Pattern ◽  
Ionic Composition ◽  
Spring Water ◽  
Residence Times ◽  
Sea Salts ◽  
Fractured Bedrock ◽  
Catchment Areas

Abstract. Springs are important groundwater discharge points on the high altitude (>800m) plateaux of the Cairngorm mountains, Scotland and form important wetland habitats within what is often a dry, sub-arctic landscape. The hydrogeochemistry of a typical spring in the Allt a'Mharcaidh catchment was examined between 1995-98 in order to characterise its chemical composition, identify the dominant controls on its chemical evolution and estimate groundwater residence time using 18O isotopes. Spring water, sustained by groundwater flow in shallow drift deposits and fractured bedrock, was moderately acidic (mean pH 5.89), with a very low alkalinity (mean 18 μeq l-1) and the ionic composition was dominated by sea-salts derived from atmospheric sources. Geochemical modelling using NETPATH, predicted that the dissolution of plagioclase mainly controls the release of Si, non-marine Na, Ca, K and Al into spring water. Hydrological conditions influenced seasonal variations in spring chemistry, with snowmelt associated with more rapid groundwater flows and lower weathering rates than summer discharges. Downstream of the spring, the chemistry of surface water was fundamentally different as a result of drainage from larger catchment areas, with increased soil and drift cover, and higher evaporation rates. Thus, the hydrogeochemical influence of springs on surface waters appears to be localized. Mean δ18O values in spring water were lower and more damped than those in precipitation. Nevertheless, a sinusoidal seasonal pattern was observed and used to estimate mean residence times of groundwater of around 2 years. Thus, in the high altitude plateau of the Cairngorms, shallow, coarse drift deposits from significant aquifers. At lower altitudes, deeper drift deposits, combined with larger catchment areas, increase mean groundwater residence times to >5 years. At high altitudes, the shallow, permeable nature of the drifts dictates that groundwater is vulnerable to impacts of environmental changes that could be usefully monitored at spring sites.

Total mercury and methylmercury in high altitude surface snow from the French Alps

2011 ◽  
Vol 409 (19) ◽  
pp. 3949-3954 ◽  
Author(s):  
Nicolas Marusczak ◽  
Catherine Larose ◽  
Aurélien Dommergue ◽  
Emmanuel Yumvihoze ◽  
David Lean ◽  
...  
Keyword(s):  
High Altitude ◽  
Total Mercury ◽  
French Alps ◽  
Surface Snow

scholarly journals Altitudinal Zonation of Green Algae Biodiversity in the French Alps

2021 ◽  
Vol 12 ◽  
Author(s):  
Adeline Stewart ◽  
Delphine Rioux ◽  
Fréderic Boyer ◽  
Ludovic Gielly ◽  
François Pompanon ◽  
...  
Keyword(s):  
Green Algae ◽  
Environmental Changes ◽  
Natural Habitat ◽  
High Elevation ◽  
Altitudinal Zonation ◽  
French Alps ◽  
Eukaryotic Diversity ◽  
Mountain Environments ◽  
Strong Correlate ◽  
The Alps

Mountain environments are marked by an altitudinal zonation of habitat types. They are home to a multitude of terrestrial green algae, who have to cope with abiotic conditions specific to high elevation, e.g., high UV irradiance, alternating desiccation, rain and snow precipitations, extreme diurnal variations in temperature and chronic scarceness of nutrients. Even though photosynthetic green algae are primary producers colonizing open areas and potential markers of climate change, their overall biodiversity in the Alps has been poorly studied so far, in particular in soil, where algae have been shown to be key components of microbial communities. Here, we investigated whether the spatial distribution of green algae followed the altitudinal zonation of the Alps, based on the assumption that algae settle in their preferred habitats under the pressure of parameters correlated with elevation. We did so by focusing on selected representative elevational gradients at distant locations in the French Alps, where soil samples were collected at different depths. Soil was considered as either a potential natural habitat or temporary reservoir of algae. We showed that algal DNA represented a relatively low proportion of the overall eukaryotic diversity as measured by a universal Eukaryote marker. We designed two novel green algae metabarcoding markers to amplify the Chlorophyta phylum and its Chlorophyceae class, respectively. Using our newly developed markers, we showed that elevation was a strong correlate of species and genus level distribution. Altitudinal zonation was thus determined for about fifty species, with proposed accessions in reference databases. In particular, Planophila laetevirens and Bracteococcus ruber related species as well as the snow alga Sanguina genus were only found in soil starting at 2,000 m above sea level. Analysis of environmental and bioclimatic factors highlighted the importance of pH and nitrogen/carbon ratios in the vertical distribution in soil. Capacity to grow heterotrophically may determine the Trebouxiophyceae over Chlorophyceae ratio. The intensity of freezing events (freezing degree days), proved also determinant in Chlorophyceae distribution. Guidelines are discussed for future, more robust and precise analyses of environmental algal DNA in mountain ecosystems and address green algae species distribution and dynamics in response to environmental changes.

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