Find research datasets worth reusing

Effects of Forest Fragmentation on Carbon Sequestration and Respiration at Harvard Forest since 2016

Forest loss/fragmentation can have profound impacts on the terrestrial carbon (C) cycle by reducing forest uptake of carbon dioxide (CO2; the primary driver of anthropogenic climate change) through photosynthesis and C storage in forest biomass. Relative to intact rural forests, trees growing in forest fragments within developed landscapes typically experience conditions that can enhance growth such as warmer and longer growing seasons (i.e. urban heat island effect) and greater light and nutrient availability (e.g., nitrogen deposition) as well as conditions that can hinder growth such as increased exposure to damaging pollutants such as ozone and higher rates of disturbance. Our research quantifies the impact of fragmentation on C uptake and respiration near forest edges. In 2016 six 600‐m2 plots were installed along forest edges at the HF, measuring 20 m along the forest edge and extending 30 m into the forest perpendicular to the forest edge. Plot biomass was mapped and tree cores were taken in all trees >10cm diameter. The plots were installed at multiple edge aspects and adjacent land cover types (three meadows, two pastures, and one road). Within each plot, a pair of polyvinyl chloride soil respiration collars 20 cm in diameter × 7 cm tall and located 10 m apart was inserted approximately 2 cm into the soil at four distances from the edge (0, 10, 20, and 30m). Each plot had n = 8 collars for a total of n = 48 collars. Following installation, collars were left in the soil for at least 2 weeks to equilibrate. Air temperature, relative humidity, soil temperature, and soil moisture were logged along the center plot transect.

Nonstructural Carbon, Phenology and Wood Formation in Three Tree Species at Harvard Forest 2017-2019

This data set comprises various observations and measurements across the 2017 to 2019 growing season for seven red maple (Acer rubrum), eight red oak (Quercus rubra), and six white pine (Pinus strobus) in the Prospect Hill Tract of Harvard Forest. The observations include spring and fall leaf phenology and basic allometry, such as diameter at breast height and height. For the leaf phenology, we followed the protocol from John O’Keefe (HF003). Measurements include wood growth data from weekly microcores and a three time characterisation of growing season nonstructural carbon concentrations (soluble sugars and starch) for stems and leaves. Additionally, stem CO2 efflux was measured once a month for the 2018 growing season and weekly for the 2019 growing season.

Effects of Soil Warming and Substrate Complexity on Microbial Carbon Use Efficiency at Harvard Forest 2017

Soil microbial carbon use efficiency (CUE) is a combination of growth and respiration, which may respond differently to climate change depending on physical protection of soil carbon (C) and its availability to microbes. In a mid-latitude hardwood forest in central Massachusetts, 27 years of soil warming (+5 ◦C) has resulted in C loss and altered soil organic matter (SOM) quality, yet the underlying mechanisms remain unclear. Here, we hypothesized that long-term warming reduces physical aggregate protection of SOM, microbial CUE, and its temperature sensitivity. Soil was separated into macroaggregate (250–2000 μm) and microaggregate (less than 250 μm) fractions, and CUE was measured with 18O-enriched water in samples incubated at 15 and 25 ◦C for 24 h. We found that long-term warming reduced soil C and nitrogen concentrations and extracellular enzyme activity in macroaggregates, but did not affect physical protection of SOM. Long-term warming showed little effect on CUE or microbial biomass turnover time because it reduced both growth and respiration. However, CUE was less temperature sensitive in macroaggregates from the warmed compared to the control plots. Our findings suggest that microbial thermal responses to long-term warming occur mostly in soil compartments where SOM is less physically protected and thus more vulnerable to microbial degradation.

openCC0Mar 2024View details →

Canopy-Atmosphere Exchange of Carbon, Water and Energy at Harvard Forest EMS Tower since 1991

The tower-based CO2 measurements and key meteorological drivers are intended to examine how regional and ecosystem level processes in a mid-latitude forest contribute to global carbon cycling. Specifically, we endeavor to understand quantitatively how and why forested ecosystems take up or release carbon, on time scales from hours to decades, and to elucidate responses to climate changes and management interventions. The tower was installed 1989 and the resulting eddy-flux measurements constitute the longest running record of the net-ecosystem carbon exchange in a North American Forest. The resulting long-term record of Net Ecosystem Exchange (NEE) has shown the effects of climate anomalies on carbon fluxes for seasonal and annual time scales. For example, reduced soil frost allows greater respiration in the winter leading to lower C sequestration. Cumulative gross photosynthesis depends on when the canopy emerges in the spring. Warmer springtime temperatures lead to greater uptake of C. As the NEE record is extended and augmented by supporting ecological measurements, we can further identify longer-term effects of climate perturbations on carbon fluxes and further define the relationship between stand history and carbon sequestration. Climatic anomalies in one season or year may have a longer-term effect on the sequestration of carbon in subsequent seasons or years. The flux and ecological measurements are coordinated with studies at other sites through the AmeriFlux network. By examining the relationships between carbon fluxes and the driving physical and biological variables across a range of sites we are enhancing understanding of the processes that control NEE.

Carbon Biogeochemistry of Forested Headwater Streams at Harvard Forest 2006-2007

Headwater streams make up greater than 80% of total channel length in the United States and play important roles in regulating nutrient, organic matter, and sediment fluxes from terrestrial to downstream ecosystems. Headwater streams are common features of many upland-forested watersheds in New England, yet are not explicitly factored into forest water, carbon, and nutrient budgets. Here we report on recent efforts to examine terrestrial and stream ecosystem linkages in carbon biogeochemistry in a hemlock-dominated watershed. A prototype stream biogeochemical system (SBS) was tested at the Harvard Forest LTER. The SBS allows a suite of stream water properties to be characterized in real-time over extended periods of time thus allowing questions to be asked at a wide range of time scales. The prototype SBS was field-tested in Bigelow Brook West on the Prospect Hill research tract at Harvard Forest. Bigelow Brook West was selected because the watershed’s hydrology, stream ecology, forest composition, land-use history, and carbon sequestration have been characterized, thus aiding the interpretation of SBS data and facilitating multi-disciplinary research. The prototype system monitors stream and air temperature, pCO2 , colored dissolved organic matter, total suspended sediments, PAR, water depth, pH, and dissolved O2. Independent estimates of organic and inorganic water chemistry were used to validate and interpret SBS data. Here we report on preliminary findings from the pilot SBS at Harvard Forest to highlight the usefulness of headwater stream chemistry data to a wide-diversity of ecosystem scientists. 1) Low pH constrains dissolved inorganic carbon solute fluxes to downstream ecosystems. 2) CO2 concentrations were always supersaturated in Bigelow Brook, averaging about 6x atmospheric values in summer, thus the stream is an important source of CO2 to the atmosphere. Variation in CO2 appears to be linked to multiple mechanisms including changes in stream temperature,

Belowground Carbon Observatory Network (BeCON) at Harvard Forest since 2020

A central goal of the recent Harvard Forest C Synthesis activity was to identify high-priority needs for C-cycle research at the forest. While there were a number of areas needing follow-up research, belowground C pools and fluxes remain the single largest gap in the C budget and therefore our understanding of the C cycle of the forest. To this end, we developed the Belowground Carbon Observatory Network (BeCON) as a part of the LTER-VI grant proposal. The long-term goal of BeCON is to understand temporal and spatial variations in belowground C pools in response to the various environmental changes the forest now faces [e.g., rising CO2, changes in atmospheric N, S and O3 chemistry, invading insects, land-use change, immigrating (large) herbivores]. There are two great challenges in achieving this goal: (1) excessive spatial heterogeneity in belowground C pools; and (2) lack of automated systems for analysis. These characteristics make it very difficult to quantify changes because the work is intrinsically labor intensive with low replication and the noisy data lead to low statistical power. Here, we measured soil carbon content, root biomass and carbon content, and annual root productivity following the protocols for BeCON.

Carbon Cycle Dynamics in Soil Warming Experiments at Harvard Forest 2019

Microbes are responsible for cycling carbon (C) through soils, and predicted changes in soil C stocks under climate change are highly sensitive to shifts in the mechanisms assumed to control the microbial physiological response to warming. Two mechanisms have been suggested to explain the long-term warming impact on microbial physiology: microbial thermal acclimation and changes in the quantity and quality of substrates available for microbial metabolism. Yet studies disentangling these two mechanisms are lacking. To resolve the drivers of changes in microbial physiology in response to long-term warming, we sampled soils from 13- and 28-year-old soil warming experiments in different seasons. We performed short-term laboratory incubations across a range of temperatures to measure the relationships between temperature sensitivity of physiology (growth, respiration, carbon use efficiency, and extracellular enzyme activity) and the chemical composition of soil organic matter. We observed apparent thermal acclimation of microbial respiration, but only in summer, when warming had exacerbated the seasonally-induced, already small dissolved organic matter pools. Irrespective of warming, greater quantity and quality of soil carbon increased the extracellular enzymatic pool and its temperature sensitivity. We propose that fresh litter input into the system seasonally cancels apparent thermal acclimation of C-cycling processes to decadal warming. Our findings reveal that long-term warming has indirectly affected microbial physiology via reduced C availability in this system, implying that earth system models including these negative feedbacks may be best suited to describe long-term warming effects on these soils.

Column-Averaged Atmospheric Carbon and Water at Harvard Forest since 2018

Ground-based total-atmospheric column measurements of CO2, CH4, CO, and H2O began at Harvard Forest in May 2018 using a solar-viewing Fourier Transform Spectrometer (Bruker EM27/Sun). Observations are made from a platform near the Fisher Meteorological Tower throughout the year on sunny days. Total column observations are sensitive to regional carbon fluxes, and are less impacted by changes in the boundary layer height than tower based in-situ observations. The Harvard Forest observations are complemented by an identical instrument operated on the Harvard campus in Cambridge MA. The two sensors are used to support studies of urban emissions, regional transport, and forest-atmosphere exchange. In addition, the total-column measurements provide key validation data for satellite measurements of greenhouse gases.

Net Carbon Exchange of a Young Upper-Slope Deciduous Forest at Harvard Forest LPH Tower 2002-2010

This data set contains sensible heat exchange, water vapor exchange and carbon exchange as well as environmental data for a deciduous forest dominated by red oak (Quercus rubra). It is 1.1 km WNW of the EMS tower where continuous eddy covariance measurements began in 1992 (see HF004). The High Deciduous site is about 385 m a.s.l., or 35 m higher in elevation than the EMS, which is situated in a relatively low area near a stream. The forest near this eddy covariance tower is broadly similar in species composition to the EMS site, but it is younger and shorter in stature. The site was cleared for pasture, but not deeply plowed or planted, in the 18th and19th centuries. Agriculture on the site was abandoned near the end of the 19th century. The forest within 200 to 300 m of the eddy covariance tower to the NW, W, SW, and S burned in an intense fire in 1957, which left few or no surviving trees.

openCC (other)Dec 2022View details →

Lake Mendota Carbon and Greenhouse Gas Measurements at North Temperate Lakes LTER 2016

This original dataset contains carbon and greenhouse gas (GHG) data collected in Lake Mendota during the summer of 2016. Data were collected between 15 April 2016 and 14 November 2016 on both Lake Mendota and its surrounding streams—four major inflows and the primary outflow of Lake Mendota. The dataset is comprised of four linked tables, corresponding to carbon and GHG measurements on Lake Mendota (lake_weekly_carbon_ghg), weekly physico-chemical sonde casts on Lake Mendota (lake_weekly_ysi), ebullition rate estimates on Lake Mendota (lake_weekly_ebullition), and carbon and physico-chemical data from the four major inflows and primary outflow of Lake Mendota (stream_weekly_carbon_ysi). These data were used to explore the relationship between organic carbon dynamics and greenhouse gas production on a eutrophic lake. From these data, it is possible to estimate daily oxygen, methane, and carbon dioxide flux on Lake Mendota during the study time period. Additional methods and applications of this data can be found in J.A. Harts Masters Thesis, University of Wisconsin-Madison Center for Limnology, May 2017.

openCC (other)Jan 2025View details →

Cascade Project at North Temperate Lakes LTER Core Data Carbon 1984 - 2023

Data on dissolved organic and inorganic carbon, particulate organic matter, partial pressure of CO2 and absorbance at 440nm. Samples were collected with a Van Dorn sampler. Organic carbon and absorbance samples were collected from the epilimnion, metalimnion, and hypolimnion. Inorganic samples were collected at depths corresponding to 100%, 50%, 25%, 10%, 5%, and 1% of surface irradiance, as well as one sample from the hypolimnion. Samples for the partial pressure of CO2 were collected from two meters above the lake surface (air) and just below the lake surface (water). Sampling frequency: varies; number of sites: 14

openCC (other)Jun 2025View details →

Water samples collected for dissolved inorganic carbon and nutrient analysis during tidal creek lateral exchange measurements approximately every 15 minutes from beginning of flood tide to the following low tide, Rowley, MA, PIE LTER.

Measurement of the lateral exchange of nutrients, sediment, and carbon in tidal creek systems draining predominantly low-elevation marsh dominated by Spartina alterniflora and high-elevation marsh dominated by Spartina patens located in Rowley, MA.

zenodo56/100

National contributions to climate change due to historical emissions of carbon dioxide, methane and nitrous oxide

A complete description of the dataset is given by <a href="http://doi.org/10.1038/s41597-023-02041-1">Jones et al. (2023)</a>. Key information is provided below. Background A dataset describing the global warming response to national emissions CO2, CH4 and N2O from fossil and land use sources during 1851-2021. National CO2 emissions data are collated from the Global Carbon Project (Andrew and Peters, 2024; Friedlingstein et al., 2024).  National CH4 and N2O emissions data are collated from PRIMAP-hist (HISTTP) (Gütschow et al., 2024). We construct a time series of cumulative CO2-equivalent emissions for each country, gas, and emissions source (fossil or land use). Emissions of CH4 and N2O emissions are related to cumulative CO2-equivalent emissions using the Global Warming Potential (GWP*) approach, with best-estimates of the coefficients taken from the IPCC AR6 (Forster et al., 2021). Warming in response to cumulative CO2-equivalent emissions is estimated using the transient climate response to cumulative carbon emissions (TCRE) approach, with best-estimate value of TCRE taken from the IPCC AR6 (Forster et al., 2021, Canadell et al., 2021). 'Warming' is specifically the change in global mean surface temperature (GMST). The data files provide emissions, cumulative emissions and the GMST response by country, gas (CO2, CH4, N2O or 3-GHG total) and source (fossil emissions, land use emissions or the total). Data records: overview The data records include three comma separated values (.csv) files as described below. All files are in ‘long’ format with one value provided in the Data column for each combination of the categorical variables Year, Country Name, Country ISO3 code, Gas, and Component columns. Component specifies fossil emissions, LULUCF emissions or total emissions of the gas. Gas specifies CO2, CH4, N2O or the three-gas total (labelled 3-GHG). Country ISO3 codes are specifically the unique ISO 3166-1 alpha-3 codes of each country. Data records: specifics Data are provided relative to 2 reference years (denoted ref_year below): 1850 and 1991. 1850 is a mutual first year of data spanning all input datasets. 1991 is relevant because the United Nations Framework Convention on Climate Change was operationalised in 1992. EMISSIONS_ANNUAL_{ref_year-20}-2023.csv: Data includes annual emissions of CO2 (Pg CO2 year-1), CH4 (Tg CH4 year-1) and N2O (Tg N2O year-1) during the period ref_year-20 to 2023. The Data column provides values for every combination of the categorical variables. Data are provided from ref_year-20 because these data are required to calculate GWP* for CH4. EMISSIONS_CUMULATIVE_CO2e100_{ref_year+1}-2023.csv: Data includes the cumulative CO2 equivalent emissions in units Pg CO2-e100 during the period ref_year+1 to 2023 (i.e. since the reference year). The Data column provides values for every combination of the categorical variables.  GMST_response_{ref_year+1}-2023.csv: Data includes the change in global mean surface temperature (GMST) due to emissions of the three gases in units °C during the period ref_year+1 to 2023 (i.e. since the reference year). The Data column provides values for every combination of the categorical variables.  Accompanying Code Code is available at: <a href="https://github.com/jonesmattw/National_Warming_Contributions">https://github.com/jonesmattw/National_Warming_Contributions</a> . The code requires Input.zip to run (see README at the GitHub link). Further info: Country Groupings We also provide estimates of the contributions of various country groupings as defined by the UNFCCC: <ul> <li>Annex I countries (number of countries, n = 42)</li> <li>Annex II countries (n = 23)</li> <li>economies in transition (EITs; n = 15)</li> <li>the least developed countries (LDCs; n = 47)</li> <li>the like-minded developing countries (LMDC; n = 24).</li> </ul> And other country groupings: <ul> <li>the organisation for economic co-operation and development (OECD; n = 38)</li> <li>the European Union (EU27 post-Brexit)</li> <li>the Brazil, South Africa, India and China (BASIC) group.</li> </ul> See COUNTRY_GROUPINGS.xlsx for the lists of countries in each group.

opencc-by-4.0Dec 2022View details →

openCC0Jun 2025View details →

Concentration of dissolved organic carbon in water samples taken from the Upper Clark Fork River (Montana, USA) during water years 2017 and 2018 (1 Oct 2016 - 30 Sep 2018)

These data were collected by the University of Montana and Montana State University to support the Upper Clark Fork River restoration monitoring project supported by the US NSF Long Term Research in Environmental Biology (LTREB) program. The original analytical intent for these data was to assess the response of river dissolved organic carbon to the floodplain restoration. Data are Aurora Total Organic Carbon combustion analyses of the concentration of organic carbon dissolved in filtered samples of well-mixed river thalweg water. Data are from the 2017 and 2018 water year (1 Oct 2016 to 30 Sep 2018). Data were collected on the Upper Clark Fork River (USGS HUC 17010201) at project sites distributed along the river from the vicinity of Anaconda to Missoula, Montana, USA.

openCC0Jul 2025View details →

Concentration of dissolved organic carbon in water samples taken from the Upper Clark Fork River (Montana, USA) during water year 2020 (1 Oct 2019 - 30 Sep 2020)

These data were collected to support monitoring of the Upper Clark Fork River restoration, and data collection was funded by the US NSF Long Term Research in Environmental Biology (LTREB) program and the US NSF EPSCoR funded Montana Consortium for Research on Environmental Water Systems. The LTREB monitoring project consists of monthly or bi-weekly water quality monitoring across a 200-km restoration gradient contaminated by historic mining practices to monitor inorganic phosphorus and nitrogen concentrations, biotic standing stocks, and heavy metal contamination. The original analytical intent for these data was to assess the response of river dissolved organic carbon to the floodplain restoration. Data are Aurora Total Organic Carbon combustion analyses of the concentration of organic carbon dissolved in filtered samples of well-mixed river thalweg water. Data are from the 2020 water year (1 Oct 2019 to 30 Sep 2020). Data were collected on the Upper Clark Fork River (USGS HUC 17010201) at project sites distributed along the river from the vicinity of Anaconda to Missoula, Montana, USA.

openCC (other)Jan 2026View details →

Time series of carbon dioxide and methane fluxes measured with eddy covariance for Falling Creek Reservoir in southwestern Virginia, USA during 2020-2025

We measured carbon dioxide and methane flux exchange with the atmosphere at the deepest site of Falling Creek Reservoir (Vinton, Virginia, USA) every 30 minutes from 04 April 2020 to 31 December 2025. Falling Creek Reservoir is a drinking water supply reservoir owned and managed by the Western Virginia Water Authority (WVWA) as a primary drinking water source. The dataset consists of micrometeorological and flux data collected using an eddy covariance system (LiCor Biosciences, Lincoln, Nebraska, USA) and analyzed with associated Eddy Pro software (Eddy Pro Version 7.0.6), including carbon dioxide, methane, and water vapor. All analysis scripts are included for data processing and quality assurance/quality control following best practices.

openCC (other)Jan 2026View details →

Time series of methane and carbon dioxide diffusive fluxes using an Ultraportable Greenhouse Gas Analyzer (UGGA) for Falling Creek Reservoir and Beaverdam Reservoir in southwestern Virginia, USA during 2018-2025

Diffusive fluxes of methane and carbon dioxide were measured using an Ultraportable Greenhouse Gas Analyzer (UGGA) at the surface of Falling Creek Reservoir (FCR) and Beaverdam Reservoir (BVR; Vinton, Virginia, USA). FCR and BVR are owned and operated by the Western Virginia Water Authority as drinking water sources for Roanoke, Virginia. The dataset consists of calculated diffusive fluxes of methane and carbon dioxide measured at the deepest site of the reservoir adjacent to the dam (2018–2025) and additional reservoir upstream sites in FCR (2018, 2023) and BVR (2022). In 2025, two littoral sites were measured at the northernmost wetland inflow to FCR. Measurements were collected approximately fortnightly in FCR throughout the summer stratified periods of 2018–2021 and 2023-2025, while measurements from BVR were only taken in 2018 and 2022-2024.

openCC0Aug 2023View details →

Multispectral absorbance and fluorescence analysis of dissolved organic carbon in water samples taken from the Upper Clark Fork River (Montana, USA) during water years 2017 and 2018 (1 Oct 2016 - 30 Sep 2018)

The Upper Clark Fork River (UCFR) Long Term Research in Environmental Biology (LTREB) umbrella monitoring project generating these data is conducted separately and complementarily to the 200-million-dollar (USD) superfund project for ecological restoration of the UCFR, associated tributaries, and head water streams including Silver Bow and Warm Springs Creeks. Restoration along the UCFR in western Montana includes removal of metal-laden floodplain soils, lowering of the floodplain to its original elevation, and re-vegetation of over 70 km of the river’s floodplain closest to contaminant sources. The UCFR LTREB project includes bi-weekly water quality monitoring across the first 200 km of the river and its major tributaries along a gradient of heavy metal contamination associated with historic mining. Monitoring includes inorganic phosphorus and nitrogen concentrations, biotic standing stocks, and dissolved and whole-water heavy metal concentrations. The monitoring program began in 2017 with funding likely to be extended through 2028. The original analytical intent for these data was to assess the response of river dissolved organic carbon to the floodplain restoration. Data are multispectral absorbance and fluorescence analyses of organic carbon dissolved in samples of well-mixed river thalweg water. Data include excitation-emission matrices, absorbance spectroscopy, as well as absorbance and fluorometric summary indices calculated at specific wavelengths of excitation and emission. Data are from the 2017 and 2018 water years (1 Oct 2016 to 30 Sep 2018). Data were collected on the Upper Clark Fork River (USGS HUC 17010201) at 13 project sites distributed along the river from the vicinity of Anaconda to Missoula, Montana, USA. These data are a correction of a previously published data product (doi:10.6073/pasta/6ba30f4ebb63175a4399c5d0aa6a8698). Inconsistencies between availability of EEMS data, absorbance data, and fluorometric summary metrics have been corrected. P

openCC (other)Mar 2025View details →

Reduced erosion augments soil carbon storage under cover crops

This dataset comprises field measurements of soil organic carbon erosion and soil organic carbon stock from 152 paired control and cover crop treatments, collected from 57 published studies worldwide. It also provides related information on the collected study sites, including climate (mean annual temperature and mean annual precipitation), geography (slope and altitude), soil properties (silt+clay and SOC concentration), and agricultural management (cover crop species, tillage intensity and experimental duration). Furthermore, it includes the estimated effect sizes of soil organic carbon erosion reduction induced by cover crops in agricultural lands at the global scale.