 |
| Titel |
Temperature and moisture effects on ammonia oxidizer communities in cryoturbated Arctic soils |
| VerfasserIn |
Stefanie Aiglsdorfer, Ricardo J. E. Alves, Jiří Bárta, Iva Kohoutová, Hana Bošková, Kateřina Diáková, Petr Čapek, Jörg Schnecker, Birgit Wild, Maria Mooshammer, Tim Urich, Norman Gentsch, Antje Gittel, Georg Guggenberger, Robert Mikutta, Nikolay Lashchinskiy, Andreas Richter, Hana Šantrůčková, Olga Shibistova, Christa Schleper |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250099045
|
| Publikation (Nr.) |
 EGU/EGU2014-14788.pdf |
|
|
|
|
|
| Zusammenfassung |
| Arctic permafrost-affected soils contain large amounts of soil organic carbon (SOC) and are
expected to experience drastic changes in environmental conditions, such as moisture and
temperature, due to the high surface temperature increase predicted for these regions.
Although the SOC decomposition processes driven by the microbiota are considered to be
nitrogen (N) limited, little information about the microbial groups involved in N cycle is
currently available, including their reactions to environmental changes. Here, we investigate
the presence of ammonia oxidizing archaea (AOA) and bacteria (AOB) in distinct soil
horizons from the Taymyr peninsula (Siberia, Russia), and investigate their activities under
changing temperature and moisture regimes. These two groups of organisms perform the first
step in nitrification, an important and rate limiting process in the global N cycle, which
involves the oxidation of ammonia to nitrate via nitrite. The soil samples were separated into
different horizons: organic topsoil (O) and subducted organic topsoil (Ajj). The
samples were incubated for 18 weeks at 4, 12 and 20°C and 50, 80 and 100 %
water holding capacity (WHC). AOA and AOB abundances were quantified by
quantitative PCR targeting genes of the key metabolic enzyme, ammonia monooxygenase.
AOA diversity was analyzed in-depth by high-throughput amplicon sequencing of
the same gene. Additionally, gross and net nitrification and mineralization rates
were determined in order to investigate potential relationships between AOA and
AOB populations and these processes, in response to the incubation treatments. We
found higher abundances of AOA than AOB in the organic topsoil, whereas AOB
dominated in the subducted organic topsoil. Increased temperature resulted in higher
numbers of both groups at low WHC %, with AOB showing a more pronounced
response. However, these effects were not observed under anaerobic conditions (100 %
WHC). Deep sequencing of AOA amoA genes revealed the presence of functionally
heterogeneous AOA populations and complex changes in the population composition in
response to all treatments. Interestingly, the effect of different temperatures and
moisture on net nitrification throughout the incubation did not always correspond to the
effect observed on AOA and AOB abundance. This study provides insights into the
dynamics of nitrifier populations in Arctic soils, and suggests that they hold an
important role in the response of the N cycle in Arctic soils to environmental changes. |
|
|
|
|
|
|