Joanna C. Carey Jianwu Tang Pamela H. Templer Kevin D. Kroeger Thomas W. Crowther Andrew Burton Jeffrey S. Dukes Bridget Emmett Serita Frey Mary Heskel Lifen Jiang Megan Machmuller Jacqueline E. Mohan Anne Marie Panetta Peter B. Reich Xin Wang Steven D. Allison Chrisopher Bamminger Scott D. Bridgham Scott L. Collins Giovanbattista de Dato William C. Eddy Brian J. Enquist Marc Estiarte John Harte Amanda Henderson Bart R. Johnson Klaus S. Larsen Yiqi Luo Sven Marhan Jerry Melillo Josep Peñuelas Laurel Pfeifer-Meister Christian Poll Edward B. Rastetter Andy Reinmann Lorien L. Reynolds Inger K. Schmidt Gaius R. Shaver Aaron L. Strong Vidya Suseela Albert Tietema 2016 Spreadsheet (csv file) Reston, VA U.S. Geological Survey http://dx.doi.org/10.5066/F7MK6B1X Joanna C. Carey Jianwu Tang Pamela H. Templer Kevin D. Kroeger Thomas W. Crowther Andrew Burton Jeffrey S. Dukes Bridget Emmett Serita Frey Mary Heskel Lifen Jiang Megan Machmuller Jacqueline E. Mohan Anne Marie Panetta Peter B. Reich Xin Wang Steven D. Allison Chrisopher Bamminger Scott D. Bridgham Scott L. Collins Giovanbattista de Dato William C. Eddy Brian J. Enquist Marc Estiarte John Harte Amanda Henderson Bart R. Johnson Klaus S. Larsen Yiqi Luo Sven Marhan Jerry Melillo Josep Peñuelas Laurel Pfeifer-Meister Christian Poll Edward B. Rastetter Andy Reinmann Lorien L. Reynolds Inger K. Schmidt Gaius R. Shaver Aaron L. Strong Vidya Suseela Albert Tietema 2016 This dataset is the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3800 observations representing 27 temperature manipulation studies, spanning nine biomes and nearly two decades of warming experiments. Data for this study were obtained from a combination of unpublished data and published literature values. We find that although warming increases soil respiration rates, there is limited evidence for a shifting respiration response with experimental warming. We also note a universal decline in the temperature sensitivity of respiration at soil temperatures >25°C. This dataset includes 3817 observations, from control (n=1812), first (i.e., lowest or sole) level warming (n=1812), second (higher) level warming (n=179, four studies), and third-level warming (n=14, one study). Experiment locations ranged from 33.5 to 68.4 degrees N latitude and the duration of warming at experiments ranged from <1 to 22 years (average 5.1 years). Depths of soil temperature (1-10 cm) and moisture measurements (5-30) ranged across studies, but were always consistent between warmed and control plots within a particular study. Each site was classified into a particular biome (grassland, northern shrubland (i.e., peatlands and heathlands), southern shrubland (i.e., Mediterranean or sub-tropical shrublands)), tundra, desert, meadow, temperate agriculture, temperate forest and boreal forest) by the associated principal investigator (PI). The data included in this dataset were collected at 27 individual warming studies for the purpose of determining how future climatic warming will alter soil respiration rates, among other response variables not reported in this dataset. This dataset was generated with the purpose of synthesizing the results of these individual studies to better understand how soil respiration will respond to future climatic warming at the biome scale and at high temporal frequencies. 1994 2014 ground condition Complete Not planned -138.9 42.9 68.4 33.5 USGS Metadata Identifier USGS:580a40cde4b0f497e7906426 None soil respiration soil moisture soil temperature experimental warming instantaneous data climate change Boreal Forest Desert Meadow Northern Shrubland Southern Shrubland Temperate Agriculture Temperate Forest Temperate Grassland Wet Sedge Tundra USGS Thesaurus soil sciences Ecology none The authors of these data require that data users contact them regarding intended use and to assist with understanding limitations and interpretation. The authors of these data require data users seek explicit permission before publishing new analysis and results from these data prior to 2050. Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Joanna Carey The Ecosystems Center mailing and physical

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Woods Hole MA 315.521.0562 USA 02543 jcarey@mbl.edu USGS John Wesley Powell Center Larry V. Hedges Jessica Gurevitch Peter S. Curtis 1999 Ecology Vol. 80, No. 4, pp. 1150-1156 Hoboken, NJ Wiley http://www.jstor.org/stable/177062 Spot-checking data, analysis of model residuals, sending data to another team member to re-do analysis and double check results. No formal logical accuracy tests were conducted We did not include respiration data if corresponding soil moisture or soil temperature data was not available. Our analysis includes only warming treatment, not combined with other types of treatment (i.e. no measurements from warmed+nitrogen addition, or warmed+drought are included). All years of data are represented. At a few sites, certain soil attributes were not available (i.e. NA). No formal positional accuracy tests were conducted. Each site ID represents a specific field site. A literature search, which was conducted on September 22, 2014 using Web of Science, produced five publications presenting non-aggregated instantaneous data that were extractable. Unpublished values make up the majority of the data in the dataset. We obtained unpublished data by first creating a list of all known experimental warming studies globally and asking the principal investigators to supply soil respiration data with corresponding soil temperature and moisture values. All individual fluxes were calculated by individual PIs. The experiments generally had several replicate plots for each treatment. We averaged all plot-scale values for each sampling event to obtain one average (± SD) for each treatment for each sampling event (‘sampling events’ typically refer to a single day of sampling, although several studies complete full suites of sampling (i.e., ‘sampling events’) from all plots in both morning and afternoon). Only soil respiration values with corresponding soil moisture and soil temperature values from experimental warming studies were included in our analysis. Only observations from single-factor treatments (i.e., warming) were used, excluding values that combined warming with other treatments (e.g., precipitation or nitrogen manipulation). Four studies included more than one level of warming treatment (e.g., both 1.5 and 3 degrees Celsius warming treatments); in these cases, data from all levels of warming were used. All data were reported as instantaneous change in CO2 efflux over a fixed area, with belowground (i.e., roots and rhizomes), but not aboveground vegetation, included. Only biomes with at least 100 data points are analyzed individually, which prevented Meadow and Tundra from being analyzed in isolation, as these did not have at least 100 data points each. Therefore they are found in the dataset but not in the publication, Carey et al. 2016. The following are the published sources of data: Reynolds LL, Johnson BR, Pfeifer-Meister L, Bridgham SD (2015) Soil respiration response to climate change in Pacific Northwest prairies is mediated by a regional Mediterranean climate gradient. Glob Chang Biol 21(1):487–500. Lellei-Kovács E, et al. (2008) Experimental warming does not enhance soil respiration in a semiarid temperate forest-steppe ecosystem. Community Ecol 9(1):29–37. de Dato GD, De Angelis P, Sirca C, Beier C (2009) Impact of drought and increasing temperatures on soil CO2 emissions in a Mediterranean shrubland (gariga). Plant Soil 327(1-2):153–166. Saleska SR, Harte J, Torn MS (1999) The effect of experimental ecosystem warming on CO2 fluxes in a montane meadow. Glob Chang Biol 5(2):125–141. Flanagan LB, Sharp EJ, Letts MG (2013) Response of plant biomass and soil respiration to experimental warming and precipitation manipulation in a Northern Great Plains grassland. Agric For Meteorol 173:40–52. Jarvi MP, Burton AJ (2013) Acclimation and soil moisture constrain sugar maple root respiration in experimentally warmed soil. Tree Physiol 33(9):949–959. Suseela V, Conant RT, Wallenstein MD, Dukes JS (2012) Effects of soil moisture on the temperature sensitivity of heterotrophic respiration vary seasonally in an old-field climate change experiment. Glob Chang Biol 18(1):336–348. Allison SD, Treseder KK (2008) Warming and drying suppress microbial activity and carbon cycling in boreal forest soils. Glob Chang Biol 14(12):2898–2909. Allison SD, McGuire KL, Treseder KK (2010) Resistance of microbial and soil properties to warming treatment seven years after boreal fire. Soil Biol Biochem 42(10):1872–1878. Poll C, Marhan S, Back F, Niklaus PA, Kandeler E (2013) Field-scale manipulation of soil temperature and precipitation change soil CO2 flux in a temperate agricultural ecosystem. Agric Ecosyst Environ 165:88–97. Johnson LC, et al. (2000) Plant carbon - nutrient interactions control CO2 exchange in Alaskan wet sedge tundra ecosystems. Ecology 81(2):453–469. Reinsch, S., Sowerby, A., Emmett, B.A. (2016) Fortnightly soil respiration data from Climoor fieldsite in Clocaenog Forest 1999 – 2015. DOI: 10.5285/[2]c0822023-0ec2-425f-8bf9-a546ce281ee0 Reinsch, S., Sowerby, A., Emmett, B.A. (2016) Daily plot level (micro meteorological) data at Climoor field site in Clocaenog Forest 1998-2015. DOI: http://doi.org/10.5285/afb994e5-b33d-48b4-ad29-d374b1f9f3c8 2014 Meta-analysis using log response ratios, standardized mean difference. We used methods from Hedges et al. 1999. We used a log-quadratic temperature response function, as this was the best supported model for most biomes. ln(R)=y0 +y1T+y2T^2 where R is soil respiration (micro mol C m^-2 s-1) and T is soil temperature (Celsius). Using this basic model, we further included warming treatment as an interaction term in order to evaluate differences in the temperature response between warmed versus control plots. We used this model for all biomes, except the boreal forest and northern shrublands, where a log-linear model (ln(R) = y0 + y1T) was the better fit. We evaluated two specific features of the temperature response function: (i) the temperature sensitivity (i.e., the shape of the curve denoted by the first derivative of Eq. 1: (= d ln(R)/dT, Table 1) and (ii) the magnitude of the respiration response when T = 0. More information can be found in the methods section of the paper Carey et al. 2016. 2015 Standard methods for grain size analysis were used by individual PIs in the original studies. Unknown Added keywords section with USGS persistent identifier as theme keyword. 20200807 U.S. Geological Survey VeeAnn A. Cross Marine Geologist Mailing and Physical

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Woods Hole MA 02543-1598 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov Soil respiration synthesis data This dataset is the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3800 observations representing 27 temperature manipulation studies. Producer defined SiteID Each Site ID is a specific site. The Site ID number was randomly generated. Producer defined 1 67 Year Year that sample was collected Producer defined 1994 2014 DOY Day of year that sample was collected. Note that half a day represents noon and is represented by (.5). For example, 366.5 is noon on December 31st of a leap year. Producer defined 1.5 366.5 Season Season of the year Producer defined Growing Growing season - when plants are growing Producer Defined Non-Growing Non-growing season - when plants are not growing Producer Defined Shoulder Shoulder season - takes into account months of transition and also annual variability Producer Defined Treatment Warming treatment Producer defined C C for control Producer Defined W W for first or sole level warmed treatment Producer Defined W1 W1 for second level warmed treatment Producer Defined W2 W2 for third level warmed treatment Producer Defined n_Replicates Number of replicates (plot level) Producer defined 2 10 R_avg_umol.m2.s Instantaneous flux of soil respiration. Micro mol of carbon per square meter per second Producer defined 0.01 13.30 micro C moles m-2 s-1 (micro mol of carbon per square meter per second) Resp_stdev Standard deviation of instantaneous flux of soil respiration. Any NA values stand for data not available – these values occur when PIs did not measure this particular attribute. Producer defined 0 5.13 micro C moles m-2 s-1 (micro mol of carbon per square meter per second) Moist_avg_cm3.cm.3 Instantaneous value of soil moisture Producer defined 0.0011 0.8160 cm^3 cm-3 Moist_stdev Standard deviation of instantaneous soil moisture. Any NA values stand for data not available – these values occur when PIs did not measure this particular attribute. Producer defined 0 0.2425 cm^3 cm-3 Stemp_Avg_C Instantaneous value of soil temperature Producer defined -3.3228 41.49 Degrees Celsius Stemp_SD_C Standard deviation of instantaneous soil temperature Producer defined 0 8.3562 Degrees Celsius WarmingStart Year that warming commenced at field site Producer defined 1989 2014 EcosystemType Type of biome. We used standard definitions of biomes found in an English dictionary. Producer defined BorealForest Boreal Forest Producer Defined TemperateForest Temperate Forest Producer Defined TemperateGrassland Temperate Grassland Producer Defined Meadow Meadow Producer Defined N_Shrubland Northern Shrublands (i.e., peatlands and heathlands) Producer Defined S_Shrubland Southern Shrublands (i.e., Mediterranean or sub-tropical shrublands) Producer Defined TemperateAgriculture Temperate Agriculture Producer Defined Desert Desert Producer Defined WetSedgeTundra Wet Sedge Tundra Producer Defined sand_pct Soil texture type - percent sand. Any NA values stand for data not available – these values occur when PIs did not measure this particular attribute. Producer defined 9 94.4 Percent silt_pct Soil texture type - percent silt. Any NA values stand for data not available – these values occur when PIs did not measure this particular attribute. Producer defined 0 69 Percent clay_pct Soil texture type - percent clay. Any NA values stand for data not available – these values occur when PIs did not measure this particular attribute. Producer defined 0.5 31.2 Percent U.S. Geological Survey - ScienceBase mailing and physical

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Denver CO 80225 USA 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. CSV http://dx.doi.org/10.5066/F7MK6B1X https://www.sciencebase.gov/catalog/file/get/580a40cde4b0f497e7906426 none 20211116 Joanna Carey The Ecosystems Center mailing and physical

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Woods Hole MA 02543 USA 315.521.0562 whsc_data_contact@usgs.gov The metadata contact email address is a generic address in the event the metadata contact is no longer with the USGS or the email is otherwise invalid. Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998