Microbial community shifts influence patterns in tropical forest nitrogen fixation

Reed, Sasha C.; Townsend, Alan R.; Cleveland, Cory C.; Nemergut, Diana R.

doi:10.1007/s00442-010-1649-6

Cited by 131 publications

(99 citation statements)

References 67 publications

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“…Beyond forest ecosystems, a meta-analysis of the effects of elevated CO 2 on N fixation rates was not able to detect an effect of soil N fertilization on N fixation rates (44). As both diversity and abundance of nitrogenase genes are positively correlated with rates of N fixation (8,9), our molecular analysis provides novel insight into the interactive effects of CO 2 and N fertilization on potential N fixation rates.…”

Section: Discussionmentioning

confidence: 85%

“…However, N fertilization or other additions often lower fixation rates, since free-living N-fixing bacteria are typically facultative and can potentially suppress N fixation when N is relatively abundant (1). The community diversity of soil N-fixing bacteria shifts quickly and is a strong predictor of N fixation activity (8,9). Based on these factors, we hypothesized that long-term elevated atmospheric CO 2 would increase the abundance of N-fixing bacteria and alter bacterial community composition but that increased inorganic N supply through fertilization would suppress the CO 2 enhancement of Nfixing-bacterial abundance.…”

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confidence: 99%

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Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂

Berthrong

Yeager

Gallegos-Graves

et al. 2014

Appl Environ Microbiol

132

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c Biological nitrogen fixation is the primary supply of N to most ecosystems, yet there is considerable uncertainty about how Nfixing bacteria will respond to global change factors such as increasing atmospheric CO 2 and N deposition. Using the nifH gene as a molecular marker, we studied how the community structure of N-fixing soil bacteria from temperate pine, aspen, and sweet gum stands and a brackish tidal marsh responded to multiyear elevated CO 2 conditions. We also examined how N availability, specifically, N fertilization, interacted with elevated CO 2 to affect these communities in the temperate pine forest. Based on data from Sanger sequencing and quantitative PCR, the soil nifH composition in the three forest systems was dominated by species in the Geobacteraceae and, to a lesser extent, Alphaproteobacteria. The N-fixing-bacterial-community structure was subtly altered after 10 or more years of elevated atmospheric CO 2 , and the observed shifts differed in each biome. In the pine forest, N fertilization had a stronger effect on nifH community structure than elevated CO 2 and suppressed the diversity and abundance of N-fixing bacteria under elevated atmospheric CO 2 conditions. These results indicate that N-fixing bacteria have complex, interacting responses that will be important for understanding ecosystem productivity in a changing climate. N itrogen is the most common nutrient limiting productivity in terrestrial ecosystems and enters ecosystems predominantly through bacterial fixation. However, we lack a clear understanding of how N-fixing bacteria respond to climate change drivers or how conserved those responses might be across biomes in a geographic region. Nonagricultural biomes in the eastern United States that experience elevated atmospheric CO 2 and increasing N deposition include hardwood forests to the north, pine forests to the south, and brackish marsh areas along the eastern seaboard. Rising atmospheric CO 2 concentrations and shifting patterns of N deposition can interact and affect N fixation processes in soil (1). To determine if populations of N-fixing bacteria in soils of different biomes showed similarities in composition and in responses to elevated CO 2 , we conducted a systematic survey of soil N-fixing bacterial communities across four biomes in the eastern United States, utilizing long-term, free-air CO 2 enrichment (FACE) experiments (2). One of these field experiments combined elevated CO 2 and N fertilization treatments, allowing us to determine their interactive effects on the N-fixing community in a pine forest in the southeastern United States.Progressive N limitation theory proposes that ecosystems become more N limited with rising CO 2 , which suggests that the continued sequestration of CO 2 in terrestrial biomass will require greater N fixation inputs (3, 4). The increased ecosystem demand for N under elevated CO 2 has been documented after several years of whole-forest CO 2 enrichment (5, 6). N-fixing bacteria, which span many taxonomic groups with high levels of ...

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Section: Discussionmentioning

confidence: 85%

mentioning

confidence: 99%

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂

Berthrong

Yeager

Gallegos-Graves

et al. 2014

Appl Environ Microbiol

132

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“…The lack of response to additional mineral N may also indicate the soil has a suffi cient supply of this element, as a result of N-fi xation by either symbiotic association or free-living microorganisms (Cleveland et al, 1999;Reed et al, 2010).…”

Section: Effect Of Nutrient Additionmentioning

confidence: 99%

Do soil fertilization and forest canopy foliage affect the growth and photosynthesis of Amazonian saplings?

Magalhães

Marenco

Camargo

2014

Sci. agric. (Piracicaba, Braz.)

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Most Amazonian soils are highly weathered and poor in nutrients. Therefore, photosynthesis and plant growth should positively respond to the addition of mineral nutrients. Surprisingly, no study has been carried out in situ in the central Amazon to address this issue for juvenile trees. The objective of this study was to determine how photosynthetic rates and growth of tree saplings respond to the addition of mineral nutrients, to the variation in leaf area index of the forest canopy, and to changes in soil water content associated with rainfall seasonality.We assessed the effect of adding a slow-release fertilizer. We determined plant growth from 2010 to 2012 and gas exchange in the wet and dry season of 2012. Rainfall seasonality led to variations in soil water content, but it did not affect sapling growth or leaf gas exchange parameters. Although soil amendment increased phosphorus content by 60 %, neither plant growth nor the photosynthetic parameters were infl uenced by the addition of mineral nutrients. However, photosynthetic rates and growth of saplings decreased as the forest canopy became denser.Even when Amazonian soils are poor in nutrients, photosynthesis and sapling growth are more responsive to slight variations in light availability in the forest understory than to the availability of nutrients. Therefore, the response of saplings to future increases in atmospheric [CO 2 ] will not be limited by the availability of mineral nutrients in the soil.

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“…Plant-specific differences in the nitrogen-fixing bacterial community may be related to plant species, biomass, the chemical composition of litter and root exudates (Shaffer et al, 2000;Bürgmann et al, 2005;Hsu and Buckley, 2009;Knelman et al, 2012). Soil physicochemical factors, such as pH and water content (Zhan and Sun, 2011), microbial biomass carbon and microbial biomass nitrogen (Hayden et al, 2010), total nitrogen and total potassium (Teng et al, 2009;Hayden et al, 2010), total phosphorus and reactive phosphorus (Reed et al, 2010;Zou et al, 2011;Romero et al, 2012), electrical conductivity (Hayden et al, 2010;Hamilton et al, 2011) and nutrient level (Jasrotia and Ogram, 2008;Zhan and Sun, 2012), have also been identified as drivers of nifH gene diversity and abundance in many environments.…”

Section: S Tai Et Al: High Diversity Of Nitrogen-fixing Bacteriamentioning

confidence: 99%

High diversity of nitrogen-fixing bacteria in the upper reaches of the Heihe River, northwestern China

et al. 2013

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Vegetation plays a key role in water conservation in the southern Qilian Mountains (northwestern China), located in the upper reaches of the Heihe River. Nitrogen-fixing bacteria are crucial for the protection of the nitrogen supply for vegetation in the region. In the present study, nifH gene clone libraries were established to determine differences between the nitrogen-fixing bacterial communities of the Potentilla parvifolia shrubland and the Carex alrofusca meadow in the southern Qilian Mountains. All of the identified nitrogen-fixing bacterial clones belonged to the Proteobacteria. At the genus level, Azospirillum was only detected in the shrubland soil, while Thiocapsa, Derxia, Ectothiorhodospira, Mesorhizobium, Klebsiella, Ensifer, Methylocella and Pseudomonas were only detected in the meadow soil. The phylogenetic tree was divided into five lineages: lineages I, II and III mainly contained nifH sequences obtained from the meadow soils, while lineage IV was mainly composed of nifH sequences obtained from the shrubland soils. The Shannon–Wiener index of the nifH genes ranged from 1.5 to 2.8 and was higher in the meadow soils than in the shrubland soils. Based on these analyses of diversity and phylogeny, the plant species were hypothesised to influence N cycling by enhancing the fitness of certain nitrogen-fixing taxa. The number of nifH gene copies and colony-forming units (CFUs) of the cultured nitrogen-fixing bacteria were lower in the meadow soils than in the shrubland soils, ranging from 0.4 × 10⁷ to 6.9 × 10⁷ copies g⁻¹ soil and 0.97 × 10⁶ to 12.78 × 10⁶ g⁻¹ soil, respectively. Redundancy analysis (RDA) revealed that the diversity and number of the nifH gene copies were primarily correlated with aboveground biomass in the shrubland soil. In the meadow soil, nifH gene diversity was most affected by altitude, while copy number was most impacted by soil-available K. These results suggest that the nitrogen-fixing bacterial communities beneath Potentilla were different from those beneath Carex

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Microbial community shifts influence patterns in tropical forest nitrogen fixation

Cited by 131 publications

References 67 publications

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂

Do soil fertilization and forest canopy foliage affect the growth and photosynthesis of Amazonian saplings?

High diversity of nitrogen-fixing bacteria in the upper reaches of the Heihe River, northwestern China

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Microbial community shifts influence patterns in tropical forest nitrogen fixation

Cited by 131 publications

References 67 publications

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO 2

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO 2

Do soil fertilization and forest canopy foliage affect the growth and photosynthesis of Amazonian saplings?

High diversity of nitrogen-fixing bacteria in the upper reaches of the Heihe River, northwestern China

Contact Info

Product

Resources

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Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂

Nitrogen Fertilization Has a Stronger Effect on Soil Nitrogen-Fixing Bacterial Communities than Elevated Atmospheric CO ₂