## Excess air in groundwater as a potential indicator of past environmental changes

2002
##### Authors
Aeschbach-Hertig, Werner
Beyerle, Urs
Holocher, Johannes
Kipfer, Rolf
##### Publication type
Contribution to a conference collection
##### Published in
Study of environmental change using isotope techniques : proceedings ; international conference held in Vienna, 23 - 27 April 2001 / International Atomic Energy Agency (ed.). - Vienna, 2002. - (C&S papers series, International Atomic Energy Agency ; 13,P). - pp. 174-183. - ISBN 92-0-116402-5
##### Abstract
Dissolved noble gases in groundwater are used to reconstruct paleotemperature, but also yield information about "excess air", a component of dissolved gases in excess of solubility equilibrium, derived from dissolution of trapped air in the ground. A good characterization of the excess air component is necessary not only to obtain reliable noble gas temperatures, but also to investigate the potential of excess air as a proxy for past environmental conditions. Two excess air related quantities can be derived from groundwater noble gas data sets: The initial air/water ratio and the pressure exerted on the entrapped air. Under recharge conditions typical for many aquifers, the excess of dissolved gases, expressed by the relative Ne excess ¨Ne, is mainly determined by the hydrostatic pressure on the entrapped air. Thus, we suggest that ¨Ne is essentially a measure of the amplitude of water table fluctuations in the recharge area. Comparing data sets from three aquifers in temperate, humid latitudes and three aquifers in tropical, semi-arid regions, we find that ¨Ne is generally higher in the tropical aquifers, possibly related to larger water table fluctuations in these aquifers characterized by deep unsaturated zones. Whereas ¨Ne shows little temporal variation in the mid-latitude aquifers, there is a strong signal of higher ¨Ne in the paleowaters of the tropical aquifers as compared to water recharged under modern climate conditions. This finding may indicate a higher variability of recharge in the past at the studied tropical sites.
##### Subject (DDC)
570 Biosciences, Biology
##### Conference
Study of environmental change using isotope techniques, Apr 23, 2001 - Apr 27, 2001, Vienna
##### Cite This
ISO 690AESCHBACH-HERTIG, Werner, Urs BEYERLE, Johannes HOLOCHER, Frank PEETERS, Rolf KIPFER, 2002. Excess air in groundwater as a potential indicator of past environmental changes. Study of environmental change using isotope techniques. Vienna, Apr 23, 2001 - Apr 27, 2001. In: INTERNATIONAL ATOMIC ENERGY AGENCY, , ed.. Study of environmental change using isotope techniques : proceedings ; international conference held in Vienna, 23 - 27 April 2001. Vienna, pp. 174-183. ISBN 92-0-116402-5
BibTex
@inproceedings{AeschbachHertig2002Exces-24396,
year={2002},
title={Excess air in groundwater as a potential indicator of past environmental changes},
number={13,P},
isbn={92-0-116402-5},
series={C&S papers series, International Atomic Energy Agency},
booktitle={Study of environmental change using isotope techniques : proceedings ; international conference held in Vienna, 23 - 27 April 2001},
pages={174--183},
editor={International Atomic Energy Agency},
author={Aeschbach-Hertig, Werner and Beyerle, Urs and Holocher, Johannes and Peeters, Frank and Kipfer, Rolf}
}

RDF
<rdf:RDF
xmlns:dcterms="http://purl.org/dc/terms/"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:bibo="http://purl.org/ontology/bibo/"
xmlns:dspace="http://digital-repositories.org/ontologies/dspace/0.1.0#"
xmlns:foaf="http://xmlns.com/foaf/0.1/"
xmlns:void="http://rdfs.org/ns/void#"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#" >
<dc:creator>Holocher, Johannes</dc:creator>
<void:sparqlEndpoint rdf:resource="http://localhost/fuseki/dspace/sparql"/>
<dcterms:issued>2002</dcterms:issued>
<dc:creator>Beyerle, Urs</dc:creator>
<bibo:uri rdf:resource="http://kops.uni-konstanz.de/handle/123456789/24396"/>
<dc:creator>Aeschbach-Hertig, Werner</dc:creator>
<dc:contributor>Aeschbach-Hertig, Werner</dc:contributor>
<dc:contributor>Peeters, Frank</dc:contributor>
<dcterms:bibliographicCitation>Dissolved noble gases in groundwater are used to reconstruct paleotemperature, but also yield information about 'excess air', a component of dissolved gases in excess of solubility equilibrium, derived from dissolution of trapped air in the ground. A good characterization of the excess air component is necessary not only to obtain reliable noble gas temperatures, but also to investigate the potential of excess air as a proxy for past environmental conditions. Two excess air related quantities can be derived from groundwater noble gas data sets: The initial air/water ratio and the pressure exerted on the entrapped air. Under recharge conditions typical for many aquifers, the excess of dissolved gases, expressed by the relative Ne excess ΔNe, is mainly determined by the hydrostatic pressure on the entrapped air. Thus, we suggest that ΔNe is essentially a measure of the amplitude of water table fluctuations in the recharge area. Comparing data sets from three aquifers in temperate, humid latitudes and three aquifers in tropical, semi-arid regions, we find that ΔNe is generally higher in the tropical aquifers, possibly related to larger water table fluctuations in these aquifers characterized by deep unsaturated zones. Whereas ΔNe shows little temporal variation in the mid-latitude aquifers, there is a strong signal of higher ΔNe in the paleowaters of the tropical aquifers as compared to water recharged under modern climate conditions. This finding may indicate a higher variability of recharge in the past at the studied tropical sites.</dcterms:bibliographicCitation>
<dcterms:abstract xml:lang="eng">Dissolved noble gases in groundwater are used to reconstruct paleotemperature, but also&#xD;
yield information about "excess air", a component of dissolved gases in excess of solubility&#xD;
equilibrium, derived from dissolution of trapped air in the ground. A good characterization of the&#xD;
excess air component is necessary not only to obtain reliable noble gas temperatures, but also to&#xD;
investigate the potential of excess air as a proxy for past environmental conditions. Two excess air&#xD;
related quantities can be derived from groundwater noble gas data sets: The initial air/water ratio and&#xD;
the pressure exerted on the entrapped air. Under recharge conditions typical for many aquifers, the&#xD;
excess of dissolved gases, expressed by the relative Ne excess ¨Ne, is mainly determined by the&#xD;
hydrostatic pressure on the entrapped air. Thus, we suggest that ¨Ne is essentially a measure of the&#xD;
amplitude of water table fluctuations in the recharge area. Comparing data sets from three aquifers in&#xD;
temperate, humid latitudes and three aquifers in tropical, semi-arid regions, we find that ¨Ne is&#xD;
generally higher in the tropical aquifers, possibly related to larger water table fluctuations in these&#xD;
aquifers characterized by deep unsaturated zones. Whereas ¨Ne shows little temporal variation in the&#xD;
mid-latitude aquifers, there is a strong signal of higher ¨Ne in the paleowaters of the tropical aquifers&#xD;
as compared to water recharged under modern climate conditions. This finding may indicate a higher&#xD;
variability of recharge in the past at the studied tropical sites.</dcterms:abstract>
<dcterms:isPartOf rdf:resource="https://kops.uni-konstanz.de/server/rdf/resource/123456789/28"/>
<dc:creator>Kipfer, Rolf</dc:creator>
<dc:contributor>Holocher, Johannes</dc:contributor>
<dc:language>eng</dc:language>
<foaf:homepage rdf:resource="http://localhost:8080/"/>
<dspace:isPartOfCollection rdf:resource="https://kops.uni-konstanz.de/server/rdf/resource/123456789/28"/>
<dcterms:hasPart rdf:resource="https://kops.uni-konstanz.de/bitstream/123456789/24396/2/Aeschbach_243968.pdf"/>
<dc:contributor>Kipfer, Rolf</dc:contributor>
<dc:contributor>Beyerle, Urs</dc:contributor>
<dc:date rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2013-09-19T09:09:06Z</dc:date>
<dc:rights>terms-of-use</dc:rights>
<dspace:hasBitstream rdf:resource="https://kops.uni-konstanz.de/bitstream/123456789/24396/2/Aeschbach_243968.pdf"/>
<dc:creator>Peeters, Frank</dc:creator>
<dcterms:title>Excess air in groundwater as a potential indicator of past environmental changes</dcterms:title>
<dcterms:rights rdf:resource="https://rightsstatements.org/page/InC/1.0/"/>
<dcterms:available rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2013-09-19T09:09:06Z</dcterms:available>
</rdf:Description>
</rdf:RDF>

No