| 2. |
- van Gestel, Natasja C., et al.
(författare)
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Comparing temperature sensitivity of bacterial growth in Antarctic marine water and soil
- 2020
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26:4, s. 2280-2291
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Tidskriftsartikel (refereegranskat)abstract
- The western Antarctic Peninsula is an extreme low temperature environment that is warming rapidly due to global change. Little is known, however, on the temperature sensitivity of growth of microbial communities in Antarctic soils and in the surrounding oceanic waters. This is the first study that directly compares temperature adaptation of adjacent marine and terrestrial bacteria in a polar environment. The bacterial communities in the ocean were adapted to lower temperatures than those from nearby soil, with cardinal temperatures for growth in the ocean being the lowest so far reported for microbial communities. This was reflected in lower minimum (Tmin) and optimum temperatures (Topt) for growth in water (−17 and +20°C, respectively) than in soil (−11 and +27°C), with lower sensitivity to changes in temperature (Q10; 0–10°C interval) in Antarctic water (2.7) than in soil (3.9). This is likely due to the more stable low temperature conditions of Antarctic waters than soils, and the fact that maximum in situ temperatures in water are lower than in soils, at least in summer. Importantly, the thermally stable environment of Antarctic marine water makes it feasible to create a single temperature response curve for bacterial communities. This would thus allow for calculations of temperature-corrected growth rates, and thereby quantifying the influence of factors other than temperature on observed growth rates, as well as predicting the effects of future temperature increases on Antarctic marine bacteria.
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| 3. |
- van Gestel, Natasja C., et al.
(författare)
-
Temperature sensitivity of bacterial growth in a hot desert soil with large temperature fluctuations
- 2013
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Ingår i: Soil Biology & Biochemistry. - : Elsevier BV. - 0038-0717. ; 65, s. 180-185
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Tidskriftsartikel (refereegranskat)abstract
- Hot desert ecosystems are characterized by high soil temperatures with large fluctuations annually and diurnally. Thus, one could hypothesize that not only the microbial community would be adapted to high temperatures, but also have a large temperature range conducive for growth. We determined the temperature sensitivity of the soil bacterial community from the Chihuahuan Desert, Big Bend National Park, Texas, USA, using leucine incorporation as a proxy for bacterial growth. Soil samples were taken during early spring and mid-summer from the surface (0-5 cm) and deeper (15-20 cm) soil layers. Mean winter soil temperature preceding the spring samples was 15 degrees C and in summer 36 degrees C at both depths, but with larger amplitude in the top soil than deeper down. T-min was significantly lower in the top 0-5 cm than at 15-20 cm, -1.2 and 0.0 degrees C, respectively. T-opt also was higher in the top soil than deeper down, 42.9 and 41.4 degrees C, respectively, resulting in a larger temperature range for growth (T-opt - T-min) in the top soil reflecting the larger temperature fluctuations in this layer. There were no significant differences in cardinal temperatures for bacterial growth in soils sampled in early spring and mid-summer despite large seasonal differences in temperatures, showing that long periods of colder temperatures was less important than periods of high temperatures as selection pressure for temperature sensitivity. Comparing with earlier results from Antarctic soils (Rinnan et al., 2009), which in contrast represent an extremely low temperature environment, we suggest that the range of temperature cardinal temperatures for soil bacterial communities globally varies from around -15 to 0 degrees C for T-min and 25 to 45 degrees C for T-opt. (C) 2013 Elsevier Ltd. All rights reserved.
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