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| Titel |
Temperature characteristics of bacterial sulfate reduction in continental shelf and slope sediments |
| VerfasserIn |
J. E. Sawicka, B. B. Jørgensen, V. Brüchert |
| 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 ; 9, no. 8 ; Nr. 9, no. 8 (2012-08-30), S.3425-3435 |
| Datensatznummer |
250007255
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| Publikation (Nr.) |
 copernicus.org/bg-9-3425-2012.pdf |
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| Zusammenfassung |
| The temperature responses of sulfate-reducing microbial communities were used
as community temperature characteristics for their in situ temperature
adaptation, their origin, and dispersal in the deep sea. Sediments were
collected from a suite of coastal, continental shelf, and slope sediments
from the southwest and southeast Atlantic and permanently cold Arctic fjords
from water depths ranging from the intertidal zone to 4327 m. In situ
temperatures ranged from 8 °C on the shelf to −1 °C in the Arctic. Temperature
characteristics of the active sulfate-reducing community were determined in
short-term incubations with 35S-sulfate in a temperature gradient block
spanning a temperature range from 0 to 40 °C. An optimum temperature
(Topt) between 27 °C and 30 °C for the South
Atlantic shelf sediments and for the intertidal flat sediment from Svalbard
was indicative of a psychrotolerant/mesophilic sulfate-reducing community,
whereas Topt ≤20 °C in South Atlantic slope and Arctic
shelf sediments suggested a predominantly psychrophilic community. High
sulfate reduction rates (20–50%) at in situ temperatures compared to
those at Topt further support this interpretation and point to
the importance of the ambient temperature regime for regulating the
short-term temperature response of sulfate-reducing communities. A number of
cold (<4 °C) continental slope sediments showed broad temperature
optima reaching as high as 30 °C, suggesting the additional presence
of apparently mesophilic sulfate-reducing bacteria. Since the temperature
characteristics of these mesophiles do not fit with the permanently cold
deep-sea environment, we suggest that these mesophilic microorganisms are of
allochthonous origin and transported to this site. It is likely that they
were deposited along with the mass-flow movement of warmer shelf-derived
sediment. These data therefore suggest that temperature response profiles of
bacterial carbon mineralization processes can be used as community
temperature characteristics, and that mixing of bacterial communities
originating from diverse locations carrying different temperature
characteristics needs to be taken into account to explain temperature
response profiles of bacterial carbon mineralization processes in sediments. |
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