We determined soil microbial community composition and function in a field experiment in which plant communities of increasing species richness were exposed to factorial elevated CO2 and nitrogen (N) deposition treatments. Because elevated CO2 and N deposition increased plant productivity to a greater extent in more diverse plant assemblages, it is plausible that heterotrophic microbial communities would experience greater substrate availability, potentially increasing microbial activity, and accelerating soil carbon (C) and N cycling. We, therefore, hypothesized that the response of microbial communities to elevated CO2 and N deposition is contingent on the species richness of plant communities. Microbial community composition was determined by phospholipid fatty acid analysis, and function was measured using the activity of key extracellular enzymes involved in litter decomposition. Higher plant species richness, as a main effect, fostered greater microbial biomass, cellulolytic and chitinolytic capacity, as well as the abundance of saprophytic and arbuscular mycorrhizal (AM) fungi. Moreover, the effect of plant species richness on microbial communities was significantly modified by elevated CO2 and N deposition. For instance, microbial biomass and fungal abundance increased with greater species richness, but only under combinations of elevated CO2 and ambient N, or ambient CO2 and N deposition. Cellobiohydrolase activity increased with higher plant species richness, and this trend was amplified by elevated CO2. In most cases, the effect of plant species richness remained significant even after accounting for the influence of plant biomass. Taken together, our results demonstrate that plant species richness can directly regulate microbial activity and community composition, and that plant species richness is a significant determinant of microbial response to elevated CO2 and N deposition. The strong positive effect of plant species richness on cellulolytic capacity and microbial biomass indicate that the rates of soil C cycling may decline with decreasing plant species richness.
", "keywords": ["Extracellular Enzymes", "Complementary Resource Use", "Science", "Ecology and Evolutionary Biology", "Grassland Ecosystem", "Phospholipid Fatty Acid (PLFA)", "Global Change", "14. Life underwater", "complimentary resource use", "global change", "580", "2. Zero hunger", "Plant Diversity", "microbial biomass", "Geology and Earth Sciences", "grasslands", "Soil Fungi", "extracellular enzymes", "04 agricultural and veterinary sciences", "15. Life on land", "Microbial Biomass", "Soil C Cycling", "plant diversity", "13. Climate action", "0401 agriculture", " forestry", " and fisheries", "FACE (Free-air Carbon Dioxide Enrichment)"]}, "links": [{"href": "https://doi.org/10.1111/j.1365-2486.2007.01313.x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Change%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/j.1365-2486.2007.01313.x", "name": "item", "description": "10.1111/j.1365-2486.2007.01313.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/j.1365-2486.2007.01313.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2007-01-19T00:00:00Z"}}, {"id": "10.1046/j.1365-2486.2001.00388.x", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-25T16:17:59Z", "type": "Journal Article", "created": "2003-03-11", "title": "Chemistry And Decomposition Of Litter From Populus Tremuloides Michaux Grown At Elevated Atmospheric Co2 And Varying N Availability", "description": "SummaryIt has been hypothesized that greater production of total nonstructural carbohydrates (TNC) in foliage grown under elevated atmospheric carbon dioxide (CO2) will result in higher concentrations of defensive compounds in tree leaf litter, possibly leading to reduced rates of decomposition and nutrient cycling in forest ecosystems of the future. To evaluate the effects of elevated atmospheric CO2on litter chemistry and decomposition, we performed a 111 day laboratory incubation with leaf litter of trembling aspen (Populus tremuloidesMichaux) produced at 36\uffe2\uff80\uff83Pa and 56\uffe2\uff80\uff83Pa CO2and two levels of soil nitrogen (N) availability. Decomposition was quantified as microbially respired CO2and dissolved organic carbon (DOC) in soil solution, and concentrations of nonstructural carbohydrates, N, carbon (C), and condensed tannins were monitored throughout the incubation. Growth under elevated atmospheric CO2did not significantly affect initial litter concentrations of TNC, N, or condensed tannins. Rates of decomposition, measured as both microbially respired CO2and DOC did not differ between litter produced under ambient and elevated CO2. Total C lost from the samples was 38\uffe2\uff80\uff83mg\uffe2\uff80\uff83g\uffe2\uff88\uff921litter as respired CO2and 138\uffe2\uff80\uff83mg\uffe2\uff80\uff83g\uffe2\uff88\uff921litter as DOC, suggesting short\uffe2\uff80\uff90term pulses of dissolved C in soil solution are important components of the terrestrial C cycle. We conclude that litter chemistry and decomposition in trembling aspen are minimally affected by growth under higher concentrations of CO2.
", "keywords": ["Ecology and Evolutionary Biology", "carbohydrates", "Quaking aspen", "forest-soil", "litter-plant", "nitrogen", "nitrogen-", "Microlysimeter", "soil-chemistry", "cycling-", "populus-tremuloides", "Geology and Earth Sciences", "Soil Carbon", "Microbiology of soils", "Carbon cycle", "04 agricultural and veterinary sciences", "GLOBAL-ECOLOGY", "chemical-composition", "Organic-matter", "soil-solution", "nutrient-availability", "Tannin", "leaf-litter", "Science", "decomposition-", "Nutrient enrichment", "Carbohydrates", "carbohydrates-", "respiration-", "carbon-dioxide-enrichment", "Nitrogen in soil", "michigan-", "carbon sinks", "C", "Nutrient budget of forests", "Litter", "Populus tremuloides", "Global Change", "tannins-", "Decomposition", "forest-litter", "Foliage", "Carbon dioxide effects on forest litter", "Climatic changes", "15. Life on land", "carbon-nitrogen-ratio", "Forest litter decomposition", "N Ratio", "13. Climate action", "0401 agriculture", " forestry", " and fisheries", "microbial-activities", "nitrogen-content"]}, "links": [{"href": "https://doi.org/10.1046/j.1365-2486.2001.00388.x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Change%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1046/j.1365-2486.2001.00388.x", "name": "item", "description": "10.1046/j.1365-2486.2001.00388.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1046/j.1365-2486.2001.00388.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2001-01-01T00:00:00Z"}}, {"id": "10.1111/j.1365-2486.2004.00737.x", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-25T16:18:51Z", "type": "Journal Article", "created": "2004-12-24", "title": "Simulated Chronic No3\u2212Deposition Reduces Soil Respiration In Northern Hardwood Forests", "description": "AbstractChronic N additions to forest ecosystems can enhance soil N availability, potentially leading to reduced C allocation to root systems. This in turn could decrease soil CO2 efflux. We measured soil respiration during the first, fifth, sixth and eighth years of simulated atmospheric NO3\uffe2\uff88\uff92 deposition (3\uffe2\uff80\uff83g\uffe2\uff80\uff83N\uffe2\uff80\uff83m\uffe2\uff88\uff922\uffe2\uff80\uff83yr\uffe2\uff88\uff921) to four sugar maple\uffe2\uff80\uff90dominated northern hardwood forests in Michigan to assess these possibilities. During the first year, soil respiration rates were slightly, but not significantly, higher in the NO3\uffe2\uff88\uff92\uffe2\uff80\uff90amended plots. In all subsequent measurement years, soil respiration rates from NO3\uffe2\uff88\uff92\uffe2\uff80\uff90amended soils were significantly depressed. Soil temperature and soil matric potential were measured concurrently with soil respiration and used to develop regression relationships for predicting soil respiration rates. Estimates of growing season and annual soil CO2 efflux made using these relationships indicate that these C fluxes were depressed by 15% in the eighth year of chronic NO3\uffe2\uff88\uff92 additions. The decrease in soil respiration was not due to reduced C allocation to roots, as root respiration rates, root biomass, and root turnover were not significantly affected by N additions. Aboveground litter also was unchanged by the 8 years of treatment. Of the remaining potential causes for the decline in soil CO2 efflux, reduced microbial respiration appears to be the most likely possibility. Documented reductions in microbial biomass and the activities of extracellular enzymes used for litter degradation on the NO3\uffe2\uff88\uff92\uffe2\uff80\uff90amended plots are consistent with this explanation.
", "keywords": ["Nitrogen Fertilization", "Soil CO 2 Efflux", "Geology and Earth Sciences", "Science", "Atmospheric Nitrate Deposition", "Ecology and Evolutionary Biology", "Root Respiration", "0401 agriculture", " forestry", " and fisheries", "Temperature and Moisture Effects", "04 agricultural and veterinary sciences", "15. Life on land", "Root Biomass"]}, "links": [{"href": "https://doi.org/10.1111/j.1365-2486.2004.00737.x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Change%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/j.1365-2486.2004.00737.x", "name": "item", "description": "10.1111/j.1365-2486.2004.00737.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/j.1365-2486.2004.00737.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2004-05-07T00:00:00Z"}}, {"id": "10.1111/j.1365-2486.2005.01001.x", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-25T16:18:51Z", "type": "Journal Article", "created": "2005-08-19", "title": "Soil Organic Matter And Litter Chemistry Response To Experimental N Deposition In Northern Temperate Deciduous Forest Ecosystems", "description": "AbstractThe effects of atmospheric nitrogen (N) deposition on organic matter decomposition vary with the biochemical characteristics of plant litter. At the ecosystem\uffe2\uff80\uff90scale, net effects are difficult to predict because various soil organic matter (SOM) fractions may respond differentially. We investigated the relationship between SOM chemistry and microbial activity in three northern deciduous forest ecosystems that have been subjected to experimental N addition for 2 years. Extractable dissolved organic carbon (DOC), DOC aromaticity, C\uffe2\uff80\uff83:\uffe2\uff80\uff83N ratio, and functional group distribution, measured by Fourier transform infrared spectra (FTIR), were analyzed for litter and SOM. The largest biochemical changes were found in the sugar maple\uffe2\uff80\uff93basswood (SMBW) and black oak\uffe2\uff80\uff93white oak (BOWO) ecosystems. SMBW litter from the N addition treatment had less aromaticity, higher C\uffe2\uff80\uff83:\uffe2\uff80\uff83N ratios, and lower saturated carbon, lower carbonyl carbon, and higher carboxylates than controls; BOWO litter showed opposite trends, except for carbonyl and carboxylate contents. Litter from the sugar maple\uffe2\uff80\uff93red oak (SMRO) ecosystem had a lower C\uffe2\uff80\uff83:\uffe2\uff80\uff83N ratio, but no change in DOC aromaticity. For SOM, the C\uffe2\uff80\uff83:\uffe2\uff80\uff83N ratio increased with N addition in SMBW and SMRO ecosystems, but decreased in BOWO; N addition did not affect the aromaticity of DOC extracted from mineral soil. All ecosystems showed increases in extractable DOC from both litter and soil in response to N treatment. The biochemical changes are consistent with the divergent microbial responses observed in these systems. Extracellular oxidative enzyme activity has declined in the BOWO and SMRO ecosystems while activity in the SMBW ecosystem, particularly in the litter horizon, has increased. In all systems, enzyme activities associated with the hydrolysis and oxidation of polysaccharides have increased. At the ecosystem scale, the biochemical characteristics of the dominant litter appear to modulate the effects of N deposition on organic matter dynamics.
", "keywords": ["Litter Chemistry", "Geology and Earth Sciences", "13. Climate action", "Soil Organic Matter", "Science", "Ecology and Evolutionary Biology", "0401 agriculture", " forestry", " and fisheries", "Nitrogen Deposition", "04 agricultural and veterinary sciences", "15. Life on land", "Dissolved Organic Matter", "Extracellular Enzyme Activity"]}, "links": [{"href": "https://doi.org/10.1111/j.1365-2486.2005.01001.x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Change%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/j.1365-2486.2005.01001.x", "name": "item", "description": "10.1111/j.1365-2486.2005.01001.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/j.1365-2486.2005.01001.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2005-07-19T00:00:00Z"}}, {"id": "10.1111/j.1365-2486.2009.02058.x", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-25T16:18:54Z", "type": "Journal Article", "created": "2009-09-07", "title": "Maintenance Of Leaf N Controls The Photosynthetic Co2 Response Of Grassland Species Exposed To 9 Years Of Free-Air Co2 Enrichment", "description": "AbstractDetermining underlying physiological patterns governing plant productivity and diversity in grasslands are critical to evaluate species responses to future environmental conditions of elevated CO2 and nitrogen (N) deposition. In a 9\uffe2\uff80\uff90year experiment, N was added to monocultures of seven C3 grassland species exposed to elevated atmospheric CO2 (560\uffe2\uff80\uff83\uffce\uffbcmol\uffe2\uff80\uff83CO2\uffe2\uff80\uff83mol\uffe2\uff88\uff921) to evaluate how N addition affects CO2 responsiveness in species of contrasting functional groups. Functional groups differed in their responses to elevated CO2 and N treatments. Forb species exhibited strong down\uffe2\uff80\uff90regulation of leaf Nmass concentrations (\uffe2\uff88\uff9226%) and photosynthetic capacity (\uffe2\uff88\uff9228%) in response to elevated CO2, especially at high N supply, whereas C3 grasses did not. Hence, achieved photosynthetic performance was markedly enhanced for C3 grasses (+68%) in elevated CO2, but not significantly for forbs. Differences in access to soil resources between forbs and grasses may distinguish their responses to elevated CO2 and N addition. Forbs had lesser root biomass, a lower distribution of biomass to roots, and lower specific root length than grasses. Maintenance of leaf N, possibly through increased root foraging in this nutrient\uffe2\uff80\uff90poor grassland, was necessary to sustain stimulation of photosynthesis under long\uffe2\uff80\uff90term elevated CO2. Dilution of leaf N and associated photosynthetic down\uffe2\uff80\uff90regulation in forbs under elevated [CO2], relative to the C3 grasses, illustrates the potential for shifts in species composition and diversity in grassland ecosystems that have significant forb and grass components.
", "keywords": ["0106 biological sciences", "Nitrogen", "Science", "Ecology and Evolutionary Biology", "Poaceae C3 grass species", "carbon dioxide enrichment", "01 natural sciences", "nitrogen", "C 3 Grass Species", "FACE", "carbon cycle", "Species Functional Groups", "nitrogen cycle", "Free-air CO 2", "Carboxylation Rate", "Photosynthesis", "2. Zero hunger", "photosynthesis", "species diversity", "Geology and Earth Sciences", "carbon dioxide", "Carboxylation rate", "15. Life on land", "Species functional groups", "grasses", "Free-air CO2", "Keywords: angiosperm", "grassland"]}, "links": [{"href": "https://openresearch-repository.anu.edu.au/bitstream/1885/63064/5/Crous-etal_GCB2009-doi-online.pdf.jpg"}, {"href": "https://openresearch-repository.anu.edu.au/bitstream/1885/63064/7/01_Crous_Maintenance_of_leaf_N_controls_2009.pdf.jpg"}, {"href": "https://doi.org/10.1111/j.1365-2486.2009.02058.x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Change%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/j.1365-2486.2009.02058.x", "name": "item", "description": "10.1111/j.1365-2486.2009.02058.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/j.1365-2486.2009.02058.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2010-06-01T00:00:00Z"}}, {"id": "10.1111/j.1365-2486.2010.02376.x", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-25T16:18:55Z", "type": "Journal Article", "created": "2010-11-25", "title": "Fungal Community Composition And Function After Long-Term Exposure Of Northern Forests To Elevated Atmospheric Co2 And Tropospheric O-3", "description": "The long-term effects of rising atmospheric carbon dioxide (CO2) and tropospheric O3 concentrations on fungal communities in soil are not well understood. Here, we examine fungal community composition and the activities of cellobiohydrolase and N-acetylglucosaminidase (NAG) after 10 years of exposure to 1.5 times ambient levels of CO2 and O3 in aspen and aspen-birch forest ecosystems, and compare these results to earlier studies in the same long-term experiment.", "keywords": ["0106 biological sciences", "0301 basic medicine", "Elevated Ozone", "Geology and Earth Sciences", "Science", "Ecology and Evolutionary Biology", "Long\u2010Term", "Enzyme Activities", "Elevated Carbon Dioxide", "15. Life on land", "01 natural sciences", "03 medical and health sciences", "FACE", "13. Climate action", "Fungal Communities"]}, "links": [{"href": "https://doi.org/10.1111/j.1365-2486.2010.02376.x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Global%20Change%20Biology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/j.1365-2486.2010.02376.x", "name": "item", "description": "10.1111/j.1365-2486.2010.02376.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/j.1365-2486.2010.02376.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2011-01-05T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Geology+and+Earth+Sciences&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=Geology+and+Earth+Sciences&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=Geology+and+Earth+Sciences&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Geology+and+Earth+Sciences&offset=6", "hreflang": "en-US"}], "numberMatched": 6, "numberReturned": 6, "distributedFeatures": [], "timeStamp": "2026-07-26T09:24:12.469108Z"}