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Modeling the habitat range of phototrophs in yellowstone national park: toward the development of a comprehensive fitness landscape.

Boyd ES, Fecteau KM, Havig JR, Shock EL, Peters JW - Front Microbiol (2012)

Bottom Line: Light-driven DIC uptake decreased systematically with increasing concentrations of sulfide in acidic, algal-dominated systems, but was unaffected in alkaline, cyanobacterial-dominated systems.In both alkaline and acidic systems, light-driven DIC uptake was suppressed in cultures incubated at temperatures 10°C greater than their in situ temperature.Collectively, these quantitative results indicate that apart from light availability, the habitat range of phototrophs in YNP springs is defined largely by constraints imposed firstly by temperature and secondly by sulfide on the activity of these populations that inhabit the edges of the habitat range.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Biochemistry, Astrobiology Biogeocatalysis Research Center, Montana State University Bozeman, MT, USA.

ABSTRACT
The extent to which geochemical variation shapes the distribution of phototrophic metabolisms was modeled based on 439 observations in geothermal springs in Yellowstone National Park (YNP), Wyoming. Generalized additive models (GAMs) were developed to predict the distribution of phototrophic metabolism as a function of spring temperature, pH, and total sulfide. GAMs comprised of temperature explained 38.8% of the variation in the distribution of phototrophic metabolism, whereas GAMs comprised of sulfide and pH explained 19.6 and 11.2% of the variation, respectively. These results suggest that of the measured variables, temperature is the primary constraint on the distribution of phototrophs in YNP. GAMs comprised of multiple variables explained a larger percentage of the variation in the distribution of phototrophic metabolism, indicating additive interactions among variables. A GAM that combined temperature and sulfide explained the greatest variation in the dataset (53.4%) while minimizing the introduction of degrees of freedom. In an effort to verify the extent to which phototroph distribution reflects constraints on activity, we examined the influence of sulfide and temperature on dissolved inorganic carbon (DIC) uptake rates under both light and dark conditions. Light-driven DIC uptake decreased systematically with increasing concentrations of sulfide in acidic, algal-dominated systems, but was unaffected in alkaline, cyanobacterial-dominated systems. In both alkaline and acidic systems, light-driven DIC uptake was suppressed in cultures incubated at temperatures 10°C greater than their in situ temperature. Collectively, these quantitative results indicate that apart from light availability, the habitat range of phototrophs in YNP springs is defined largely by constraints imposed firstly by temperature and secondly by sulfide on the activity of these populations that inhabit the edges of the habitat range. These findings are consistent with the predictions from GAMs and provide a quantitative framework from which to translate distributional patterns into fitness landscapes for use in interpreting the environmental constraints that have shaped the evolution of this process through Earth history.

No MeSH data available.


The photosynthetic fringe, or the transition from chemosynthetic to photosynthetic metabolism, as denoted by arrows, for Bijah Spring in March 2010 (A), Dragon Spring in March 2010 (B), Nymph Creek in March 2010 (C), and Perpetual Spouter in August of 2011 (D).
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Figure 3: The photosynthetic fringe, or the transition from chemosynthetic to photosynthetic metabolism, as denoted by arrows, for Bijah Spring in March 2010 (A), Dragon Spring in March 2010 (B), Nymph Creek in March 2010 (C), and Perpetual Spouter in August of 2011 (D).

Mentions: Prior to examining the influence of physical and chemical constraints on the activity of phototrophs in YNP, it was necessary to determine if the photosynthetic fringe (Figure 3) was the result of competition between phototrophs and chemotrophs for this niche, as this was previously suggested (Boyd et al., 2009b). Competition experiments were performed at the photosynthetic fringe in Nymph Creek (pH 2.99, 52.7°C), Dragon Spring (pH 2.95, 46.5°C), and Bijah Spring (pH 7.40, 70.0°C) in March of 2010. The phototrophic assemblages near the photosynthetic fringe at both Nymph Creek and Dragon Spring are both comprised of algae related to Cyanidioschyzon sp. (Ferris et al., 2005; Lehr et al., 2007; Boyd et al., 2009a), whereas the phototrophic assemblages near the photosynthetic fringe at Bijah Spring are dominated by Synechococcus sp. and Roseiflexus sp. (King et al., 2006). Populations comprising the chemosynthetic assemblages near the fringe in both Nymph Creek and Dragon Spring are thought to be comprised primarily of organisms affiliated with Hydrogenobacter sp., Desulfurella sp., and Acidimicrobium sp. (Jackson et al., 2001; Ferris et al., 2003), whereas populations associated with chemotrophic assemblages in Bijah Spring are most closely related to Thermotoga sp. (King et al., 2006).


Modeling the habitat range of phototrophs in yellowstone national park: toward the development of a comprehensive fitness landscape.

Boyd ES, Fecteau KM, Havig JR, Shock EL, Peters JW - Front Microbiol (2012)

The photosynthetic fringe, or the transition from chemosynthetic to photosynthetic metabolism, as denoted by arrows, for Bijah Spring in March 2010 (A), Dragon Spring in March 2010 (B), Nymph Creek in March 2010 (C), and Perpetual Spouter in August of 2011 (D).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376417&req=5

Figure 3: The photosynthetic fringe, or the transition from chemosynthetic to photosynthetic metabolism, as denoted by arrows, for Bijah Spring in March 2010 (A), Dragon Spring in March 2010 (B), Nymph Creek in March 2010 (C), and Perpetual Spouter in August of 2011 (D).
Mentions: Prior to examining the influence of physical and chemical constraints on the activity of phototrophs in YNP, it was necessary to determine if the photosynthetic fringe (Figure 3) was the result of competition between phototrophs and chemotrophs for this niche, as this was previously suggested (Boyd et al., 2009b). Competition experiments were performed at the photosynthetic fringe in Nymph Creek (pH 2.99, 52.7°C), Dragon Spring (pH 2.95, 46.5°C), and Bijah Spring (pH 7.40, 70.0°C) in March of 2010. The phototrophic assemblages near the photosynthetic fringe at both Nymph Creek and Dragon Spring are both comprised of algae related to Cyanidioschyzon sp. (Ferris et al., 2005; Lehr et al., 2007; Boyd et al., 2009a), whereas the phototrophic assemblages near the photosynthetic fringe at Bijah Spring are dominated by Synechococcus sp. and Roseiflexus sp. (King et al., 2006). Populations comprising the chemosynthetic assemblages near the fringe in both Nymph Creek and Dragon Spring are thought to be comprised primarily of organisms affiliated with Hydrogenobacter sp., Desulfurella sp., and Acidimicrobium sp. (Jackson et al., 2001; Ferris et al., 2003), whereas populations associated with chemotrophic assemblages in Bijah Spring are most closely related to Thermotoga sp. (King et al., 2006).

Bottom Line: Light-driven DIC uptake decreased systematically with increasing concentrations of sulfide in acidic, algal-dominated systems, but was unaffected in alkaline, cyanobacterial-dominated systems.In both alkaline and acidic systems, light-driven DIC uptake was suppressed in cultures incubated at temperatures 10°C greater than their in situ temperature.Collectively, these quantitative results indicate that apart from light availability, the habitat range of phototrophs in YNP springs is defined largely by constraints imposed firstly by temperature and secondly by sulfide on the activity of these populations that inhabit the edges of the habitat range.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Biochemistry, Astrobiology Biogeocatalysis Research Center, Montana State University Bozeman, MT, USA.

ABSTRACT
The extent to which geochemical variation shapes the distribution of phototrophic metabolisms was modeled based on 439 observations in geothermal springs in Yellowstone National Park (YNP), Wyoming. Generalized additive models (GAMs) were developed to predict the distribution of phototrophic metabolism as a function of spring temperature, pH, and total sulfide. GAMs comprised of temperature explained 38.8% of the variation in the distribution of phototrophic metabolism, whereas GAMs comprised of sulfide and pH explained 19.6 and 11.2% of the variation, respectively. These results suggest that of the measured variables, temperature is the primary constraint on the distribution of phototrophs in YNP. GAMs comprised of multiple variables explained a larger percentage of the variation in the distribution of phototrophic metabolism, indicating additive interactions among variables. A GAM that combined temperature and sulfide explained the greatest variation in the dataset (53.4%) while minimizing the introduction of degrees of freedom. In an effort to verify the extent to which phototroph distribution reflects constraints on activity, we examined the influence of sulfide and temperature on dissolved inorganic carbon (DIC) uptake rates under both light and dark conditions. Light-driven DIC uptake decreased systematically with increasing concentrations of sulfide in acidic, algal-dominated systems, but was unaffected in alkaline, cyanobacterial-dominated systems. In both alkaline and acidic systems, light-driven DIC uptake was suppressed in cultures incubated at temperatures 10°C greater than their in situ temperature. Collectively, these quantitative results indicate that apart from light availability, the habitat range of phototrophs in YNP springs is defined largely by constraints imposed firstly by temperature and secondly by sulfide on the activity of these populations that inhabit the edges of the habitat range. These findings are consistent with the predictions from GAMs and provide a quantitative framework from which to translate distributional patterns into fitness landscapes for use in interpreting the environmental constraints that have shaped the evolution of this process through Earth history.

No MeSH data available.