{"type": "FeatureCollection", "features": [{"id": "10.1007/s10533-021-00838-z", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:14:51Z", "type": "Journal Article", "created": "2021-08-27", "title": "Soil organic matter turnover rates increase to match increased inputs in grazed grasslands", "description": "Abstract

Managed grasslands have the potential to store carbon (C) and partially mitigate climate change. However, it remains difficult to predict potential C storage under a given soil or management practice. To study C storage dynamics due to long-term (1952\uffe2\uff80\uff932009) phosphorus (P) fertilizer and irrigation treatments in New Zealand grasslands, we measured radiocarbon (14C) in archived soil along with observed changes in C stocks to constrain a compartmental soil model. Productivity increases from P application and irrigation in these trials resulted in very similar C accumulation rates between 1959 and 2009. The \uffe2\uff88\uff8614C changes over the same time period were similar in plots that were both irrigated and fertilized, and only differed in a non-irrigated fertilized plot. Model results indicated that decomposition rates of fast cycling C (0.1 to 0.2\uffc2\uffa0year\uffe2\uff88\uff921) increased to nearly offset increases in inputs. With increasing P fertilization, decomposition rates also increased in the slow pool (0.005 to 0.008\uffc2\uffa0year\uffe2\uff88\uff921). Our findings show sustained, significant (i.e. greater than 4 per mille) increases in C stocks regardless of treatment or inputs. As the majority of fresh inputs remain in the soil for less than 10\uffc2\uffa0years, these long term increases reflect dynamics of the slow pool. Additionally, frequent irrigation was associated with reduced stocks and increased decomposition of fresh plant material. Rates of C gain and decay highlight trade-offs between productivity, nutrient availability, and soil C sequestration as a climate change mitigation strategy.Global warming is accompanied by increasing water stress across much of our planet. We studied soil biological processes and changes in soil organic carbon (SOC) storage in 30 Hungarian oak forest sites in the Carpathian Basin along a climatic gradient (mean annual temperature (MAT) 9.6\uffe2\uff80\uff9312.1\uffc2\uffa0\uffc2\uffb0C, mean annual precipitation (MAP) 545\uffe2\uff80\uff93725\uffc2\uffa0mm) but on similar gently sloped hillsides where the parent materials are loess and weathered dust inputs dating from the end of the ice age. The purpose of this research was to understand how a drying climate, predicted for this region, might regulate long-term SOC sequestration. To examine the effects of decreasing water availability, we compared soil parameters and processes in three categories of forest that represented the moisture extremes along our gradient and that were defined using a broken-stick regression model. Soil biological activity was significantly lower in the driest (\uffe2\uff80\uff9cdry\uffe2\uff80\uff9d) forests, which had more than double the SOC concentration in the upper 30\uffc2\uffa0cm layer (3.28\uffc2\uffa0g C/100\uffc2\uffa0g soil\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.11 SE) compared to soils of the wettest (\uffe2\uff80\uff9chumid\uffe2\uff80\uff9d) forests (1.32\uffc2\uffa0g C/100\uffc2\uffa0g soil\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.09 SE), despite the fact that annual surface litter production in humid forests was\uffe2\uff80\uff89~\uffe2\uff80\uff8937% higher than in dry forests. A two-pool SOM model constrained to fit radiocarbon data indicates that turnover times for fast and slow pools are about half as long in the humid soil compared to the dry soil, and humid soils transfer C twice as efficiently from fast to slow pools. Enzyme activity and fungal biomass data also imply shorter turnover times associated with faster degradation processes in the soils of humid forests. Thermogravimetry studies suggest that more chemically recalcitrant compounds are accumulating in the soils of dry forests. Taken together, our results suggest that the predicted climate drying in this region might increase SOC storage in Central European mesic deciduous forests even as litter production decreases.

", "keywords": ["2. Zero hunger", "SOM", " C sequestration", " Soil enzyme activity", " Radiocarbon", " Climosequence", " Decomposition", " Climate change", " Forest soil", " Soil biology", "13. Climate action", "0401 agriculture", " forestry", " and fisheries", "04 agricultural and veterinary sciences", "15. Life on land"], "contacts": [{"organization": "Istvan Fekete, Imre Berki, Kate Lajtha, Susan Trumbore, Ornella Francioso, Paola Gioacchini, Daniela Montecchio, Gabor Varb\u0131ro \u0301, Aron Beni, Marianna Makadi, Ibolya Demeter, Balazs Madarasz, Katalin Juhos, Zsolt Kotroczo,", "roles": ["creator"]}]}, "links": [{"href": "https://cris.unibo.it/bitstream/11585/795544/1/Fekete2021_Article_HowWillADrierClimateChangeCarb.pdf"}, {"href": "http://link.springer.com/content/pdf/10.1007/s10533-020-00728-w.pdf"}, {"href": "https://doi.org/10.1007/s10533-020-00728-w"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Biogeochemistry", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s10533-020-00728-w", "name": "item", "description": "10.1007/s10533-020-00728-w", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s10533-020-00728-w"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-11-19T00:00:00Z"}}, {"id": "10.1029/2020gb006672", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:18:30Z", "type": "Journal Article", "created": "2020-09-02", "title": "Assessing the Potential for Mobilization of Old Soil Carbon After Permafrost Thaw: A Synthesis of 14C Measurements From the Northern Permafrost Region", "description": "Abstract

The magnitude of future emissions of greenhouse gases from the northern permafrost region depends crucially on the mineralization of soil organic carbon (SOC) that has accumulated over millennia in these perennially frozen soils. Many recent studies have used radiocarbon (14C) to quantify the release of this \uffe2\uff80\uff9cold\uffe2\uff80\uff9d SOC as CO2 or CH4 to the atmosphere or as dissolved and particulate organic carbon (DOC and POC) to surface waters. We compiled ~1,900 14C measurements from 51 sites in the northern permafrost region to assess the vulnerability of thawing SOC in tundra, forest, peatland, lake, and river ecosystems. We found that growing season soil 14C\uffe2\uff80\uff90CO2 emissions generally had a modern (post\uffe2\uff80\uff901950s) signature, but that well\uffe2\uff80\uff90drained, oxic soils had increased CO2 emissions derived from older sources following recent thaw. The age of CO2 and CH4 emitted from lakes depended primarily on the age and quantity of SOC in sediments and on the mode of emission, and indicated substantial losses of previously frozen SOC from actively expanding thermokarst lakes. Increased fluvial export of aged DOC and POC occurred from sites where permafrost thaw caused soil thermal erosion. There was limited evidence supporting release of previously frozen SOC as CO2, CH4, and DOC from thawing peatlands with anoxic soils. This synthesis thus suggests widespread but not universal release of permafrost SOC following thaw. We show that different definitions of \uffe2\uff80\uff9cold\uffe2\uff80\uff9d sources among studies hamper the comparison of vulnerability of permafrost SOC across ecosystems and disturbances. We also highlight opportunities for future 14C studies in the permafrost region.This paper evaluates the complexities of radiocarbon (14C) dates from soil organic matter (SOM) in archaeological scenarios. The aqueous NaOH-insoluble residual SOM from Neolithic to medieval sites in NW Spain produced consistently older calibrated14C ages than NaOH-extractable SOM. Using pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and thermally assisted hydrolysis and methylation (THM-GC-MS), we analyzed the molecular composition of these SOM fractions, aiming to understand the differences in14C ages and to gain insight on SOM dynamics in relation to age fractionation. The molecular composition of the NaOH-extractable SOM, which accounts for roughly two-thirds of total SOM, has a larger proportion of microbial detritus than the NaOH-insoluble SOM. This might suggest that the discrepancies between the two fractions is due to microbial rejuvenation in the extractable fraction, leading to14C results that are younger than the activity that is to be dated. However, archaeological evidence presented here unambiguously shows that the14C age of the extractable SOM provides the more accurate age for the targeted activity, and that the insoluble fraction contains inherited old carbon. After statistical data evaluation using Partial Least Squares-Regression (PLS-R), it is concluded that this inherited SOM is a mixture of Black Carbon from wild and/or domestic fires and recalcitrant aliphatic SOM.One of the largest uncertainties in the terrestrial carbon cycle is the timing and magnitude of soil organic carbon (SOC) response to climate and vegetation change. This uncertainty prevents models from adequately capturing SOC dynamics and challenges the assessment of management and climate change effects on soils. Reducing these uncertainties requires simultaneous investigation of factors controlling the amount (SOC abundance) and duration (SOC persistence) of stored C. We present a global synthesis of SOC and radiocarbon profiles (nProfile\uffe2\uff80\uff89=\uffe2\uff80\uff89597) to assess the timescales of SOC storage. We use a combination of statistical and depth\uffe2\uff80\uff90resolved compartment models to explore key factors controlling the relationships between SOC abundance and persistence across pedo\uffe2\uff80\uff90climatic regions and with soil depth. This allows us to better understand (i) how SOC abundance and persistence covary across pedo\uffe2\uff80\uff90climatic regions and (ii) how the depth dependence of SOC dynamics relates to climatic and mineralogical controls on SOC abundance and persistence. We show that SOC abundance and persistence are differently related; the controls on these relationships differ substantially between major pedo\uffe2\uff80\uff90climatic regions and soil depth. For example, large amounts of persistent SOC can reflect climatic constraints on soils (e.g., in tundra/polar regions) or mineral absorption, reflected in slower decomposition and vertical transport rates. In contrast, lower SOC abundance can be found with lower SOC persistence (e.g., in highly weathered tropical soils) or higher SOC persistence (e.g., in drier and less productive regions). We relate variable patterns of SOC abundance and persistence to differences in the processes constraining plant C input, microbial decomposition, vertical C transport and mineral SOC stabilization potential. This process\uffe2\uff80\uff90oriented grouping of SOC abundance and persistence provides a valuable benchmark for global C models, highlighting that pedo\uffe2\uff80\uff90climatic boundary conditions are crucial for predicting the effects of climate change and soil management on future C abundance and persistence.Despite the global significance of the subsurface biosphere, the degree to which it depends on surface organic carbon (OC) is still poorly understood. Here, we compare stable and radiogenic carbon isotope compositions of microbial phospholipid fatty acids (PLFAs) with those of in situ potential microbial C sources to assess the major C sources for subsurface microorganisms in biogeochemical distinct shallow aquifers (Critical Zone Exploratory, Thuringia Germany). Despite the presence of younger OC, the microbes assimilated 14C\uffe2\uff80\uff90free OC to varying degrees; ~31% in groundwater within the oxic zone, ~47% in an iron reduction zone, and ~70% in a sulfate reduction/anammox zone. The persistence of trace amounts of mature and partially biodegraded hydrocarbons suggested that autochthonous petroleum\uffe2\uff80\uff90derived hydrocarbons were a potential 14C\uffe2\uff80\uff90free C source for heterotrophs in the oxic zone. In this zone, \uffce\uff9414C values of dissolved inorganic carbon (\uffe2\uff88\uff92366\uffc2\uffa0\uffc2\uffb1\uffc2\uffa018\uffe2\uff80\uffb0) and 11MeC16:0 (\uffe2\uff88\uff92283\uffc2\uffa0\uffc2\uffb1\uffc2\uffa032\uffe2\uff80\uffb0), an important component in autotrophic nitrite oxidizers, were similar enough to indicate that autotrophy is an important additional C fixation pathway. In anoxic zones, methane as an important C source was unlikely since the 13C\uffe2\uff80\uff90fractionations between the PLFAs and CH4 were inconsistent with kinetic isotope effects associated with methanotrophy. In the sulfate reduction/anammox zone, the strong 14C\uffe2\uff80\uff90depletion of 10MeC16:0 (\uffe2\uff88\uff92942\uffc2\uffa0\uffc2\uffb1\uffc2\uffa022\uffe2\uff80\uffb0), a PLFA common in sulfate reducers, indicated that those bacteria were likely to play a critical part in 14C\uffe2\uff80\uff90free sedimentary OC cycling. Results indicated that the 14C\uffe2\uff80\uff90content of microbial biomass in shallow sedimentary aquifers results from complex interactions between abundance and bioavailability of naturally occurring OC, hydrogeology, and specific microbial metabolisms.We evaluated global soil organic carbon (SOC) stocks and turnover time predictions from a global land model (ELMv1\uffe2\uff80\uff90ECA) integrated in an Earth System Model (E3SM) by comparing them with observed soil bulk and \uffce\uff9414C values around the world. We analyzed observed and simulated SOC stocks and \uffce\uff9414C values using machine learning methods at the Earth System Model grid cell scale (~200\uffc2\uffa0km). In grid cells with sufficient observations, the model provided reasonable estimates of soil carbon stocks across soil depth and \uffce\uff9414C values near the surface but underestimated \uffce\uff9414C at depth. Among many explanatory variables, soil albedo index, soil order, plant function type, air temperature, and SOC content were major factors affecting predicted SOC \uffce\uff9414C values. The influences of soil albedo index, soil order, and air temperature were primarily important in the shallow subsurface (\uffe2\uff89\uffa430\uffc2\uffa0cm). We also performed sensitivity studies using different vertical root distributions and decomposition turnover times and compared to observed SOC stock and \uffce\uff9414C profiles. The analyses support the role of vegetation in affecting soil carbon turnover, particularly in deep soil, possibly through supplying fresh carbon and degrading physical\uffe2\uff80\uff90chemical protection of SOC via root activities. Allowing for grid cell\uffe2\uff80\uff90specific rooting and decomposition rates substantially reduced discrepancies between observed and predicted \uffce\uff9414C values and SOC content. Our results highlight the need for more explicit representation of roots, microbes, and soil physical protection in land models.Radiocarbon (14C) is a powerful tracer of the global carbon cycle that is commonly used to assess carbon cycling rates in various Earth system reservoirs and as a benchmark to assess model performance. Therefore, it has been recommended that Earth System Models (ESMs) participating in the Coupled Model Intercomparison Project Phase 6 report predicted radiocarbon values for relevant carbon pools. However, a detailed representation of radiocarbon dynamics may be an impractical burden on model developers. Here, we present an alternative approach to compute radiocarbon values from the numerical output of an ESM that does not explicitly represent these dynamics. The approach requires computed 12C stocks and fluxes among all carbon pools for a particular simulation of the model. From this output, a time\uffe2\uff80\uff90dependent linear compartmental system is computed with its respective state\uffe2\uff80\uff90transition matrix. Using transient atmospheric 14C values as inputs, the state\uffe2\uff80\uff90transition matrix is then applied to compute radiocarbon values for each pool, the average value for the entire system, and component fluxes. We demonstrate the approach with ELMv1\uffe2\uff80\uff90ECA, the land component of an ESM model that explicitly represents 12C, and 14C in 7 soil pools and 10 vertical layers. Results from our proposed method are highly accurate (relative error <0.01%) compared with the ELMv1\uffe2\uff80\uff90ECA 12C and 14C predictions, demonstrating the potential to use this approach in CMIP6 and other model simulations that do not explicitly represent 14C.The radiocarbon signature of respired CO2 (\uffe2\uff88\uff8614C\uffe2\uff80\uff90CO2) measured in laboratory soil incubations integrates contributions from soil carbon pools with a wide range of ages, making it a powerful model constraint. Incubating archived soils enriched by \uffe2\uff80\uff9cbomb\uffe2\uff80\uff90C\uffe2\uff80\uff9d from mid\uffe2\uff80\uff9020th century nuclear weapons testing would be even more powerful as it would enable us to trace this pulse over time. However, air\uffe2\uff80\uff90drying and subsequent rewetting of archived soils, as well as storage duration, may alter the relative contribution to respiration from soil carbon pools with different cycling rates. We designed three experiments to assess air\uffe2\uff80\uff90drying and rewetting effects on \uffe2\uff88\uff8614C\uffe2\uff80\uff90CO2 with constant storage duration (Experiment 1), without storage (Experiment 2), and with variable storage duration (Experiment 3). We found that air\uffe2\uff80\uff90drying and rewetting led to small but significant (\uffce\uffb1\uffc2\uffa0<\uffc2\uffa00.05) shifts in \uffe2\uff88\uff8614C\uffe2\uff80\uff90CO2 relative to undried controls in all experiments, with grassland soils responding more strongly than forest soils. Storage duration (4\uffe2\uff80\uff9314\uffc2\uffa0y) did not have a substantial effect. Mean differences (95% CIs) for experiments 1, 2, and 3 were: 23.3\uffe2\uff80\uffb0 (\uffc2\uffb16.6), 19.6\uffe2\uff80\uffb0 (\uffc2\uffb110.3), and 29.3\uffe2\uff80\uffb0 (\uffc2\uffb129.1) for grassland soils, versus \uffe2\uff88\uff9211.6\uffe2\uff80\uffb0 (\uffc2\uffb14.1), 12.7\uffe2\uff80\uffb0 (\uffc2\uffb18.5), and \uffe2\uff88\uff9224.2\uffe2\uff80\uffb0 (\uffc2\uffb113.2) for forest soils. Our results indicate that air\uffe2\uff80\uff90drying and rewetting soils mobilizes a slightly older pool of carbon that would otherwise be inaccessible to microbes, an effect that persists throughout the incubation. However, as the bias in \uffe2\uff88\uff8614C\uffe2\uff80\uff90CO2 from air\uffe2\uff80\uff90drying and rewetting is small, measuring \uffe2\uff88\uff8614C\uffe2\uff80\uff90CO2 in incubations of archived soils appears to be a promising technique for constraining soil carbon models.On\uffe2\uff80\uff90going shrinkage of Greenland's icecap, permafrost thaw, and changes in precipitation are exposing its landscapes to erosion and remobilization of ancient organic carbon (OC) held in soils and sedimentary rocks. The fate of this OC and potential feedbacks to climate are still unclear. Here, we show that the glacial Zackenberg river (Northeastern Greenland) exports aged particulate OC (POC, uncalibrated radiocarbon ages of \uffe2\uff88\uffbc4,000\uffc2\uffa0years). Many of the smaller periglacial streams affected by abrupt permafrost thaw transport substantially older POC (up to 32,000\uffc2\uffa0years), especially with enhanced discharge following intense precipitation. Mineralogical analysis, and density and size fractionation of soils and both glacial and nonglacial river sediments reveal that OC is largely associated with phyllosilicate minerals, suggesting stabilization against microbial processing. Enhanced export of ancient, mineral\uffe2\uff80\uff90associated OC as a consequence of summer rainfall may accelerate translocation of OC from terrestrial to marine environments, but could have limited consequences for climate. Climate warming is expected to mobilize northern permafrost and peat organic carbon (PP-C), yet magnitudes and system specifics of even current releases are poorly constrained. While part of the PP-C will degrade at point of thaw to CO 2 and CH 4 to directly amplify global warming, another part will enter the fluvial network, potentially providing a window to observe large-scale PP-C remobilization patterns. Here, we employ a decade-long, high-temporal resolution record of 14 C in dissolved and particulate organic carbon (DOC and POC, respectively) to deconvolute PP-C release in the large drainage basins of rivers across Siberia: Ob, Yenisey, Lena, and Kolyma. The 14 C-constrained estimate of export specifically from PP-C corresponds to only 17 \uffc2\uffb1 8% of total fluvial organic carbon and serves as a benchmark for monitoring changes to fluvial PP-C remobilization in a warming Arctic. Whereas DOC was dominated by recent organic carbon and poorly traced PP-C (12 \uffc2\uffb1 8%), POC carried a much stronger signature of PP-C (63 \uffc2\uffb1 10%) and represents the best window to detect spatial and temporal dynamics of PP-C release. Distinct seasonal patterns suggest that while DOC primarily stems from gradual leaching of surface soils, POC reflects abrupt collapse of deeper deposits. Higher dissolved PP-C export by Ob and Yenisey aligns with discontinuous permafrost that facilitates leaching, whereas higher particulate PP-C export by Lena and Kolyma likely echoes the thermokarst-induced collapse of Pleistocene deposits. Quantitative 14 C-based fingerprinting of fluvial organic carbon thus provides an opportunity to elucidate large-scale dynamics of PP-C remobilization in response to Arctic warming. Extensive release of methane from sediments of the world\uffe2\uff80\uff99s largest continental shelf, the East Siberian Arctic Ocean (ESAO), is one of the few Earth system processes that can cause a net transfer of carbon from land/ocean to the atmosphere and thus amplify global warming on the timescale of this century. An important gap in our current knowledge concerns the contributions of different subsea pools to the observed methane releases. This knowledge is a prerequisite to robust predictions on how these releases will develop in the future. Triple-isotope\uffe2\uff80\uff93based fingerprinting of the origin of the highly elevated ESAO methane levels points to a limited contribution from shallow microbial sources and instead a dominating contribution from a deep thermogenic pool.Permafrost thaw will release additional carbon dioxide into the atmosphere resulting in a positive feedback to climate change. However, the mineralization dynamics of organic matter (OM) stored in permafrost-affected soils remain unclear. We used physical soil fractionation, radiocarbon measurements, incubation experiments, and a dynamic decomposition model to identify distinct vertical pattern in OM decomposability. The observed differences reflect the type of OM input to the subsoil, either by cryoturbation or otherwise, e.g. by advective water-borne transport of dissolved OM. In non-cryoturbated subsoil horizons, most OM is stabilized at mineral surfaces or by occlusion in aggregates. In contrast, pockets of OM-rich cryoturbated soil contain sufficient free particulate OM for microbial decomposition. After thaw, OM turnover is as fast as in the upper active layer. Since cryoturbated soils store ca. 450 Pg carbon, identifying differences in decomposability according to such translocation processes has large implications for the future global carbon cycle and climate, and directs further process model development.Carbon (C) assimilation can be severely impaired during periods of environmental stress, like drought or defoliation, making trees heavily dependent on the use of C reserve pools for survival; yet, the dynamics of reserve use during periods of reduced C supply are still poorly understood. We used stem girdling in mature poplar trees (Populus tremula L. hybrids), a lipid-storing species, to permanently interrupt the phloem C transport and induced C shortage in the isolated stem section below the girdle and monitored metabolic activity during three campaigns in the growing seasons of 2018, 2019 and 2021. We measured respiratory fluxes (CO2 and O2), non-structural carbon concentration, the respiratory substrate (based on isotopic analysis and CO2/O2 ratio) and the age of the respiratory substrate (based on radiocarbon analysis). Our study shows that poplar trees can survive long periods of reduced C supply from the canopy by switching in metabolism from recent carbohydrates to older storage pools with a potential mixture of respiratory substrates, including lipids. This mechanism of stress resilience can explain why tree decline may take many years before death occurs. Organic carbon (OC) association with soil minerals stabilizes OC on timescales reflecting the strength of mineral\uffe2\uff80\uff93C interactions. We applied ramped thermal oxidation to subsoil B horizons with different mineral\uffe2\uff80\uff93C associations to separate OC according to increasing temperature of oxidation, i.e. thermal activation energy. Generally, OC released at lower temperatures was richer in bioavailable forms like polysaccharides, while OC released at higher temperatures was more aromatic. Organic carbon associated with pedogenic oxides was released at lower temperatures and had a narrow range of 14 C content. By contrast, N-rich compounds were released at higher temperatures from samples with 2\uffe2\uff80\uff89:\uffe2\uff80\uff891 clays and short-range ordered (SRO) amorphous minerals. Temperatures of release overlapped for SRO minerals and crystalline oxides, although the mean age of OC released was older for the SRO. In soils with more mixed mineralogy, the added presence of older OC released at temperatures greater than 450\uffc2\uffb0C from clays resulted in a broader distribution of OC ages within the sample, especially for soils rich in 2\uffe2\uff80\uff89:\uffe2\uff80\uff891 layer expandable clays such as smectite. While pedogenic setting affects mineral stability and absolute OC age, mineralogy controls the structure of OC age distribution within a sample, which may provide insight into model structures and OC dynamics under changing conditions.

This article is part of the Theo Murphy meeting issue \uffe2\uff80\uff98Radiocarbon in the Anthropocene\uffe2\uff80\uff99.Soil moisture affects microbial decay of SOM and rhizosphere respiration (RR) in temperate forest soils, but isolating the response of soil respiration (SR) to summer drought and subsequent wetting is difficult because moisture changes are often confounded with temperature variation. We distinguished between temperature and moisture effects by simulation of prolonged soil droughts in a mixed deciduous forest at the Harvard Forest, Massachusetts. Roofs constructed over triplicate 5 \uffc3\uff97 5\uffe2\uff80\uff83m2plots excluded throughfall water during the summers of 2001 (168\uffe2\uff80\uff83mm) and 2002 (344\uffe2\uff80\uff83mm), while adjacent control plots received ambient throughfall and the same natural temperature regime. In 2003, throughfall was not excluded to assess the response of SR under natural weather conditions after two prolonged summer droughts. Throughfall exclusion significantly decreased mean SR rate by 53\uffe2\uff80\uff83mg\uffe2\uff80\uff83C\uffe2\uff80\uff83m\uffe2\uff88\uff922\uffe2\uff80\uff83h\uffe2\uff88\uff921over 84 days in 2001, and by 68\uffe2\uff80\uff83mg\uffe2\uff80\uff83C\uffe2\uff80\uff83m\uffe2\uff88\uff922\uffe2\uff80\uff83h\uffe2\uff88\uff921over 126 days in 2002, representing 10\uffe2\uff80\uff9330% of annual SR in this forest and 35\uffe2\uff80\uff9375% of annual net ecosystem exchange (NEE) of C. The differences in SR were best explained by differences in gravimetric water content in the Oi horizon (r2=0.69) and the Oe/Oa horizon (r2=0.60). Volumetric water content of the A horizon was not significantly affected by throughfall exclusion. The radiocarbon signature of soil CO2efflux and of CO2respired during incubations of O horizon, A horizon and living roots allowed partitioning of SR into contributions from young C substrate (including RR) and from decomposition of older SOM. RR (root respiration and microbial respiration of young substrates in the rhizosphere) made up 43\uffe2\uff80\uff9371% of the total C respired in the control plots and 41\uffe2\uff80\uff9380% in the exclusion plots, and tended to increase with drought. An exception to this trend was an interesting increase in CO2efflux of radiocarbon\uffe2\uff80\uff90rich substrates during a period of abundant growth of mushrooms.

Our results suggest that prolonged summer droughts decrease primarily heterotrophic respiration in the O horizon, which could cause increases in the storage of soil organic carbon in this forest. However, the C stored during two summers of simulated drought was only partly released as increased respiration during the following summer of natural throughfall. We do not know if this soil C sink during drought is transient or long lasting. In any case, differential decomposition of the O horizon caused by interannual variation of precipitation probably contributes significantly to observed interannual variation of NEE in temperate forests.

", "keywords": ["Ecology", "04 agricultural and veterinary sciences", "Biological Sciences", "15. Life on land", "soil respiration", "6. Clean water", "soil drought", "heterotrophic respiration", "rhizosphere respiration", "13. Climate action", "soil organic matter", "temperate forest", "radiocarbon", "0401 agriculture", " forestry", " and fisheries", "soil wetting", "soil moisture", "Q(10)", "Environmental Sciences"]}, "links": [{"href": "https://escholarship.org/content/qt3mk9v58k/qt3mk9v58k.pdf"}, {"href": "https://doi.org/10.1111/j.1365-2486.2005.001058.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.1365-2486.2005.001058.x", "name": "item", "description": "10.1111/j.1365-2486.2005.001058.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/j.1365-2486.2005.001058.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2005-11-28T00:00:00Z"}}, {"id": "10.1111/gcb.17320", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:19:58Z", "type": "Journal Article", "created": "2024-05-16", "title": "Controls and relationships of soil organic carbon abundance and persistence vary across pedo\u2010climatic regions", "description": "Abstract

One of the largest uncertainties in the terrestrial carbon cycle is the timing and magnitude of soil organic carbon (SOC) response to climate and vegetation change. This uncertainty prevents models from adequately capturing SOC dynamics and challenges the assessment of management and climate change effects on soils. Reducing these uncertainties requires simultaneous investigation of factors controlling the amount (SOC abundance) and duration (SOC persistence) of stored C. We present a global synthesis of SOC and radiocarbon profiles (nProfile\uffe2\uff80\uff89=\uffe2\uff80\uff89597) to assess the timescales of SOC storage. We use a combination of statistical and depth\uffe2\uff80\uff90resolved compartment models to explore key factors controlling the relationships between SOC abundance and persistence across pedo\uffe2\uff80\uff90climatic regions and with soil depth. This allows us to better understand (i) how SOC abundance and persistence covary across pedo\uffe2\uff80\uff90climatic regions and (ii) how the depth dependence of SOC dynamics relates to climatic and mineralogical controls on SOC abundance and persistence. We show that SOC abundance and persistence are differently related; the controls on these relationships differ substantially between major pedo\uffe2\uff80\uff90climatic regions and soil depth. For example, large amounts of persistent SOC can reflect climatic constraints on soils (e.g., in tundra/polar regions) or mineral absorption, reflected in slower decomposition and vertical transport rates. In contrast, lower SOC abundance can be found with lower SOC persistence (e.g., in highly weathered tropical soils) or higher SOC persistence (e.g., in drier and less productive regions). We relate variable patterns of SOC abundance and persistence to differences in the processes constraining plant C input, microbial decomposition, vertical C transport and mineral SOC stabilization potential. This process\uffe2\uff80\uff90oriented grouping of SOC abundance and persistence provides a valuable benchmark for global C models, highlighting that pedo\uffe2\uff80\uff90climatic boundary conditions are crucial for predicting the effects of climate change and soil management on future C abundance and persistence.Soils store large quantities of carbon in the subsoil (below 0.2\uffe2\uff80\uff89m depth) that is generally old and believed to be stabilized over centuries to millennia, which suggests that subsoil carbon sequestration (CS) can be used as a strategy for climate change mitigation. In this article, we review the main biophysical processes that contribute to carbon storage in subsoil and the main mathematical models used to represent these processes. Our guiding objective is to review whether a process understanding of soil carbon movement in the vertical profile can help us to assess carbon storage and persistence at timescales relevant for climate change mitigation. Bioturbation, liquid phase transport, belowground carbon inputs, mineral association, and microbial activity are the main processes contributing to the formation of soil carbon profiles, and these processes are represented in models using the diffusion\uffe2\uff80\uff93advection\uffe2\uff80\uff93reaction paradigm. Based on simulation examples and measurements from carbon and radiocarbon profiles across biomes, we found that advective and diffusive transport may only play a secondary role in the formation of soil carbon profiles. The difference between vertical root inputs and decomposition seems to play a primary role in determining the shape of carbon change with depth. Using the transit time of carbon to assess the timescales of carbon storage of new inputs, we show that only small quantities of new carbon inputs travel through the profile and can be stabilized for time horizons longer than 50\uffe2\uff80\uff89years, implying that activities that promote CS in the subsoil must take into consideration the very small quantities that can be stabilized in the long term.Given the importance of soil for the global carbon cycle, it is essential to understand not only how much carbon soil stores but also how long this carbon persists. Previous studies have shown that the amount and age of soil carbon are strongly affected by the interaction of climate, vegetation, and mineralogy. However, these findings are primarily based on studies from temperate regions and from fine\uffe2\uff80\uff90scale studies, leaving large knowledge gaps for soils from understudied regions such as sub\uffe2\uff80\uff90Saharan Africa. In addition, there is a lack of data to validate modeled soil C dynamics at broad scales. Here, we present insights into organic carbon cycling, based on a new broad\uffe2\uff80\uff90scale radiocarbon and mineral dataset for sub\uffe2\uff80\uff90Saharan Africa. We found that in moderately weathered soils in seasonal climate zones with poorly crystalline and reactive clay minerals, organic carbon persists longer on average (topsoil: 201\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff89130\uffe2\uff80\uff89years; subsoil: 645\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff89385\uffe2\uff80\uff89years) than in highly weathered soils in humid regions (topsoil: 140\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff8946\uffe2\uff80\uff89years; subsoil: 454\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff89247\uffe2\uff80\uff89years) with less reactive minerals. Soils in arid climate zones (topsoil: 396\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff89339\uffe2\uff80\uff89years; subsoil: 963\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff89669\uffe2\uff80\uff89years) store organic carbon for periods more similar to those in seasonal climate zones, likely reflecting climatic constraints on weathering, carbon inputs and microbial decomposition. These insights into the timescales of organic carbon persistence in soils of sub\uffe2\uff80\uff90Saharan Africa suggest that a process\uffe2\uff80\uff90oriented grouping of soils based on pedo\uffe2\uff80\uff90climatic conditions may be useful to improve predictions of soil responses to climate change at broader scales.

Late frost can destroy the photosynthetic apparatus of trees. We hypothesized that this can alter the normal cyclic dynamics of C\uffe2\uff80\uff90reserves in the wood.

We measured soluble sugar concentrations and radiocarbon signatures (\uffce\uff9414C) of soluble nonstructural carbon (NSC) in woody tissues sampled from a Mediterranean beech forest that was completely defoliated by an exceptional late frost in 2016. We used the bomb radiocarbon approach to estimate the time elapsed since fixation of mobilized soluble sugars.

During the leafless period after the frost event, soluble sugar concentrations declined sharply while \uffce\uff9414C of NSC increased. This can be explained by the lack of fresh assimilate supply and a mobilization of C from reserve pools. Soluble NSC became increasingly older during the leafless period, with a maximum average age of 5\uffc2\uffa0yr from samples collected 27\uffc2\uffa0d before canopy recovery. Following leaf re\uffe2\uff80\uff90growth, soluble sugar concentrations increased and \uffce\uff9414C of soluble NSC decreased, indicating the allocation of new assimilates to the stem soluble sugars pool.

These data highlight that beech trees rapidly mobilize reserve C to survive strong source\uffe2\uff80\uff93sink imbalances, for example due to late frost, and show that NSC is a key trait for tree resilience under global change.

Soil carbon has been measured for over a century in applications ranging from understanding biogeochemical processes in natural ecosystems to quantifying the productivity and health of managed systems. Consolidating diverse soil carbon datasets is increasingly important to maximize their value, particularly with growing anthropogenic and climate change pressures. In this progress report, we describe recent advances in soil carbon data led by the International Soil Carbon Network and other networks. We highlight priority areas of research requiring soil carbon data, including (a) quantifying boreal, arctic and wetland carbon stocks, (b) understanding the timescales of soil carbon persistence using radiocarbon and chronosequence studies, (c) synthesizing long-term and experimental data to inform carbon stock vulnerability to global change, (d) quantifying root influences on soil carbon and (e) identifying gaps in model\u2013data integration. We also describe the landscape of soil datasets currently available, highlighting their strengths, weaknesses and synergies. Now more than ever, integrated soil data are needed to inform climate mitigation, land management and agricultural practices. This report will aid new data users in navigating various soil databases and encourage scientists to make their measurements publicly available and to join forces to find soil-related solutions.

", "keywords": ["long-term ecological research", "2. Zero hunger", "soil chronosequence", "model\u2013data integration", "soil carbon stabilization", "Soil carbon data", "15. Life on land", "01 natural sciences", "wetland carbon", "6. Clean water", "root traits", "soil database", "soil radiocarbon", "13. Climate action", "11. Sustainability", "0105 earth and related environmental sciences"]}, "links": [{"href": "http://journals.sagepub.com/doi/pdf/10.1177/0309133319873309"}, {"href": "https://doi.org/10.1177/0309133319873309"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Progress%20in%20Physical%20Geography%3A%20Earth%20and%20Environment", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1177/0309133319873309", "name": "item", "description": "10.1177/0309133319873309", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1177/0309133319873309"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-09-08T00:00:00Z"}}, {"id": "10.1590/s0100-204x2012000500005", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:21:10Z", "type": "Journal Article", "created": "2012-06-23", "title": "Biochar Effect On The Mineralization Of Soil Organic Matter", "description": "

The objective of this work was to verify whether the addition of biochar to the soil affects the degradation of litter and of soil organic matter (SOM). In order to investigate the effect of biochar on the mineralization of barley straw, soil was incubated with 14C-labelled barley straw with or without unlabelled biochar. To investigate the effect of straw on the mineralization of biochar, soil was incubated with 14C-labelled biochar with or without straw. In addition, to investigate the effect of biochar on old SOM, a soil labelled by applying labelled straw 40 years ago was incubated with different levels of biochar. All experiments had a control treatment, without any soil amendment. The effect of biochar on the straw mineralization was small and nonsignificant. Without biochar, 48\uffc2\uffb10.2% of the straw carbon was mineralized within the 451 days of the experiment. In comparison, 45\uffc2\uffb11.6% of C was mineralized after biochar addition of 1.5 g kg-1. In the SOM-labelled soil, the organic matter mineralized more slowly with the increasing doses of biochar. Biochar addition at 7.7 g kg-1 reduced SOM mineralization from 6.6 to 6.3%, during the experimental period. The addition of 15.5 g kg-1 of biochar reduced the mineralized SOM to 5.7%. There is no evidence of increased degradation of either litter or SOM due to biochar addition; consequently, there is no evidence of decreased stability of SOM.

", "keywords": ["priming effect", "estabilidade da mat\u00e9ria org\u00e2nica", "2. Zero hunger", "anthropogenic dark earth", "terra preta de \u00edndio", "organic matter stability", "Agriculture (General)", "04 agricultural and veterinary sciences", "15. Life on land", "radiocarbono", "6. Clean water", "S1-972", "efeito 'priming'", "radiocarbon", "0401 agriculture", " forestry", " and fisheries"], "contacts": [{"organization": "Bruun, Sander, EL-Zehery, Tarek,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1590/s0100-204x2012000500005"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Pesquisa%20Agropecu%C3%A1ria%20Brasileira", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1590/s0100-204x2012000500005", "name": "item", "description": "10.1590/s0100-204x2012000500005", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1590/s0100-204x2012000500005"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2012-05-01T00:00:00Z"}}, {"id": "10.3389/feart.2021.681931", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:22:15Z", "type": "Journal Article", "created": "2021-07-01", "title": "The Reservoir Age Effect Varies With the Mobilization of Pre-Aged Organic Carbon in a High-Altitude Central Asian Catchment", "description": "

Lake sediments provide excellent archives to study past environmental and hydrological changes at high temporal resolution. However, their utility is often restricted by chronological uncertainties due to the \uffe2\uff80\uff9creservoir age effect\uffe2\uff80\uff9d (RAE), a phenomenon that results in anomalously old radiocarbon ages of total organic carbon (TOC) samples that is mainly attributed to the contribution of pre-aged carbon from aquatic organisms. Although the RAE is a well-known problem especially in high altitude lakes, detailed studies analyzing the temporal variations in the contribution of terrestrial and aquatic organic carbon (OC) on the RAE are scarce. This is partially due to the complexity of isolating individual compounds for subsequent compound-specific radiocarbon analysis (CSRA). We developed a rapid method for isolating individual short-chain (C16and C18) and long-chain (&gt;C24) saturated fatty acid methyl esters (FAMEs) by using high-pressure liquid chromatography (HPLC). Our method introduces only minor contaminations (0.50 \uffc2\uffb1 0.22\uffc2\uffa0\uffc2\uffb5g dead carbon on average) and requires only few injections (\uffe2\uff89\uffa410), therefore offering clear advantages over traditional preparative gas chromatography (prep-GC). Here we show that radiocarbon values (\uffce\uff9414C) of long-chain FAs, which originate from terrestrial higher plant waxes, reflect carbon from a substantially pre-aged OC reservoir, whereas the \uffce\uff9414C of short-chain FAs that originate from aquatic sources were generally less pre-aged.14C ages obtained from the long-chain FAs are in closer agreement with14C ages of the corresponding bulk TOC fraction, indicating a high control of pre-aged terrestrial OC input from the catchment on TOC-derived14C ages. Variations in the age offset between terrestrial and aquatic biomarkers are related to changes in bulk sediment log(Ti/K) that reflect variations in detrital input from the catchment. Our results indicate that the chronological offset between terrestrial and aquatic OC in this high-altitude catchment is mainly driven by temporal variations in the mobilization of pre-aged OC from the catchment. In conclusion, to obtain accurate and process-specific lake sediment chronologies, attention must be given to the temporal dynamics of the RAE. Variations in the apparent ages of aquatic and terrestrial contributions to the sediment and their mass balance can substantially alter the reservoir age effect.The problems regarding hunter-gatherer/early farmer interactions are quite an important topic in southeast European archaeology. According to the available data, the two economic subsistence systems have coexisted for some 2000 years during the 6th\uffe2\uff80\uff934th millennia cal BC (Telegin 1985; Lillie et al., 2001). In some areas, hunter-gatherer and early farmer sites are located just a few kilometers apart. The Southern Buh River valley has yielded evidence of Linear Pottery culture, early Trypillia and Trypillia B1 Neolithic settlements as well as hunter-gatherer sites with pottery attributable to the so-called sub-Neolithic or para-Neolithic (Haskevych et al., 2019; Kiosak et al., 2021). Trial-trenches have been opened within some of these sites, which have been radiocarbon-dated from Bern University laboratory (LARA). Soil samples for micromorphological analysis have been collected from these sites to interpret their paleogenetic formation. The soil development is attested since, at least, the beginning of the 5th mill BC, followed by the developed of chernozem soils, which was interrupted by an erosional episode in the end of 5th millennium BC. The available data show that the soils of early farmers arable as are the present day ones. The early farmers were able to exploit relatively heavy soils to cultivate wheat and barley as early as 5250\uffe2\uff80\uff935050 cal BC. In contrast, the sites of ceramic hunter-gatherers were often located on the soils which formed under wet conditions along seasonally flooded riverbanks, which were almost unsuitable for agricultural practices.

", "keywords": ["2. Zero hunger", "S", "radiocarbon dates", "Neolithization of eastern Europe", "Agriculture", "0601 history and archaeology", "06 humanities and the arts", "15. Life on land", "Ukraine", "paleopedogenesis", "Neolithization of eastern Europe; Ukraine; radiocarbon dates; soil micromorphology; paleopedogenesis", "soil micromorphology"]}, "links": [{"href": "http://www.mdpi.com/2073-445X/12/2/388/pdf"}, {"href": "https://iris.unive.it/bitstream/10278/5017342/1/land-12-00388%20%283%29.pdf"}, {"href": "https://www.mdpi.com/2073-445X/12/2/388/pdf"}, {"href": "https://doi.org/10.3390/land12020388"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Land", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/land12020388", "name": "item", "description": "10.3390/land12020388", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/land12020388"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2023-01-31T00:00:00Z"}}, {"id": "10.37098/va-2020-12-31-39", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:22:53Z", "type": "Journal Article", "created": "2021-05-01", "title": "Rapid climatic event 8,200 calBP and social dynamics in North-Western Pontic region", "description": "The article treats the archaeological record of North-Western Pontic region in search of traces of 8200 calBP event. The two different approaches are applied: summation of 14C dates and a site-oriented approach. In the framework of the latter we refer to materials of Melnychna Krucha site, which contains a sequence covering 7500-1200\u00a0y.\u00a0BCE. Twelve AMS dates highlight the probable gap in the sequence of human habitation on the site around 6250-6000\u00a0y.\u00a0BCE, around the expected timing of the paleoclimatic oscillation. It seems that the event was accompanied by drastic changes in the watering of major rivers of Northern Pontic area like Southern Buh or Dnieper.", "keywords": ["soil sequence", "radiocarbon dating", "subsistence patterns", "abrupt climate change"]}, "links": [{"href": "https://doi.org/10.37098/va-2020-12-31-39"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/VITA%20ANTIQUA", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.37098/va-2020-12-31-39", "name": "item", "description": "10.37098/va-2020-12-31-39", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.37098/va-2020-12-31-39"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-01-01T00:00:00Z"}}, {"id": "10.5061/dryad.0k6djhb5k", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:23:06Z", "type": "Dataset", "created": "2023-08-29", "title": "Empirical data and model simulations of the effect of repeated hurricanes on soil carbon dynamics in a humid tropical forest", "description": "unspecifiedSite description Soils were sampled from the Bisley Experimental Watershed of the LEF, Puerto Rico (18.3157 deg. N, 65.7487 deg W), a Long-Term Ecological Research and Critical Zone Observatory and Network site (https://luq.lter.network). The mean maximum daily temperature at Bisley was 27 \u00baC between 1993 and 2010 (Gonzales, 2020), with little seasonality. The mean annual precipitation at Bisley was 3883 (\u00b1 864 s.d.) mm y-1 from 1988 through 2014 (Gonz\u00e1lez, 2017; Murphy et al., 2017). Rainfall occurs all year, though January through April experience slightly less precipitation than other months (Heartsill-Scalley et al., 2007). The site is a humid tropical forest with a diverse tree community of approximately 170 species > 4 cm diameter at breast height (Weaver & Murphy, 1990), and dominated by tabonuco (Dacryodes excelsa Vahl). Elevation of Bisley spans from 261 m a.s.l. at the base to 450 m a.s.l. on the ridges (Scatena, 1989). Soils in Bisley are derived from volcaniclastic sediments of andesitic parent material (Scatena, 1989).\u00a0 Ridge soils are classified as Ultisols (Typic Haplohumults), while slope soils are classified as Oxisols (inceptic and Aquic Hapludox), and valley soils are classified as Inceptisols (Typic Epiaquaepts) (Hall et al., 2015; McDowell et al., 2012; Scatena, 1989). Detailed site descriptions can be found in Scatena (1989), Heartsill-Scalley et al (2010), and McDowell et al (2012). Here we refer to soil organic C (SOC) and soil C interchangeably because there is no detectable inorganic C in these soils. Hurricane occurrence\u00a0 Figure 1: Timeline of major hurricanes that have affected Luquillo Experimental Forest between sampling dates. Nine major hurricanes (category 3 or higher) have impacted Puerto Rico between 1851 and 2019 (L\u00f3pez-Marrero et al., 2019), and five of these hurricanes have impacted the LEF. Until 1998, hurricanes had historically directly impacted the LEF approximately every 60 years (Scatena & Larsen, 1991). Before the initial sampling campaign of this study, Hurricane San Cipri\u00e1n in 1932 was the most recent storm to cause major disturbance to the LEF (Scatena & Larsen, 1991).\u00a0 However, since sampling in 1988, four major hurricanes have impacted the forest (Figure 1). Hurricane Hugo (Category 3-4) in 1989, Hurricane Georges (Category 3) in 1998, and Hurricanes Irma and Maria (Categories 5 and 4, respectively) within two weeks in 2017. The trajectory and windspeeds of all these hurricanes caused widespread defoliation. Litterfall historically takes over five years to return to pre-hurricane levels (Scatena et al., 1996).\u00a0 Sampling Sample collection occurred in 1988 and again in 2018. In both years, samples were collected from three depths: 0\u201310 cm (the A horizon), 10\u201335 cm (all of the B1 horizon and part of B2), and 35\u201360 cm (B2 to C) using an 8 cm diameter soil auger. Soils in this study were sampled at three separate sites at least 40 m from one another for each of three topographic locations, ridge, slope, and upland valley. Two separate cores were taken from a fourth topographic location in the riparian valley, that characterized a smaller proportion of the area of these watersheds (Scatena & Lugo, 1995). Riparian valley sites were ephemeral streambeds with a high boulder presence that limited sampling to less than 25 cm depth in one case. Sampling sites from 1988 were marked with flags, and samples from 2018 were collected from within 15 m of the same locations as the replicates from 1988, for consistency. Samples collected in 1988 were analyzed for bulk density, pH, soil moisture, and a suite of soil chemical properties (see Silver et al. 1994). Samples were then air-dried and stored in closed Ziploc bags within paper bags in a storage facility in Richmond, CA, USA before density fractionation in 2018. Fresh samples collected in 2018 were also characterized for pH, soil moisture, and soil chemistry. Approximately 3 g subsamples from each fresh sample in 2018 were immediately extracted with 45 mL of 0.2 M sodium citrate/0.5 M ascorbate solution, shaken for 16 hours, then centrifuged and the supernatant decanted to measure concentrations of poorly crystalline iron (Fe) oxides. Within two days of being double-bagged in Ziploc bags, fresh samples were further subsampled and analyzed for pH in a 1:1 soil-to-water slurry (Thomas, 1996) and for gravimetric soil moisture by oven-drying ~10 g subsamples at 105 \u00baC until a constant weight. Soil samples were air-dried before further processing and analysis. Air-dried soils from both sampling years were sieved to 2 mm and large roots were sorted out. Soil Density fractionation Soil was fractionated by density following the method of Swanston et al. (2005), as modified by Marin-Spiotta et al., (2009). Approximately 20 g of air-dried soil was added to centrifuge tubes. Sodium polytungstate (SPT, Na6 [H2W12O40] TC-Tungsten Compounds, Bavaria, Germany) in solution of density 1.85 g cm-3 was added to centrifuge tubes and agitated before centrifuging. The density of the SPT followed previous studies from this and nearby sites to allow direct comparison (Guti\u00e9rrez del Arroyo & Silver, 2018; Hall et al., 2015). Particulate organic matter floating at the surface after centrifugation, the free light fraction (FLF), was aspirated and then rinsed with 100 ml of deionized water 5 times on a 0.8 \u00b5m pore polycarbonate filter (Whatman Nuclepore Track Etch Membrane, Darmstadt, Germany). Rinsed FLF was oven-dried at 65 \u00baC until weight had stabilized. The remainder of the sample was combined with 70 ml of additional SPT and mixed using an electric benchtop mixer (G3U05R, Lightning, New York, NY, USA) at 1700 rpm for 1 min and sonicated in an ice bath for 3 min at 70% pulse (Branson 450 Sonifier, Danbury, CT, USA). Sonication is intended to disrupt soil structure and liberate organic matter that has been occluded in aggregates. The sonicated slurry was centrifuged again, and the light fraction at the surface, the occluded light fraction (OLF), was aspirated, rinsed, and dried using the same method as for the FLF. The remaining soil pellet was considered the heavy fraction (HF), or mineral-associated organic matter fraction. The HF was rinsed by thoroughly mixing with 150 ml of deionized water in the centrifuge tube, centrifuging, and removing the supernatant repeatedly until the fraction had been rinsed 5 times. The rinsed HF was oven-dried at 105 \u00baC until weight stabilized. The average mass recovery was 98%. Soil C and N and \u03b413C Dried bulk and HF soils were homogenized separately using a Spex Ball mill (SPEX Sample Prep Mixer Mill 8000D, Metuchen, NJ). The FLF and OLF were homogenized separately by hand using a mortar and pestle. All homogenized samples were then analyzed at U. C. Berkeley for C and N concentrations on the CE Elantech elemental analyzer (Lakewood, NJ) and for \u03b413C in the Stable Isotope Laboratory at UC Berkeley, using a CHNOS Elemental Analyzer interfaced to an IsoPrime 100 mass spectrometer (Cheadle Hulme, UK), with a long-term external precision of 0.10 %. \u00a0Soil C stocks were calculated by multiplying the C concentrations (%) by the oven-dry mass of bulk soil (< 2 mm) and dividing by depth and the bulk density as measured in 1988 (Silver et al., 1994; Throop et al., 2012). Radiocarbon Homogenized soil samples were combusted to CO2 in sealed glass tubes along with silver (Ag) and copper oxide (CuO) at the Center for Accelerator Mass Spectrometry at Lawrence Livermore National Lab. The CO2 was then graphitized on Fe powder under pressurized hydrogen gas (Vogel et al., 1984). Graphite was pressed into aluminum targets and run on the Compact Accelerator Mass Spectrometer for radiocarbon analysis (Broek et al., 2021). Radiocarbon is reported in \u039414C, following Stuiver & Polach (1977), and calculated based on the fraction of modern isotope composition, corrected for the year of sampling, and corrected for mass-dependent fractionation with observed \u03b413C values of the sample. The compact AMS had an average \u039414C precision of 3.2 %. We report the corrected \u039414C value and \u0394\u039414C, which is calculated as \u039414C of the sample minus \u039414C of the atmosphere, to account for rapidly changing atmospheric \u039414C during the study period. Atmospheric radiocarbon has been decaying nonlinearly since the peak of weapons testing in the 1950s. Radiocarbon signatures in the soil are strongly influenced by the atmospheric D14C signature, making them useful for modeling soil C age and transit time, especially since the 1950s. To compare the contribution of modern C between 1988 and 2018, it is useful to take the difference between soil and atmospheric D14C values, or DD14C, because atmospheric D14C declined between 1988 (98 %) and 2018 (4.4 %) in Northern Hemisphere Zone 2 (Hua et al., 2013). We note that the decline in atmospheric D14C is nonlinear, and thus the DD14C in 2018 soil will be less sensitive to short-term shifts in D14C inputs than the samples from 1988. Carbon age and transit time modeling Transit times and ages of C were modeled with the package \u201cSoilR\u201d (Sierra et al., 2012, 2014) in R, version 4.0.2. The change in C density fractions over time, termed C flow, was modeled using a 3-pool structure with a series flow matrix, under the simplifying assumption that C flows from the litter pool to the FLF, where it is sequentially transferred into the OLF and HF pools (Figure 2). The model structure is depicted in basic form in equation 1, \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (1)\u00a0 dC(t)/dt = Inputs - k*C \u00a0in matrix form with explicit pools in equation 2, \u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (2)\u00a0 dC(t)/dt = [Litter Inputs; 0; 0] + [-kFLF, 0, 0 ; a21,\u00a0-kOLF, 0; 0, a32, -kHRF] * [CFLF; COLF; CHF] where k is the first-order decay constant for each pool, a is the C transfer rate between pools (i.e. a21 is the transfer from FLF (pool 1) to OLF (pool 2) and a32 is the transfer from OLF (pool 2) to HF (pool 3)), and C is the C stock of each pool. The transitTime and systemAge functions within the \u201csoilR\u201d package use this model structure to solve for the distribution of ages (time since entry) of each pool, and the distribution of transit times (times between entry and exit from the bulk soil) (Sierra et al 2016). Distributions of age and transit time were time-independent and did not assume a specific distribution (Sierra et al., 2014, 2017). Figure 2: Hypothesized flow of C in soils. Free light fraction (FLF) C (pink) is either decomposed (at cycling rate -kFLF * FLF) or transferred to the occluded light fraction pool (OLF, blue) with the transfer proportion defined by a21. Carbon transfer between the OLF and heavy fraction (HF, purple) is defined by transfer coefficient a32, and is respired from these pools at cycling rates -kOLF* OLF and -kHF* HF, respectively. Figure adapted from Sierra et al. (2012). Soil D14C and C stock mean and standard deviations from each time point, depth, and fraction were used to constrain the matrix model describing the movement of C through three soil pools and losses of C from each pool. Topography was not a strong predictor of patterns in D14C, C stocks, or C fractions, so samples from all topographies were aggregated for model simulations. The model used mean observed C content in each pool for each depth in 1988 as initial conditions for SOC stocks. Above and belowground litter inputs at 0\u201310 cm were assumed to be 900 g C m-2 in non-hurricane or hurricane recovery years, based on observations from the same site (Liu et al., 2018; Scatena et al., 1996; Silver et al., 1996; Vogt et al., 1996). Inputs to the 10\u201335 cm and 35\u201360 cm depths were estimated using observations of live fine roots on the surface and typical root distribution in the forest (Silver & Vogt, 1993). Total root input is approximately threefold the input of fine roots alone (McCormack et al., 2015; Yaffar & Norby, 2020), and live fine roots in the 0\u201310 cm depth had a mean biomass of 80 - 250 g C m-2 \u00a0(Hall et al., 2015), suggesting that total root C inputs of approximately 450 g C m-2 to the surface would be well within the expected range. Root inputs below 0\u201310 cm were estimated assuming that inputs follow the typical distribution of root biomass in Puerto Rican tropical forests, with 60\u201370% of root biomass in 0\u201310 cm, an additional 20-30% of biomass in 10\u201335 cm (~135 g C m-2\u00ad), and 5\u20138% of biomass is in the 35\u201360 cm depth (~40 g C m-2\u00ad) (Silver & Vogt, 1993; Yaffar & Norby, 2020). The model was parameterized under two scenarios for each depth: 1) constant inputs, assuming a steady-state undisturbed forest, and 2) hurricane inputs, which simulated the input fluxes from defoliation during the three major hurricanes, followed by a subsequent reduction in litter inputs and then litterfall increasing linearly to pre-hurricane inputs over 6 years (Scatena et al., 1996; Silver et al., 1996; Vogt et al., 1996). Hurricane inputs were imposed as an additional pulse of litter inputs to each depth interval, declining with depth. \u00a0The 0\u201310 cm interval received 100% of the surface input pulse, the 10\u201335 cm depth received a pulse of root inputs equivalent to 30% of the surface input pulse, and the 35\u201360 cm depth received root inputs equal to 10% of the surface input pulse. Surface litter pulses under hurricanes were specified according to measured litterfall values and were 42.5 g C m-2\u00ad to the surface in 1989 (Hurricane Hugo) and 1998 (Hurricane Georges) (Scatena et al., 1993; Silver et al., 1996) and 1611 g C m-2 \u00a0in 2017 (Hurricanes Irma and Maria) (Liu et al. 2018a). The same soil D14C and C stock observations were used to constrain the model under each scenario, with only the input regime varying. Parameters of the transfer matrix (-k\u00ad\u00adFLF, -k\u00ad\u00adOLF, -k\u00ad\u00adHF, a21, a32) were constrained using a cost function to accept or reject potential parameter sets over 1000 iterations, based on observed D14C and C stock means and standard errors from both time points (1988 and 2018). A Markov chain Monte Carlo (MCMC) simulation initialized with cost-optimized parameters was run to assimilate observed data and optimize parameter choices to the observations using function modMCMC() from R package \u201cFME\u201d (Sierra et al., 2014; Soetaert & Petzoldt, 2010). The MCMC was iterated over at least 20,000 simulations or until parameter solutions converged according to the trace, which was over 100,000 iterations at the 35\u201360 cm depth. The first half of the iterations was considered the burn-in period before the chain started to converge near an equilibrium, and these iterations were discarded in calculations of optimal parameters. The model output for the surface soils of the HF pool was validated using published radiocarbon values from the mineral-associated fraction (the only fraction analyzed) of samples from the site taken in 2012 (Hall et al., 2015).\u00a0 Bulk and pool soil C age and transit time density distributions and mean values were calculated using the systemAge() and transitTime() functions from the \u201cSoilR\u201d package. Mean density distributions were calculated using the mean parameter set given from the MCMC analysis. Standard deviation from the mean was calculated using the systemAge() and transitTime() functions on 200 sets of five parameters selected randomly within one standard deviation of the mean of each parameter given as output from the MCMC. Lower and upper limits of SOC ages and transit times were calculated using the upper and lower ranges of these iterations. Statistics Statistics were run in R, version 4.0.2 (R Core Team, 2020). The statistical model selection followed the recommendations of Zuur et al (2009). Statistical models were chosen using a linear mixed effects model in package \u201clme4\u201d, with random slopes accounting for the influence each core, or sampling site, had on the response variable values as they varied with depth. This random effect of the core site on the depth effect was evaluated using a restricted maximum likelihood approach and was included in the initial evaluation of all model comparisons. Linear mixed effect models included year, topographic position, depth, and interactions as fixed factors, and the depth effect of each core as a random factor for each of the response variables: C concentration, N concentration, d13C, DD14C. In evaluations of some response variables with AIC and BIC criteria, the random effect no longer enhanced the model, and model comparison proceeded using ANOVAs of linear models without random effects. Topographic effects on C concentrations are discussed in the supplemental information. Model assumptions were evaluated using the check_model function in R package \u201cperformance\u201d, to check for multicollinearity, normality of residuals, homoscedasticity, homogeneity of variance, influential observations, and normality of random effects. In the cases when random effects were significant (bulk soil d13C and DD14C, FLF DD14C and HF C and N concentrations), fixed effects were chosen using ANOVA of subsequent models using maximum likelihood estimation, with the random effects held constant. Once fixed effects were established, the model was re-fitted using a restricted maximum likelihood approach to report model estimates, and an ANOVA was run to determine the significance of the response variable. In all cases, P-values were estimated using Tukey\u2019s honest significant post-hoc test to assess significant differences between variables, in the package \u201cagricolae\u201d in R, and contrasts and standard errors of contrasts were estimated using lsmeans() function in package \u201clsmeans\u201d in R. Values of\u00a0P < 0.10 were reported as significant unless otherwise specified. The topographic position was not a significant predictor for most variables, so results are reported as means aggregated across positions.", "keywords": ["soil organic carbon", "Transit time", "Tropical forest soil", "FOS: Earth and related environmental sciences", "Soil R", "density fractions", "Radiocarbon"], "contacts": [{"organization": "Mayer, Allegra", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5061/dryad.0k6djhb5k"}, {"rel": "self", "type": "application/geo+json", "title": "10.5061/dryad.0k6djhb5k", "name": "item", "description": "10.5061/dryad.0k6djhb5k", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5061/dryad.0k6djhb5k"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-04-01T00:00:00Z"}}, {"id": "10.5061/dryad.jk939fc", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:23:15Z", "type": "Dataset", "title": "Data from: Dynamics of deep soil carbon - insights from 14C time series across a climatic gradient", "description": "unspecifiedData_and_code_Van_der_Voort_et_al_2019_BiogeosciencesThis zip file contains all the code and data accompanying the paper: Dynamics of deep soil carbon - insights from 14C time series across a climatic gradient (Van der Voort et al., Biogeosciences, 2019). The data of each figure can be found in the excel file. The MatLab codes referenced in the paper can also be found in the zip file. They are thoroughly commented so that users can easily re-use it.Time_Series_Data_Repo_Folder_Dryad.zip", "keywords": ["2. Zero hunger", "Soil science", "soil organic carbon", "1994-2014", "13. Climate action", "15. Life on land", "time series", "Biogeosciences", "Radiocarbon"], "contacts": [{"organization": "van der Voort, Tessa Sophia, Mannu, Utsav, Hagedorn, Frank, McIntyre, Cameron, Walthert, Lorenz, Schleppi, Patrick, Haghipour, Negar, Eglinton, Timothy I.,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5061/dryad.jk939fc"}, {"rel": "self", "type": "application/geo+json", "title": "10.5061/dryad.jk939fc", "name": "item", "description": "10.5061/dryad.jk939fc", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5061/dryad.jk939fc"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-08-23T00:00:00Z"}}, {"id": "10.5281/zenodo.10037187", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:23:42Z", "type": "Dataset", "title": "Dataset to Schiedung et al. (2024): Millennial-aged pyrogenic carbon in high-latitude mineral soils", "description": "Dataset to Schiedung et al. (2024, Communications Earth & Environment): Pyrogenic Carbon is Aged at Millennial Scale in High-Latitude Mineral Soils DOI: 10.1038/s43247-024-01343-5 This repository includes the following files:\u00a0 dd_all.csv - Includes all data for the individual samples that are presented in the manuscript. Var_names_dd_all.csv - Describes all variables in dd_all with corresponding unit\u00a0 dd_site_average.csv - Includes all data that has been determined on composite samples for each site or the average of all samples per site\u00a0 Var_names_dd_site_average.csv\u00a0 -\u00a0 Describes all variables in dd_site_average.csv with corresponding unit All .csv use ',' as separator.\u00a0 This data set is also connected to Schiedung et al. (2022, Catena \u00a0https://doi.org/10.1016/j.catena.2022.106194 ) and the corresponding repository: https://zenodo.org/records/10609291", "keywords": ["Soil", "Pyrogenic Carbon", "Permafrost", "Organic carbon", "Radiocarbon"]}, "links": [{"href": "https://doi.org/10.5281/zenodo.10037187"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.10037187", "name": "item", "description": "10.5281/zenodo.10037187", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.10037187"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-04-05T00:00:00Z"}}, {"id": "10.5281/zenodo.10126878", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:23:43Z", "type": "Dataset", "title": "NEON Soil Radiocarbon Data", "description": "Radiocarbon measurements for megapit profiles from 17 NEON sites: 'BART' 'CLBJ' 'DSNY' 'JERC' 'NIWO' 'ONAQ' 'RMNP' 'SCBI' 'SOAP' 'TALL' 'UKFS' 'UNDE' 'WREF' 'OSBS' 'HARV' 'CPER' 'DCFS' Updated carbon concentrations missing from subset of samples and regularized 'archiveID' strings to facilitate joins with other NEON megapit data. The 'archiveID' field can be used to match data in the 'perarchivesample' tables from NEON.", "keywords": ["radiocarbon", "NEON"], "contacts": [{"organization": "Beem-Miller, Jeffrey, Sierra, Carlos A.,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.10126878"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.10126878", "name": "item", "description": "10.5281/zenodo.10126878", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.10126878"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-09-20T00:00:00Z"}}, {"id": "10.5281/zenodo.10537332", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:23:46Z", "type": "Dataset", "title": "Moisture and temperature effects on the radiocarbon signature of respired carbon dioxide to assess stability of soil carbon in the Tibetan Plateau", "description": "Open AccessThis study was developed as part of the International Research Training Group (GRK 2309/1) Geo-ecosystems in transition on the Tibetan Plateau' (TransTiP) funded by the Deutsche Forschungsgemeinschaft (DFG).", "keywords": ["Radiocarbon (14C)", "Age", "Soil organic matter (SOM)", "Transit time", "Peatland", "Qinghai-Tibetan Plateau (QTP)", "Incubation", "Grassland"], "contacts": [{"organization": "Tangarife-Escobar, Andres, Guggenberger, Georg, Feng, Xiaojuan, Dai, Guohua, Urbina-Malo, Carolina, Azizi-Rad, Mina, Sierra, Carlos,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.10537332"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.10537332", "name": "item", "description": "10.5281/zenodo.10537332", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.10537332"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-01-20T00:00:00Z"}}, {"id": "10.5281/zenodo.10952030", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:23:58Z", "type": "Dataset", "title": "Radiocarbon Isotopic Disequilibrium Shows Little Incorporation of New Carbon in Mineral Soils of a Boreal Forest Ecosystem", "description": "Files for the manuscript \u201cRadiocarbon Isotopic Disequilibrium Shows Little Incorporation of New Carbon in Soils and Fast Cycling of a Boreal Forest Ecosystem\u201d \u00a0 1. \u201cRaw_Data\u201d folder contains the files in .xlsx: - Lab_Atmospheric_Samples: D14C results from ambient air at the sampled heights. - Lab_Soil_Respiration: D14C results with date and integration time for the FFSR sampling\u00a0 campaign. - Lab_Solid_Samples:\u00a0 D14C and TOC results for soil, vegetation, roots, fungi and incubation samples.", "keywords": ["Sweden", "Soil sciences", "climate change", "soil organic matter", "carbon", "radiocarbon", "carbon dioxide", "boreal forest", "Climatic changes"], "contacts": [{"organization": "Tangarife Escobar, Andres, Guggenberger, Georg, Feng, Xiaojuan, Mu\u00f1oz, Estefania, Chanca, Ingrid, Peichl, Matthias, Smith, Paul, Sierra, Carlos,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.10952030"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.10952030", "name": "item", "description": "10.5281/zenodo.10952030", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.10952030"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-04-10T00:00:00Z"}}, {"id": "10.5281/zenodo.15077441", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:24:44Z", "type": "Dataset", "created": "2025-04-24", "title": "Permafrost thaw reverses soil carbon age profiles and extends transit time in an Arctic tundra soil", "description": "unspecifiedA vertically-resolved model was developed and optimized against radiocarbon (14C) data from a 25-year snow manipulation experiment to quantify how deeper snow affects soil carbon age, transit time, and redistribution in Arctic permafrost.", "keywords": ["soil organic carbon", "Age", "Carbon dioxide", "transit time", "radiocarbon", "Permafrost", "Arctic ecosystem", "Carbon", "Alaska"], "contacts": [{"organization": "Tangarife Escobar, Andres, Pedron, Shawn Alexander, Czimczik, Claudia I., Metzler, Holger, Gonz\u00e1lez Sosa, Maximiliano, Welker, Jeffrey, Guggenberger, Georg, Sierra, Carlos,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.15077441"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.15077441", "name": "item", "description": "10.5281/zenodo.15077441", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.15077441"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2025-03-24T00:00:00Z"}}, {"id": "10.5281/zenodo.15282598", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:24:48Z", "type": "Dataset", "created": "2020-01-01", "title": "Datasets for Maier et al., Parent material geochemistry \u2013 and not plant biomass \u2013 as the key factor shaping soil organic carbon stocks in European alpine grasslands", "description": "the uploaded datasets entail the following files: Alpine_SOC_complete: excel sheets including data and metadata of all soil and plant biomass observations. used to run statistical analyses and data visualization for figures in the publication. includes 1) plant biomass variables, 2) soil physiochemical and organic variables Alpine_SOC_F14C: excel sheets including data and metadata of sampling sites' fraction modern radiocarbon (F14C) Alpine_SOC_excl_dolomite: excel sheets including the data and metadata needed for the running of the soil organic carbon prediction models in the publication", "keywords": ["Soil Organic Carbon", "Alpine soil", "Biogeochemistry", "Radiocarbon", "Carbon Cycle"], "contacts": [{"organization": "Maier, Annina, Maier, Annina, Macfarlane, Maria,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.15282598"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.15282598", "name": "item", "description": "10.5281/zenodo.15282598", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.15282598"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2025-04-25T00:00:00Z"}}, {"id": "10.5281/zenodo.16980274", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:25:06Z", "type": "Dataset", "title": "Ancient soil organic carbon quantification in worldwide soils", "description": "These are the files for the paper in press for Global Change Biology entitled ' Soil carbon dynamics reshaped by ancient carbon quantification'. The doi of this paper will be provided once the paper will be published. In this paper we applied a mixing linear equation to 313 soils worldwide from radiocarbon databases to estimate the ancient OC (radiocarbon-free) contained in these soils. Beyond the calculated contribution of this ancient OC to soil organic carbon (SOC) in top, sub and deepsoils, we revisited the mean 14C age of SOC and consequently the soil carbon dynamics. The \u201cCopard et al-GCB-data.xls\u201d file is split in two table. Table 1 is referred to the soil 14C ISRaD and LSCE database and additional variables we calculated in order to know the ancient organic carbon mass concentration in a considered soil profile and its contribution to the soil organic carbon for each soil layer. Some of these variables were either calculated by using the equations given in the associated article published in Global Change Biology (Copard et al) or derived from literature associated to the reference listed in the two databases (ISRaD and LSCE). Table 2 is identical to table 1 with additional variables devoted to loess formations, as the age of the loess deposit (BP), the organic carbon concentration from loess, and additional references with their doi where these specific variables were found. The Copard et al-GCB-readme.xls file consists in a summary file with your data explaining the variables used and entries in each row and column of the data file. This includes units of measurement, a description of each variable and explanation of how the files relate to each other.", "keywords": ["soil organic carbon", " radiocarbon", " carbon turnover time", " meta-analysis", " parent material", " radiocarbon-free organic carbon"], "contacts": [{"organization": "copard, yoann", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.16980274"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.16980274", "name": "item", "description": "10.5281/zenodo.16980274", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.16980274"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2025-08-28T00:00:00Z"}}, {"id": "10.5281/zenodo.16965776", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:25:06Z", "type": "Dataset", "created": "2025-04-24", "title": "Permafrost thaw reverses soil carbon age profiles and extends transit time in an Arctic tundra soil", "description": "unspecifiedA vertically-resolved model was developed and optimized against radiocarbon (14C) data from a 25-year snow manipulation experiment to quantify how deeper snow affects soil carbon age, transit time, and redistribution in Arctic permafrost.", "keywords": ["soil organic carbon", "Age", "Carbon dioxide", "transit time", "radiocarbon", "Permafrost", "Arctic ecosystem", "Carbon", "Alaska"], "contacts": [{"organization": "Tangarife Escobar, Andres, Pedron, Shawn Alexander, Czimczik, Claudia I., Metzler, Holger, Gonz\u00e1lez Sosa, Maximiliano, Welker, Jeffrey, Guggenberger, Georg, Sierra, Carlos,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.16965776"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.16965776", "name": "item", "description": "10.5281/zenodo.16965776", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.16965776"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2025-03-24T00:00:00Z"}}, {"id": "10.5281/zenodo.2613911", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:25:12Z", "type": "Dataset", "title": "International Soil Radiocarbon Database v1.0", "description": "Open AccessThis version of ISRaD data corresponds to our manuscript submitted to the Journal Earth Systems Science Data", "keywords": ["13. Climate action", "biogeochemistry", "carbon cycle", "radiocarbon", "soils"]}, "links": [{"href": "https://doi.org/10.5281/zenodo.2613911"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.2613911", "name": "item", "description": "10.5281/zenodo.2613911", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.2613911"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-03-28T00:00:00Z"}}, {"id": "10.5281/zenodo.2613910", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:25:12Z", "type": "Dataset", "title": "International Soil Radiocarbon Database v1.0", "description": "Open AccessThis version of ISRaD data corresponds to our manuscript submitted to the Journal Earth Systems Science Data", "keywords": ["13. Climate action", "biogeochemistry", "carbon cycle", "radiocarbon", "soils"]}, "links": [{"href": "https://doi.org/10.5281/zenodo.2613910"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.2613910", "name": "item", "description": "10.5281/zenodo.2613910", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.2613910"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-03-28T00:00:00Z"}}, {"id": "10.5281/zenodo.3832031", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:25:16Z", "type": "Dataset", "title": "Radiocarbon content of carbon dioxide, methane, dissolved organic carbon and particulate organic carbon from the northern permafrost region and other studies", "description": "The dataset includes 14C measurements of CO2, CH4, DOC and POC mostly from the northern permafrost region. Some other studies are included from sites not underlained by permafrost. The dataset focuses on 14C measurements of gaseous soil emissions and waterborne ecosystem C fluxes but the database also included C forms belowground, such as soil gases and pore water DOC.", "keywords": ["13. Climate action", "15. Life on land", "radiocarbon", " permafrost", " carbon dioxide", " methane", " dissolved organic carbon", " particulate organic carbon", " DOC", " POC", " thermokarst", " thaw"], "contacts": [{"organization": "Estop-Aragon\u00e9s, Cristian", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.3832031"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.3832031", "name": "item", "description": "10.5281/zenodo.3832031", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.3832031"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-05-18T00:00:00Z"}}, {"id": "10.5281/zenodo.4281013", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:25:18Z", "type": "Dataset", "title": "Roots Carbon Dynamics in Temperate forest roots, Thuringia, Germany", "description": "Open AccessThese files contain radiocarbon, d13C, NSC concentrations, and CO2 efflux rates measured for aspen (Populus tremula hybrids) roots collected during 2018 growing season in the Gro\u00dfer Hermannsberg Mountain, Germany (50\u00b042\u201950\u2019\u2019 N, 10\u00b036\u201913\u2019\u2019 E, 616 m a.s.l). Coarse (> 2 mm) and fine (2 \u2264 mm) roots collected from three 'treatments': before stem girdling (Pre-girdling), ~3 months after girdling (Girdling) and ~3 months after girdling but in un-girdled trees (Control). The files with the relevant results: '13C', '14C', 'CO2_efflux', 'NSC'. Few roots from the 'Pre-girdling' treatment were incubated for respiration measurements 7 d after harvest. The files with the relevant results: 'Repeated_incubations_isotopes', 'Repeated_incubations_fluxes'. Results of incubations used for Q10 calculations presented in the file 'CO2_efflux_Q10'. Temperature and rainfall in the site during 2018 growing season are presented in the file 'Field_temperature_rainfall'. Results used to reconstruct local atmospheric D14C-CO2 record are presented in the file 'Local_atmospheric_CO2_D14C'. The file 'Metadata' contains information about the headers in the other files.", "keywords": ["tree roots", "d13C", "15. Life on land", "storage dynamics", "nonstructural carbohydrates", "radiocarbon (14C)", "respiration"]}, "links": [{"href": "https://doi.org/10.5281/zenodo.4281013"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.4281013", "name": "item", "description": "10.5281/zenodo.4281013", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.4281013"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-11-24T00:00:00Z"}}, {"id": "10.5281/zenodo.4281012", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:25:18Z", "type": "Dataset", "title": "Roots Carbon Dynamics in Temperate forest roots, Thuringia, Germany", "description": "Open AccessThese files contain radiocarbon, d13C, NSC concentrations, and CO2 efflux rates measured for aspen (Populus tremula hybrids) roots collected during 2018 growing season in the Gro\u00dfer Hermannsberg Mountain, Germany (50\u00b042\u201950\u2019\u2019 N, 10\u00b036\u201913\u2019\u2019 E, 616 m a.s.l). Coarse (> 2 mm) and fine (2 \u2264 mm) roots collected from three 'treatments': before stem girdling (Pre-girdling), ~3 months after girdling (Girdling) and ~3 months after girdling but in un-girdled trees (Control). The files with the relevant results: '13C', '14C', 'CO2_efflux', 'NSC'. Few roots from the 'Pre-girdling' treatment were incubated for respiration measurements 7 d after harvest. The files with the relevant results: 'Repeated_incubations_isotopes', 'Repeated_incubations_fluxes'. Results of incubations used for Q10 calculations presented in the file 'CO2_efflux_Q10'. Temperature and rainfall in the site during 2018 growing season are presented in the file 'Field_temperature_rainfall'. Results used to reconstruct local atmospheric D14C-CO2 record are presented in the file 'Local_atmospheric_CO2_D14C'. The file 'Metadata' contains information about the headers in the other files.", "keywords": ["tree roots", "d13C", "15. Life on land", "storage dynamics", "nonstructural carbohydrates", "radiocarbon (14C)", "respiration"]}, "links": [{"href": "https://doi.org/10.5281/zenodo.4281012"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.4281012", "name": "item", "description": "10.5281/zenodo.4281012", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.4281012"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-11-24T00:00:00Z"}}, {"id": "10.5281/zenodo.5652048", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:25:23Z", "type": "Dataset", "title": "Transport of Particulate Organic Carbon in The Huanghe: Insights from Lateral And Vertical Heterogeneity in a River Cross-section", "description": "The Huanghe (Yellow River), one of the largest turbid river systems in the world, has long been recognized as a major contributor of suspended particulate matter (SPM) to the ocean. However, over the last few decades, the SPM export flux of the Huanghe has decreased over 90% due to the high management, impacting the global export of particulate organic carbon (POC). To better constrain sources and modes of transport of POC beyond the previously investigated transportation of POC near the channel surface, SPM samples were for the first time collected over a whole channel cross-section in the lower Huanghe. Riverine SPM samples were analyzed for particle size and major element contents, as well as for POC content and dual carbon isotopes (13C and 14C). The results show clear vertical and lateral heterogeneity of SPM physical and chemical characteristics within the river cross section, with for example finer SPM carrying more POC with higher 14C activity near the surface and the right bank. Notably, we discuss how bank erosion in the alluvial plain is likely to generate lateral heterogeneity in POC composition. The Huanghe POC is millennial-aged (4,020 \u00b1 500 radiocarbon years), dominated by organic carbon (OC) from the biosphere, while the lithospheric fraction reaches up to ca. 33%. The mobilization of aged and refractory OC from deeper soil horizons of the loess-paleosol sequence through erosion in the Chinese Loess Plateau is an important mechanism contributing to fluvial POC in the Huanghe drainage basin. The involvement of this OC fraction has significance for the regional and global carbon cycles, especially regarding its final fate in the estuary. Altogether, this study sheds light on the mechanism of fluvial transfer of POC and corresponding impacts on the carbon cycle in large river systems strongly perturbed by anthropogenic activities.", "keywords": ["particulate organic carbon", "13. Climate action", "Huanghe", "bank erosion", "radiocarbon", "depth profile sampling", "14. Life underwater", "15. Life on land", "6. Clean water"], "contacts": [{"organization": "Yutian, Ke, Calmels Damien, Bouchez Julien, Massault Marc, Chetelat Benjamin, Noret Aur\u00e9lie, Hongming, Cai, Jiubin, Chen, Gaillardet J\u00e9r\u00f4me, Quantin C\u00e9cile,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.5652048"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.5652048", "name": "item", "description": "10.5281/zenodo.5652048", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.5652048"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-06-06T00:00:00Z"}}, {"id": "10.5281/zenodo.5736535", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:25:23Z", "type": "Dataset", "title": "Supporting data for manuscript: Beyond Bulk", "description": "Open AccessWe used soil density fraction data from The International Soil Radiocarbon Database (ISRaD v. 1.1.2 Lawrence et al., 2020; www.soilradiocarbon.org). ISRaD is an online repository for environmental radiocarbon data with a specific emphasis on soils and soil fractions. We utilized a subset of ISRaD data comprising measurements of radiocarbon (persistence), organic C concentration (abundance), or the proportion of organic C in the mineral-associated fraction (distribution) made on soil density fractions for the current analysis. Radiocarbon data are reported in units of \ufffd\ufffd14C (\ufffd\ufffd\ufffd) normalized to account for the year of sampling (Shi et al., 2020) (see below). In studies that employed sequential density separation (isolation of multiple free light, occluded light, and heavy fractions for the same sample), the multiple fractions were combined by taking a mass-weighted average for C abundance and C-weighted average for \ufffd\ufffd14C values. C distribution among density fractions was normalized to sum to 100%. Overall, our meta-analysis included data from 52 studies. In addition to C measurements, ISRaD compiles ancillary data regarding site and sample characteristics that were either provided directly in the associated published works or provided as supplementary information from manuscript authors. When variables of interest were not available directly through ISRaD, these variables were populated through utilization of geolocated databases (see supplemental materials in associated published manuscript).", "keywords": ["soil fractions", " radiocarbon", " persistence", " soil organic matter", " soil carbon", " climate change", " terrestrial carbon cycle", "15. Life on land"], "contacts": [{"organization": "Heckman, Katherine A, Pries, Caitlin EH, Lawrence, Corey R, Rasmussen, Craig, Crow, Susan E, Hoyt, Alison M, von Fromm, Sophie F, Shi, Zheng, Stoner, Shane, McGrath, Casey, Beem-Miller, Jeffrey, Berhe, Asmeret A, Blankinship, Joseph C, Keiluweit, Marco, Mar\u00edn-Spiotta, Erika, Monroe, J Grey, Plante, Alain F, Sierra, Carlos A, Thompson, Aaron, Wagai, Rota,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5281/zenodo.5736535"}, {"rel": "self", "type": "application/geo+json", "title": "10.5281/zenodo.5736535", "name": "item", "description": "10.5281/zenodo.5736535", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5281/zenodo.5736535"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-11-29T00:00:00Z"}}, {"id": "21.11116/0000-0003-863B-4", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-03T16:27:51Z", "type": "Journal Article", "created": "2019-01-04", "title": "14C\u2010Free Carbon Is a Major Contributor to Cellular Biomass in Geochemically Distinct Groundwater of Shallow Sedimentary Bedrock Aquifers", "description": "Abstract

Despite the global significance of the subsurface biosphere, the degree to which it depends on surface organic carbon (OC) is still poorly understood. Here, we compare stable and radiogenic carbon isotope compositions of microbial phospholipid fatty acids (PLFAs) with those of in situ potential microbial C sources to assess the major C sources for subsurface microorganisms in biogeochemical distinct shallow aquifers (Critical Zone Exploratory, Thuringia Germany). Despite the presence of younger OC, the microbes assimilated 14C\uffe2\uff80\uff90free OC to varying degrees; ~31% in groundwater within the oxic zone, ~47% in an iron reduction zone, and ~70% in a sulfate reduction/anammox zone. The persistence of trace amounts of mature and partially biodegraded hydrocarbons suggested that autochthonous petroleum\uffe2\uff80\uff90derived hydrocarbons were a potential 14C\uffe2\uff80\uff90free C source for heterotrophs in the oxic zone. In this zone, \uffce\uff9414C values of dissolved inorganic carbon (\uffe2\uff88\uff92366\uffc2\uffa0\uffc2\uffb1\uffc2\uffa018\uffe2\uff80\uffb0) and 11MeC16:0 (\uffe2\uff88\uff92283\uffc2\uffa0\uffc2\uffb1\uffc2\uffa032\uffe2\uff80\uffb0), an important component in autotrophic nitrite oxidizers, were similar enough to indicate that autotrophy is an important additional C fixation pathway. In anoxic zones, methane as an important C source was unlikely since the 13C\uffe2\uff80\uff90fractionations between the PLFAs and CH4 were inconsistent with kinetic isotope effects associated with methanotrophy. In the sulfate reduction/anammox zone, the strong 14C\uffe2\uff80\uff90depletion of 10MeC16:0 (\uffe2\uff88\uff92942\uffc2\uffa0\uffc2\uffb1\uffc2\uffa022\uffe2\uff80\uffb0), a PLFA common in sulfate reducers, indicated that those bacteria were likely to play a critical part in 14C\uffe2\uff80\uff90free sedimentary OC cycling. Results indicated that the 14C\uffe2\uff80\uff90content of microbial biomass in shallow sedimentary aquifers results from complex interactions between abundance and bioavailability of naturally occurring OC, hydrogeology, and specific microbial metabolisms.We evaluated global soil organic carbon (SOC) stocks and turnover time predictions from a global land model (ELMv1\uffe2\uff80\uff90ECA) integrated in an Earth System Model (E3SM) by comparing them with observed soil bulk and \uffce\uff9414C values around the world. We analyzed observed and simulated SOC stocks and \uffce\uff9414C values using machine learning methods at the Earth System Model grid cell scale (~200\uffc2\uffa0km). In grid cells with sufficient observations, the model provided reasonable estimates of soil carbon stocks across soil depth and \uffce\uff9414C values near the surface but underestimated \uffce\uff9414C at depth. Among many explanatory variables, soil albedo index, soil order, plant function type, air temperature, and SOC content were major factors affecting predicted SOC \uffce\uff9414C values. The influences of soil albedo index, soil order, and air temperature were primarily important in the shallow subsurface (\uffe2\uff89\uffa430\uffc2\uffa0cm). We also performed sensitivity studies using different vertical root distributions and decomposition turnover times and compared to observed SOC stock and \uffce\uff9414C profiles. The analyses support the role of vegetation in affecting soil carbon turnover, particularly in deep soil, possibly through supplying fresh carbon and degrading physical\uffe2\uff80\uff90chemical protection of SOC via root activities. Allowing for grid cell\uffe2\uff80\uff90specific rooting and decomposition rates substantially reduced discrepancies between observed and predicted \uffce\uff9414C values and SOC content. Our results highlight the need for more explicit representation of roots, microbes, and soil physical protection in land models.