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opencc-zeroOct 2020View details →

Elevated atmospheric concentrations of CO2 increase endogenous immune function in a specialist herbivore

1. Animals rely on a balance of endogenous and exogenous sources of immunity to mitigate parasite attack. Understanding how environmental context affects that balance is increasingly urgent under rapid environmental change. In herbivores, immunity is determined, in part, by phytochemistry which is plastic in response to environmental conditions. Monarch butterflies, Danaus plexippus, consistently experience infection by a virulent parasite, Ophryocystis elektroscirrha, and some medicinal milkweed (Asclepias) species, with high concentrations of toxic steroids (cardenolides), provide a potent source of exogenous immunity. 2. We investigated plant-mediated influences of elevated CO2 (eCO2) on endogenous immune responses of monarch larvae to infection by O. elektroscirrha. Recently, transcriptomics have revealed that infection by O. elektroscirrha does not alter monarch immune gene regulation in larvae, corroborating that monarchs rely more on exogenous than endogenous immunity. However, monarchs feeding on medicinal milkweed grown under eCO2 lose tolerance to the parasite, associated with changes in phytochemistry. Whether changes in milkweed phytochemistry induced by eCO2 alter the balance between exogenous and endogenous sources of immunity remains unknown. 3. We fed monarchs two species of milkweed; A. curassavica (medicinal) and A. incarnata (non-medicinal) grown under ambient CO2 (aCO2) or eCO2. We then measured endogenous immune responses (phenoloxidase activity, hemocyte concentration, and melanization strength), along with foliar chemistry, to assess mechanisms of monarch immunity under future atmospheric conditions. 4. The melanization response of late-instar larvae was reduced on medicinal milkweed in comparison to non-medicinal milkweed. Moreover, the endogenous immune responses of early-instar larvae to infection by O. elektroscirrha were generally lower in larvae reared on foliage from aCO2 plants and higher in larvae reared on foliage from eCO2 plants. When grown under eCO2, milkweed plants exhibited lower cardenolide concentrations, lower phytochemical diversity, and lower nutritional quality (higher C:N ratios). Together, these results suggest that the loss of exogenous immunity from foliage under eCO2 results in increased endogenous immune function. 5. Animal populations face multiple threats induced by anthropogenic environmental change. Our results suggest that shifts in the balance between exogenous and endogenous sources of immunity to parasite attack may represent an underappreciated consequence of environmental change.

zenodo36/100

Simulated atmospheric CO2 concentration at Point Barrow, Alaska

This dataset is provided in order to enable the reproduction of findings from a series of experiments with the CASA-TOMCAT model setup (Chipperfield, 2006).  The Carnegie Ames Stanford Approach (CASA) is a land-surface model that was used to produce fluxes of net ecosystem exchange (NEE) and fires. Our simulations held various input parameters constant in CASA (described below). We then forced the TOMCAT atmospheric chemistry model with these data to produce an estimate of atmospheric CO2 at the Barrow Observatory in Alaska. Further information on the details of the model setup is described in the 'Model_setup.txt' file. Enclosed in this directory are the simulated CO2 at Barrow observatory, Alaska (71.3N, 156.6E) for a number of experiments which are described below. Half of the text files have variable meteorology and are described as 'atmos_vary' in the title, the remaining half have constant (periodical) meteorology, in which atmospheric transport is retained at 1992 values (and described as 'atmos_const'). Within each file is the time and date of each measurement of atmospheric CO2 in ppm. In order to obtain the required simulated atmospheric value, add the background, ocean, and fossil fuel (FF) tracer values to the relevant NEE and fire value from the simulation of interest. The simulations are as follows (with their abbreviation given in parentheses):  Constant, periodical temperature scalar (temp) Constant, periodical temperature and moisture scalars (temppre) Constant, periodical fraction of photosynthetically active radiation (fpar) Constant, periodical solar radiation (solrad) All the above variables held constant, periodical (all) Control run in which everything varies (ctrl)

opencc-by-4.0Jan 2021View details →

zenodo36/100

High-spatiotemporal resolution mapping of spatiotemporally continuous atmospheric CO2 concentrations over the global continent

This dataset contains global continental-scale carbon dioxide inversion results for four periods in 2015 with a spatial resolution of 0.01°.

opencc-by-4.0Jan 2022View details →

zenodo36/100

Data for "Impact of prior terrestrial carbon flux on atmospheric CO2 concentration simulation"

Data for "Impact of prior terrestrial carbon flux on atmospheric CO2 concentration simulation"

opencc-by-4.0Jul 2021View details →

opencc-zeroDec 2022View details →

Isotopic evidence for increased carbon and nitrogen exchanges between peatland plants and their symbiotic microbes with rising atmospheric CO2 concentrations since 15000 cal. yr BP

Whether nitrogen (N) availability will limit plant growth and removal of atmospheric CO2 this century is controversial. Studies have suggested that N could progressively limit plant growth, as trees and soils accumulate N in slowly cycling biomass pools in response to increases in carbon sequestration. However, a question remains over the longer-term (decadal to century) feedbacks between climate, CO2 and plant N uptake. The symbiosis between plants and microbes can help plants with mycorrhizal N uptake or biological N2 fixation – the pathway through which N can be rapidly brought into ecosystems and thereby partially or completely alleviate N limitation on plant productivity. Here we present results for plant N isotope composition (δ15N) in a peat core that dates to 15000 cal. yr BP to ascertain ecosystem-level N cycling responses to rising atmospheric CO2 concentrations in the past. We found that an increase in atmospheric CO2 concentration happened with a decrease in δ15N values of both Sphagnum moss and Ericaceae over this time period when constrained for climatic factors. A modern experiment demonstrated that δ15N of Sphagnum mosses decreased with increasing N2 fixation rates. These findings suggested that N2 fixation in Sphagnum moss by symbiosis with cyanobacteria and N uptake in Ericaceae by symbiosis with mycorrhizal fungi both likely increased with rising atmospheric CO2 concentrations, highlighting a longer-term feedback mechanism whereby N constraints on terrestrial carbon storage can be overcome.

publicOct 2020View details →

Elevated atmospheric concentrations of CO2 increase endogenous immune function in a specialist herbivore

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publicDec 2022View details →

Isotopic evidence for increased carbon and nitrogen exchanges between peatland plants and their symbiotic microbes with rising atmospheric CO2 concentrations since 15000 cal. yr BP

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dryad32/100

Data from: Rising atmospheric CO2 is reducing the protein concentration of a floral pollen source essential for North American bees

At present, there is substantive evidence that the nutritional content of agriculturally important food crops will decrease in response to rising levels of atmospheric carbon dioxide, Ca. However, whether Ca-induced declines in nutritional quality are also occurring for pollinator food sources is unknown. Flowering late in the season, goldenrod (Solidago spp.) pollen is a widely available autumnal food source commonly acknowledged by apiarists to be essential to native bee (e.g. Bombus spp.) and honeybee (Apis mellifera) health and winter survival. Using floral collections obtained from the Smithsonian Natural History Museum, we quantified Ca-induced temporal changes in pollen protein concentration of Canada goldenrod (Solidago canadensis), the most widespread Solidago taxon, from hundreds of samples collected throughout the USA and southern Canada over the period 1842–2014 (i.e. a Ca from approx. 280 to 398 ppm). In addition, we conducted a 2 year in situ trial of S. canadensis populations grown along a continuous Ca gradient from approximately 280 to 500 ppm. The historical data indicated a strong significant correlation between recent increases in Ca and reductions in pollen protein concentration (r2 = 0.81). Experimental data confirmed this decrease in pollen protein concentration, and indicated that it would be ongoing as Ca continues to rise in the near term, i.e. to 500 ppm (r2 = 0.88). While additional data are needed to quantify the subsequent effects of reduced protein concentration for Canada goldenrod on bee health and population stability, these results are the first to indicate that increasing Ca can reduce protein content of a floral pollen source widely used by North American bees.

opencc-zeroDec 2015View details →

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Data from: Rising atmospheric CO2 is reducing the protein concentration of a floral pollen source essential for North American bees

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publicMar 2017View details →

dryad28/100

Water availability drives fine root dynamics in a Eucalyptus woodland under elevated atmospheric CO2 concentration

Fine roots are a key component of carbon and nutrient dynamics in forest ecosystems. Rising atmospheric [CO2] (eCO2) is likely to alter the production and activity of fine roots, with important consequences for forest carbon storage. Yet empirical evidence of the role of eCO2 in driving root dynamics in low-nutrient forested ecosystems is limited, particularly for grassy woodlands, an ecosystem type of global importance. We sampled fine roots across seasons over a two-year period to examine the effects of eCO2 on their biomass, production, turnover and functional traits in a native mature grassy Eucalyptus woodland in eastern Australia (EucFACE). Fine root biomass, production and turnover varied greatly through time, increasing as soil water content declined. Despite a lack of persistent effects of eCO2 on fine root biomass, production or turnover across the two-year sampling period, we found enhanced production pulses under eCO2 between 10-30 cm soil depth. These eCO2-driven production pulses were associated with large changes in abiotic conditions. In addition, eCO2 led to greater carbon and phosphorus concentrations in fine roots and increased root diameter, but no detectable effects on other morphological traits. Synthesis. We found minor quantitative effects of eCO2 on fine root biomass dynamics that were largely driven by temporal variations in soil water availability. Our results suggest that in this mature grassy woodland, and perhaps also in other similar forested ecosystem types characterized by low phosphorus content in the soil, eCO2 effects are small and transient. This suggests limited belowground fine root productivity responses to rising atmospheric CO2 concentrations and, thus, perhaps also a limited ability of these systems to mitigate climate change through belowground mechanisms.

opencc-zeroAug 2020View details →

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Water availability drives fine root dynamics in a Eucalyptus woodland under elevated atmospheric CO2 concentration

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publicAug 2020View details →

CARVE: L2 Atmospheric CO2, CO, and CH4 Concentrations, CARVE Tower, Alaska, 2011-2015

This data set provides atmospheric methane (CH4), carbon dioxide (CO2), and carbon monoxide (CO) dry air mole fractions and water vapor mole fractions (H2O) from continuous in situ measurements at the CARVE flux tower in Fox, Alaska between October 2011 and May 2015 for the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE). Air was drawn from three different heights above the base of the tower (31.7 m, 17.1 m, and 4.9 m) and analyzed using a Picarro cavity ring-down spectrometer (CRDS). Measurements of ambient and sonic temperature, vertical and horizontal velocity, and atmospheric pressure are also included in the data set.

CARVE: L2 Atmospheric CO2, CO and CH4 Concentrations, Harvard CRDS, Alaska, 2012-2014

This data set provides atmospheric carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) concentrations from airborne campaigns over the Alaskan and Canadian arctic for the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE). The data were collected in situ using a four-species cavity ring-down spectrometer system (CRDS; Picarro Inc.) provided by Harvard University and are presented at 5-second intervals throughout each flight. The Harvard CRDS instrument only collected data in 2012-2014; no Harvard data are available for year 2015. Aircraft latitude, longitude, and altitude are also provided. CARVE flight campaigns took place from 2012 to 2015 between the months of March and November to enable investigation of both seasonal and inter-annual variability in atmospheric gas content. The measurements included in this data set are crucial for understanding changes in Arctic carbon cycling and the potential threats posed by thawing of Arctic permafrost.

ACT-America: L2 In Situ Atmospheric CO2, CO, CH4, and O3 Concentrations, Eastern USA

This dataset provides atmospheric carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), water vapor (H2O), and ozone (O3) concentrations collected during airborne campaigns conducted by the Atmospheric Carbon and Transport-America (ACT-America) project. ACT-America's mission spanned 4 years and included five 6-week airborne campaigns covering all 4 seasons and 3 regions of the central and eastern United States. This dataset provides results from all five campaigns, including Summer 2016, Winter 2017, Fall 2017, Spring 2018, and Summer 2019. Two instrumented aircraft platforms, the NASA Langley Beechcraft B200 King Air and the NASA Goddard Space Flight Center's C-130H Hercules, were used to collect high-quality in situ measurements across a variety of continental surfaces and atmospheric conditions. CO2, CO, CH4, and H2O were collected with an infrared cavity ring-down spectrometer system (CRDS; Picarro Inc.). Ozone data were collected with a dual beam differential UV absorption ozone monitor (Model 205; 2B Technologies). Both aircraft hosted identical arrays of in situ sensors. Complete aircraft flight information including, but not limited to, latitude, longitude, altitude, and meteorological conditions are also provided.

CARVE: CH4, CO2, and CO Atmospheric Concentrations, CARVE Tower, Alaska, 2012-2014

This data set provides hourly atmospheric concentrations of methane (CH4), carbon dioxide (CO2), and carbon monoxide (CO) as mole fractions, from January 2012 to December 2014 measured at the CARVE flux tower in Fox, Alaska (17 km north of Fairbanks) as part of NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE). High-resolution meteorological fields from the Polar Weather Research and Forecasting (WRF) model coupled with the Stochastic Time-Inverted Lagrangian Transport model (WRF- STILT), along with the Polar Vegetation Photosynthesis and Respiration Model (PolarVPRM) were used to determine the influence region of the tower site and investigate the inter-annual and seasonal variability of regional fluxes of CO2 and CH4 in boreal Alaska using the tower observations. Modeled estimates of CH4, CO2, and CO background concentrations are provided. The WRF-STILT model "footprints" for the CARVE tower are provided with this data set.

CARVE: L2 Merged Atmospheric CO2, CO, O3 and CH4 Concentrations, Alaska, 2012-2015

This data set provides atmospheric carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), ozone (O3), and water vapor (H2O) concentrations from airborne campaigns over the Alaskan and Canadian arctic for the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE). These data are merged and gap-filled outputs from two different cavity ring-down spectrometers (CRDS; Picarro Inc.) flown aboard the CARVE aircraft and are presented at 5-second intervals throughout each flight. Aircraft latitude, longitude, and altitude are also provided. Flight campaigns took place from 2012 to 2015 between the months of March and November to enable investigation of both seasonal and inter-annual variability in atmospheric gas content. The measurements included in this data set are crucial for understanding changes in Arctic carbon cycling and the potential threats posed by thawing of Arctic permafrost.

NACP MCI: Tower Atmospheric CO2 Concentrations, Upper Midwest Region, USA, 2007-2009

This data set provides high precision and high accuracy atmospheric CO2 data from seven instrumented communication towers located in the U.S. Upper Midwest. The overall sampling period was from January 2007 through December 2009 although actual sampling dates vary within this time period for individual towers and sampling heights above ground level. The measurements were obtained in support of the North American Carbon Program (NACP) Mid-Continent Intensive (MCI) campaign.The sampling network included: the five Ring 2 towers (Centerville (Iowa), Galesville (Wisconsin), Kewanee (Illinois), Mead (Nebraska), and Round Lake (Minnesota)) deployed and operated by PSU; the Missouri Ozarks (Missouri) co-located AmeriFlux site (PSU/Oak Ridge National Laboratory (ORNL)); and the Rosemount (Minnesota) tall tower trace gas observatory (University of Minnesota, Rosemount Research and Outreach Center (RROC)). Hourly CO2 dry mole fractions (in ppm) were averaged from measurements made at different above-ground levels on the towers and are reported in Coordinated Universal Time (UTC). For the five Ring 2 sites, daily daytime average CO2 dry mole fractions were also calculated, from hourly values between 12:00-17:00 local standard time and reported in UTC. There are seven compressed (.zip) data files and one comma-separated (.csv) file with this data set. Data quality flags are provided in each file.

CARVE: L2 Atmospheric CO2, CO and CH4 Concentrations, NOAA CRDS, Alaska, 2012-2015

This data set provides atmospheric carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and water vapor (H2O) concentrations from airborne campaigns over the Alaskan and Canadian arctic for the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE). The data were collected in situ using a cavity ring-down spectrometer (CRDS; Picarro Inc.) and are presented at 2-second intervals throughout each flight. Aircraft latitude, longitude, and altitude are also provided. Flight campaigns took place from 2012 to 2015 between the months of March and November to enable investigation of both seasonal and inter-annual variability in atmospheric gas content. The measurements included in this data set are crucial for understanding changes in Arctic carbon cycling and the potential threats posed by thawing of Arctic permafrost.

ISLSCP II Globalview: Atmospheric CO2 Concentrations

The GlobalView Carbon Dioxide (CO2) data product contains synchronized and smoothed time series of atmospheric CO2 concentrations at selected sites that were created using the data extension and integration techniques described by Masarie and Tans, (1995). The information needed to derive this time series is also in this data set, along with extensive documentation. The longest period of coverage is from 1979 to 2001 with some sites having longer or shorter temporal coverage. Note that the GlobalView CO2 data products are derived from measurements but contain no actual data. To facilitate heterogeneous CO2 data use in carbon cycle modeling studies, the measurements have been processed (smoothed, interpolated, and extrapolated) resulting in extended records that are evenly incremented in time. There are 92 files with this data set which includes 89 *.zip data files. The other three files include 2 files with site information, one comma-delimited ASCII file (.csv), and one .dat file, and one .dat file which is a single reference marine boundary layer matrix file which contains CO2 mixing ratios as a function of time and sine of latitude and is a by-product of the data extension procedure.