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| Titel |
Permafrost coverage, watershed area and season control of dissolved carbon and major elements in western Siberian rivers |
| VerfasserIn |
O. S. Pokrovsky, R. M. Manasypov, S. Loiko, L. S. Shirokova, I. A. Krickov, B. G. Pokrovsky, L. G. Kolesnichenko, S. G. Kopysov, V. A. Zemtzov, S. P. Kulizhsky, S. N. Vorobyev, S. N. Kirpotin |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 21 ; Nr. 12, no. 21 (2015-11-05), S.6301-6320 |
| Datensatznummer |
250118152
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| Publikation (Nr.) |
 copernicus.org/bg-12-6301-2015.pdf |
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| Zusammenfassung |
| Analysis of organic and inorganic carbon (DOC and DIC, respectively), pH, Na,
K, Ca, Mg, Cl, SO4 and Si in ~ 100 large and small rivers
(< 10 to ≤ 150 000 km2) of western Siberia sampled
in winter, spring, and summer over a more than 1500 km latitudinal gradient
allowed establishing main environmental factors controlling the transport of
river dissolved components in this environmentally important region,
comprising continuous, discontinuous, sporadic and permafrost-free zones.
There was a significant latitudinal trend consisting in a general decrease in
DOC, DIC, SO4, and major cation (Ca, Mg, Na, K) concentration northward,
reflecting the interplay between groundwater feeding (detectable mostly in
the permafrost-free zone, south of 60° N) and surface flux (in the
permafrost-bearing zone). The northward decrease in concentration of
inorganic components was strongly pronounced both in winter and spring,
whereas for DOC, the trend of concentration decrease with latitude was absent
in winter, and less pronounced in spring flood than in summer baseflow. The
most significant decrease in K concentration from the southern
(< 59° N) to the northern (61–67° N) watersheds occurs
in spring, during intense plant litter leaching. The latitudinal trends
persisted for all river watershed size, from < 100 to
> 10 000 km2. Environmental factors are ranked by their increasing
effect on DOC, DIC, δ13CDIC, and major elements in
western Siberian rivers as follows: watershed area < season < latitude. Because the degree of the groundwater feeding is different
between large and small rivers, we hypothesize that, in addition to
groundwater feeding of the river, there was a significant role of surface and
shallow subsurface flow linked to plant litter degradation and peat leaching.
We suggest that plant-litter- and topsoil-derived DOC adsorbs on clay mineral
horizons in the southern, permafrost-free and discontinuous/sporadic
permafrost zone but lacks the interaction with minerals in the continuous
permafrost zone. It can be anticipated that, under climate warming in western
Siberia, the maximal change will occur in small (< 1000 km2
watershed) rivers DOC, DIC and ionic composition and this change will be
mostly pronounced in summer. |
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