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Harvard Forest Data Archive

HF256

Temperature Sensitivity of Microbial Activity in Three Forest Soils at Harvard Forest 2010-2011

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Data

Overview

  • Lead: John Drake, Adrien Finzi
  • Investigators: Marc-Andre Giasson
  • Contact: Adrien Finzi
  • Start date: 2010
  • End date: 2011
  • Status: completed
  • Location: Prospect Hill Tract (Harvard Forest)
  • Latitude: +42.347058 to +42.545576
  • Longitude: -72.335288 to -72.172284
  • Elevation:
  • Taxa: Fraxinus americana (white ash), Quercus rubra (red oak), Tsuga canadensis (eastern hemlock)
  • Release date: 2015
  • Revisions:
  • EML file: knb-lter-hfr.256.2
  • DOI: digital object identifier
  • Related links:
  • Study type: short-term measurement
  • Research topic: soil carbon and nitrogen dynamics
  • LTER core area: populations, organic matter
  • Keywords: biogeochemistry, carbon, hemlock, microbes, nitrogen mineralization, oak, soil respiration
  • Abstract:

    We evaluated possible seasonal variation in the temperature sensitivity of microbially mediated soil fluxes related to decomposition (net N mineralization, net nitrification, proteolysis, the maximum velocity (Vmax) of proteolysis, microbial respiration, and the Vmax of four soil exo-enzymes) across forests dominated by eastern hemlock (Tsuga canadensis), white ash (Fraxinus americana), and red oak (Quercus rubra) in Harvard Forest. We asked two simple questions: (1) do temperature sensitivities vary across forest types or different steps of the decomposition process, and (2) do temperature sensitivities display plasticity on a seasonal time frame?We observed substantial variation in temperature sensitivities (Q10 and R10 values) across the different fluxes and forest types. The ash soils exhibited the strongest temperature sensitivities and the mineral-N fluxes exhibited higher temperature sensitivities relative to the proteolytic fluxes or microbial respiration. The Vmax of soil exo-enzymes varied considerably in an interactive manner across forests and time, and the response of some enzymes was consistent with the thermal plasticity. The enzymatic kinetic properties Vmax and Km (half-saturation constant) were strongly correlated with slopes that differed across enzymes, reflecting an enzyme-specific tradeoff between maximum catalytic rate and substrate-binding efficiency. Generally, Q10 values were largely constant, but R10 values varied in a manner consistent with distinct seasonal plasticity. There was a consistent seasonal shift in R10 values coincident with snowmelt, suggesting that the time following snowmelt is a particularly interesting and dynamic period of microbial activity in these temperate forests.

  • Methods:

    For detailed methods, please see: Drake, J. E., M.-A. Giasson, K. J. Spiller, and A. C. Finzi. 2013. Seasonal plasticity in the temperature sensitivity of microbial activity in three temperate forest soils. Ecosphere 4(6):77. http://dx.doi.org/10.1890/ES13-00020.1.

  • Use:

    This dataset is released to the public under Creative Commons license CC BY (Attribution). Please keep the designated contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement.

  • Citation:

    Drake J, Finzi A. 2015. Temperature Sensitivity of Microbial Activity in Three Forest Soils at Harvard Forest 2010-2011. Harvard Forest Data Archive: HF256.

Detailed Metadata

hf256-01: microbial exo-enzyme activity

  1. year: year of sampling
  2. month: month of sampling
  3. day: day of sampling
  4. date: date of sampling
  5. species: dominant tree species in the plot
    • FRAM: white ash
    • QURU: red oak
    • TSCA: eastern hemlock
  6. plot: plot number
  7. substrate: enzyme substrate used
    • AP: acid phosphatase
    • BG: b-1,4-glucosidase
    • CBH: cellobiohydrolase
    • NAG: b-N-acetylglucosaminidase
  8. substrate.conc: enzyme substrate concentration (unit: micromole / missing value: NA)
  9. activity: microbial exo-enzyme activity measured (μmol substrate converted/g soil/hour) (unit: micromolePerGramPerHour / missing value: NA)

hf256-02: exo-enzymes kinetics

  1. year: year of sampling
  2. month: month of sampling
  3. day: day of sampling
  4. date: date of sampling
  5. species: dominant tree species in the plot
    • FRAM: white ash
    • QURU: red oak
    • TSCA: eastern hemlock
  6. plot: plot number
  7. substrate: enzyme substrate used
    • AP: acid phosphatase
    • BG: b-1,4-glucosidase
    • CBH: cellobiohydrolase
    • NAG: b-N-acetylglucosaminidase
  8. v.max: maximum exo-enzyme activity at saturating substrate concentrations (unit: micromolePerGramPerHour / missing value: NA)
  9. km: half-saturation constant, or the substrate concentration at which the exo-enzyme activity is half the v.max value (unit: micromole / missing value: NA)

hf256-03: soil carbon and nitrogen

  1. year: year of sampling
  2. month: month of sampling
  3. day: day of sampling
  4. date: date of sampling
  5. species: dominant tree species in the plot
    • FRAM: white ash
    • QURU: red oak
    • TSCA: eastern hemlock
  6. plot: plot number
  7. n: soil percent nitrogen (unit: dimensionless / missing value: NA)
  8. c: soil percent carbon (unit: dimensionless / missing value: NA)

hf256-04: soil processes

  1. year: year of sampling
  2. month: month of sampling
  3. day: day of sampling
  4. date: date of sampling
  5. doy: julian day of sampling (unit: nominalDay / missing value: NA)
  6. species: dominant tree species in the plot
    • FRAM: white ash
    • QURU: red oak
    • TSCA: eastern hemlock
  7. plot: plot number
  8. season: sampling season
  9. dry.wet: soil dry mass:wet mass ratio (unit: dimensionless / missing value: NA)
  10. temp: incubation temperature (unit: celsius / missing value: NA)
  11. net.n.min: net N mineralization (μg N/g dry soil/day) (unit: microgramsPerGramPerDay / missing value: NA)
  12. net.n.nit: net N nitrification(μg N/g dry soil/day) (unit: microgramsPerGramPerDay / missing value: NA)
  13. proteolysis: proteolysis, the rate of protein depolymerization into free amino acids (μg N/g dry soil/hour) (unit: microgramsPerGramPerHour / missing value: NA)
  14. proteolysis.c: proteolysis under saturating protein substrate, 0.6% casein in soil solution (μg N/g dry soil/hour) (unit: microgramsPerGramPerHour / missing value: NA)
  15. rsoil: soil respiration (μg C/g dry soil/hr) (unit: microgramsPerGramPerHour / missing value: NA)