Rising atmospheric carbon dioxide (CO2) could alter the carbon (C) and nitrogen (N) content of ecosystems, yet the magnitude of these effects are not well known. We examined C and N budgets of a subtropical woodland after 11\uffc2\uffa0yr of exposure to elevated CO2.
We used open\uffe2\uff80\uff90top chambers to manipulate CO2 during regrowth after fire, and measured C, N and tracer 15N in ecosystem components throughout the experiment.
Elevated CO2 increased plant C and tended to increase plant N but did not significantly increase whole\uffe2\uff80\uff90system C or N. Elevated CO2 increased soil microbial activity and labile soil C, but more slowly cycling soil C pools tended to decline. Recovery of a long\uffe2\uff80\uff90term 15N tracer indicated that CO2 exposure increased N losses and altered N distribution, with no effect on N inputs.
Increased plant C accrual was accompanied by higher soil microbial activity and increased C losses from soil, yielding no statistically detectable effect of elevated CO2 on net ecosystem C uptake. These findings challenge the treatment of terrestrial ecosystems responses to elevated CO2 in current biogeochemical models, where the effect of elevated CO2 on ecosystem C balance is described as enhanced photosynthesis and plant growth with decomposition as a first\uffe2\uff80\uff90order response.
", "keywords": ["Soil organic matter", "Long term experiment", "Elevated atmospheric CO2", "Florida scrub oak", "Scrub oak", "Research", "Plant Sciences", "Aboveground biomass", "Plant Biology", "Microbial communities", "04 agricultural and veterinary sciences", "Carbon Cycling", "15. Life on land", "Forest productivity", "Soil carbon", "Rhizosphere processes", "Terrestrial ecosystems", "Dioxide enrichment", "13. Climate action", "0401 agriculture", " forestry", " and fisheries", "Elevated CO2", "Climate feedbacks", "Global change", "Subtropical woodland", "Nitrogen cycling"]}, "links": [{"href": "https://digitalcommons.odu.edu/context/biology_fac_pubs/article/1264/viewcontent/Day2013CumulativeResponseofEcosystemCarbonandNitrogenOCR.pdf"}, {"href": "https://doi.org/10.1111/nph.12333"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/New%20Phytologist", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/nph.12333", "name": "item", "description": "10.1111/nph.12333", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/nph.12333"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2013-05-30T00:00:00Z"}}, {"id": "10.5061/dryad.040jp22", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:21:18Z", "type": "Dataset", "title": "Data from: Plant economic strategies of grassland species control soil carbon dynamics through rhizodeposition", "description": "unspecified1. The plant economics spectrum is increasingly recognized as a major determinant of plant species effects on terrestrial ecosystem functioning related to carbon cycling. However, the role of plant economic strategies in the effects of living root activity on soil organic carbon (SOC) dynamics through rhizodeposition remains unexplored, despite SOC being the largest terrestrial carbon pool. 2. Using a continuous 13C-labeling method allowing partitioning of plant and soil sources to carbon fluxes and pools, we studied here the linkages between plant economic strategies and SOC cycling processes in a \u2018common garden\u2019 greenhouse experiment. It includes a panel of 12 grassland species selected along a gradient of economic traits and belonging to three functionnal groups (C3 grasses, forbs and legumes). 3. All species induced an acceleration of native SOC mineralization but this rhizosphere priming effect (RPE) substantially differed across species and varied eleven-fold by the end of the experiment (from +26 to +295 % relative to unplanted soil). Interspecific variation in RPE was primarily linked to plant photosynthetic activity associated to species economic strategies of light and CO2 resource acquisition and processing. Fast-growing acquisitive species, such as legumes, featured large RPE, in relation with their high canopy photosynthesis coupled to high leaf photosynthetic capacity and large net primary productivity allocated aboveground. This large RPE was further associated with high root metabolic activity, rhizodeposition and soil microbial activity. In contrast, fine-root growth and economic traits related to soil resource foraging ability were poor predictors of RPE. 4. The formation of new root-derived SOC varied nine-fold across species and was similarly positively related to the net primary productivity allocated aboveground. Fast-growing acquisitive species with a high photosynthetic activity induced a disproportionately large RPE relative to SOC formation. 5. Synthesis. Overall, our study demonstrates that rhizodeposition is a major mechanism through which plant economic strategies of grassland species control soil carbon dynamics. Acquisitive versus conservative species were associated with high versus low rates of photosynthesis and rhizodeposition, in turn leading to fast versus slow SOC turnover. This emphasizes the importance of considering rhizosphere processes for understanding plant species effects on soil biogeochemistry.", "keywords": ["2. Zero hunger", "Chamerion angustifolium", "Nardus stricta", "plant-soil (below-ground) interactions", "Festuca rubra", "Melilotus albus", "15. Life on land", "Rumex acetosa", "rhizosphere processes", "plant economics spectrum", "leaf and root traits", "Vicia cracca", "Lotus corniculatus", "Plantago lanceolata", "Taraxacum officinale", "Poa trivialis", "Photosynthesis", "Anthoxanthum odoratum", "Rhizosphere priming effect"], "contacts": [{"organization": "Henneron, Ludovic, Cros, Camille, Picon-Cochard, Catherine, Rahimian, Vida, Fontaine, S\u00e9bastien,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5061/dryad.040jp22"}, {"rel": "self", "type": "application/geo+json", "title": "10.5061/dryad.040jp22", "name": "item", "description": "10.5061/dryad.040jp22", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5061/dryad.040jp22"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-12-01T00:00:00Z"}}, {"id": "10.5061/dryad.hhmgqnkk9", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:21:27Z", "type": "Dataset", "title": "Visualization and quantification of carbon 'rusty sink' by rice root iron plaque: mechanisms, functions, and global implications", "description": "Paddies contain 78% higher organic carbon (C) stocks than adjacent upland soils, and iron (Fe) plaque formation on rice roots is one of the mechanisms that traps C. The process sequence, extent and global relevance of this C stabilization mechanism under oxic/anoxic conditions remains unclear. We quantified and localized the contribution of Fe plaque to C stabilization in a microoxic area (rice rhizosphere) and evaluated the role of this C trap toward global C sequestration in paddy soils. Visualization and localization of pH by imaging with planar optodes, enzyme activities by zymography, and root exudation by 14C imaging, as well as upscale modeling enabled linkage of three groups of rhizosphere processes that are responsible for C stabilization from the micro- (root) to the macro- (ecosystem) level. The 14C activity in soil (reflecting stabilization of rhizodeposits) with Fe2+ addition was 1.4\u22121.5 times higher than that in the control and phosphate addition soils. Perfect co-localization of the hotspots of \u03b2-glucosidase activity (by zymography) with exudation showed that labile C and high enzyme activities were localized within Fe plaques. Fe2+ addition to soil and its microbial oxidation to Fe3+ by radial oxygen release from rice roots increased Fe plaque (Fe3+) formation by 1.7\u22122.5 times. The C trapped by Fe plaque was 1.1 times higher after Fe2+ addition. Therefore, Fe plaque formed from amorphous and complex Fe on root surface act as a \u201crusty sink\u201d for C. Upscaling by model revealed the global significance of C preservation within Fe3+ complexes in paddy soils. Considering the area of coverage of paddy soils globally, radial oxygen loss from roots and bacterial Fe oxidation may trap up to 130 Mg C in Fe plaques per rice season. This represents an important annual surplus of new and stable C to the existing C pool under long-term rice cropping.", "keywords": ["2. Zero hunger", "Carbon sequestration", "Fe-oxidizing and Fe-reducing bacteria", "FOS: Agricultural sciences", "15. Life on land", "rhizosphere processes", "Iron plaque", "enzyme activity", "Fluctuating redox conditions"], "contacts": [{"organization": "Wei, Liang", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5061/dryad.hhmgqnkk9"}, {"rel": "self", "type": "application/geo+json", "title": "10.5061/dryad.hhmgqnkk9", "name": "item", "description": "10.5061/dryad.hhmgqnkk9", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5061/dryad.hhmgqnkk9"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-08-03T00:00:00Z"}}, {"id": "11353/10.2156897", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-26T16:24:55Z", "type": "Journal Article", "created": "2025-02-05", "title": "Preferential use of organic acids over sugars by soil microbes in simulated root exudation", "description": "Sugars and organic acids, primary components in plant root exudates, are thought to enhance microbial decomposition of organic matter in the rhizosphere. However, their specific impacts on microbial activity and nutrient mobilisation remain poorly understood. Here, we simulated passive root exudation to investigate the distinct effects of sugars and organic acids on microbial metabolism in the rhizosphere. We released 13C-labelled sugars and/or organic acids via reverse microdialysis into intact meadow and forest soils over 6-h. We measured substrate-induced microbial respiration, soil organic matter mineralization, metabolite concentrations, and substrate incorporation into lipid-derived fatty acids. Our results reveal a pronounced microbial preference for organic acids over sugars, with organic acids being removed faster from the exudation spot and preferentially respired by microbes. Unlike sugars, organic acids increased concentrations of microbial metabolic byproducts and cations (K, Ca, Mg) near the exudation spot. Our results challenge the prevailing assumption that sugars are the most readily available and rapidly consumed substrates for soil microbes. Microbial preference for organic acids indicates a trade-off between rapid biomass growth and ATP yield. Our findings underscore the significant role of exudate composition in influencing microbial dynamics and nutrient availability, and emphasize the importance of biotic and abiotic feedback mechanisms in the rhizosphere in regulating root exudation.", "keywords": ["106022 Mikrobiologie", "Short-chain fatty acids", "Microbial metabolites", "Artificial root exudate", "Cation mobilization", "Growth yield trade-off", "106022 Microbiology", "Biogeochemical feedback", "Rhizosphere processes"]}, "links": [{"href": "https://doi.org/11353/10.2156897"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Soil%20Biology%20and%20Biochemistry", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "11353/10.2156897", "name": "item", "description": "11353/10.2156897", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/11353/10.2156897"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2025-04-01T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Rhizosphere+processes&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Rhizosphere+processes&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Rhizosphere+processes&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Rhizosphere+processes&offset=4", "hreflang": "en-US"}], "numberMatched": 4, "numberReturned": 4, "distributedFeatures": [], "timeStamp": "2026-07-27T04:00:12.127626Z"}