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| Titel |
Microbial DNA; a possible tracer of groundwater |
| VerfasserIn |
Ayumi Sugiyama, Takuya Segawa, Tsuyumi Furuta, Kazuyo Nagaosa, Maki Tsujimura, Kenji Kato |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250142282
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| Publikation (Nr.) |
 EGU/EGU2017-5883.pdf |
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| Zusammenfassung |
| Though chemical analysis of groundwater shows an averaged value of chemistry of the
examined water which was blended by various water with different sources and routes in
subsurface environment, microbial DNA analysis may suggest the place where they
originated, which may give information of the source and transport routes of the water
examined.
A huge amount of groundwater is stored in lava layer with maximum depth of 300m in
Mt. Fuji (3,776m asl ), the largest volcanic mountain in Japan. Although the density of
prokaryotes was low in the examined groundwater of Mt. Fuji, thermophilic prokaryotes as
Thermoanaerobacterales, Gaiellales and Thermoplasmatales were significantly detected.
They are optimally adapted to the temperature higher than 40oC. This finding suggests that at
least some of the source of the examined groundwater was subsurface environment with
600m deep or greater, based on a temperature gradient of 4oC/100m and temperature
of spring water ranges from 10 to 15oC in the foot of Mt. Fuji. This depth is far
below the lava layer. Thus, the groundwater is not simply originated from the lava
layer.
In addition to those findings, we observed a very fast response of groundwater just
a couple of weeks after the heavy rainfall exceeding 2 or 300 mm/event in Mt.
Fuji. The fast response was suggested by a sharp increase in bacterial abundance
in spring water located at 700m in height in the west foot of Mt. Fuji, where the
average recharge elevation of groundwater was estimated to be 1,500m - 1,700m
(Kato et. al. EGU 2016). This increase was mainly provided by soil bacteria as
Burkholderiales, which might be detached from soil by strengthened subsurface
flow caused by heavy rainfall. This suggests that heavy rainfall promotes shallow
subsurface flow contributing to the discharge in addition to the groundwater in the deep
aquifer.
Microbial DNA, thus could give information about the route of the examined
groundwater, which was never elucidated by analysis of chemical materials dissolved in
groundwater. Though viral particle was employed as a tracer to chase the movement of
groundwater, it doesn’t tell the chemical and physical environmental condition where the
particle was incorporated into groundwater. Thus, we propose microbial DNA as a new tracer
to track the route of groundwater. |
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