全球负地形（洼地、湿地、淤地坝、水库和湖泊）单元土壤有机碳储量研究进展

… Soil erosion contributes to the removal of soil organic carbon (SOC) from cultivated soils and its entrapment in terrestrial depressions. … The SOC storage and dynamics were studied in …

Soil erosion in loess landscapes results in soil organic carbon (SOC) redistribution and storage in SOC pools. Understanding the SOC dynamics is important because changes in the SOC stocks may have impacts on global climate change. However, the topographic‐related patterns controlling SOC storage are not well understood. Closed depressions are natural landforms in loess landscapes and preserve buried Holocene soils and SOC‐rich colluvia resulting from soil erosion and are SOC pools. The aim of this study was to quantify the impact of natural closed depressions on SOC storage in the loess landscape of the Nałęczów Plateau. Buried Holocene soils and colluvial sediments infilling five representative closed depressions were documented and the SOC stocks were calculated. Using GIS analysis SOC from all closed depressions was calculated and mapped. Between 13.5 and 229.78 Mg of SOC are in the entire soil profiles of the studied closed depressions, 10%–21% of the SOC stock is in the topsoils. The SOC stock in all closed depressions of the study area reaches 172.09–265.19 Mg ha−1 and in the soil cover outside the closed depressions is 51.20–105.40 Mg ha−1. SOC from closed depressions varies spatially and increases the SOC stock at regional scale by 0.1–90 Mg ha−1. For about 21% of the study area, the SOC from closed depressions increases the SOC stock in the agricultural landscape by more than 10% (up to 60%). This study highlights the importance of closed depressions for SOC storage and provides a better understanding of its spatial distribution at the regional scale.

This study aimed to determine the spatial distribution of total soil organic carbon (TSOC) content in surface soils in the karst ecosystem located in the Mediterranean region of Turkey. Land use types and depression areas were determined using Landsat8 and Shuttle Radar Topography Mission (SRTM) data, respectively. Topsoil samples (0-10 cm) were collected in 108 sites and analysed for soil pH, SOC, bulk density (BD), total nitrogen content (N) and particle size distribution. The exponential model was the best model to describe SOC contents, stable model for BD and circular model for TSOC. The SOC content in different land uses ranked as forest (4.10%) > rangeland (2.60%) > cropland (1.41%) areas. Mean TSOC content was identified as 27.22 MgCha−1 in non-depressed areas and 48.71 MgCha−1 in depressed areas. TSOC dramatically changed from none-depressed areas to depressed areas were identified in cropland (ΔTSOCcropland = 68.05%). Forest areas were more stable in view of the change of carbon sequestration compared to the other areas (ΔTSOCforest3 = 28.24%). Depression areas play very important role in terms of carbon storage capacity in the Karst ecosystem.

… The highest C stock was observed in stone cave, with the value of 21.06 kg·m −… soil surface with the lowest C stock. The C content of LF and OF decreased at rocky soil surface and soil …

… of organic matter in permafrost regions were reworked and deposited in thermokarst depressions formed as permafrost thawed and the ground subsided due to loss of ground ice …

… SOC spatial distribution in karst landforms may be due to the higher rock exposure rate, leading to soil accumulation in localized depressions. This environmental background results in …

… Water-eroded soil usually deposits in depression at the footslope or toeslope of a landscape and erosional/depositional history at each landscape position influences the SOC dynamics …

… Soil carbon models are being updated to reflect emerging awareness of the … of depressions as soil C sinks; previous models frequently underestimated SOC gains in depressions and …

It is essential to assess the soil organic carbon pool (SOCP) in dry environments to apply appropriate management techniques that address sustainable development. A significant opportunity for sustaining agricultural output and reducing climate change is the storage of soil organic carbon in agricultural soil. The goal of this study was to measure the spatial variability of SOCP content, and determine the effects of soil texture, changes in land use, and land cover on SOCP in surface soil samples. The study additionally investigated the relationships between SOCP and other characteristics, including the normalized vegetation index (NDVI) and land surface temperature (LST), as well as the effects of increasing soil organic carbon on the amount of greenhouse gases. To accomplish this goal, 45 soil surface samples were collected to a depth of 30 cm at the Fayoum depression in Egypt, and analyzed. The soil samples were representative of various soil textures and land uses. The average SOCP concentration in cultivated regions is 32.1 and in bare soils it is 6.5 Mg ha−1, with areas of 157,112.94 and 16,073.27 ha, respectively. According to variances in soil textures, sandy soils have the lowest SOCP (1.8 Mg ha−1) and clay loam soils have the highest concentrations (49 Mg ha−1). Additionally, fruit-growing regions have the greatest SOCP values and may therefore be better suited for carbon sequestration. The overall average SOCP showed 32.12 Mg C ha−1 for cultivated areas. A rise in arable land was accompanied by a 112,870.09 Mg C rise in SOCP. With an increase in soil organic carbon, stored carbon dioxide emissions (greenhouse gases) would be reduced by 414,233.24 Mg CO2. We should consider improving fertilization, irrigation methods, the use of the multiple cropping index, decreasing desertion rates, appropriate crop rotation, and crop variety selection. The research highlights the significance of expanding cultivated areas towards sustainable carbon sequestration and the climate-change-mitigation potential.

In the mitigation strategies of climate change, improving soil carbon storage is considered as one of the main tasks to enhance agricultural sustainability and sequester atmospheric carbon dioxide. Agricultural patterns have been changing significantly and causing many impacts on soil organic carbon (SOC) storage in the upper Vietnamese Mekong Delta (VMD). Therefore, this study aims to evaluate how typical agricultural pattern changes are affecting SOC by estimating the SOC stock and identifying the correlation with soil physic-chemical properties. Soil samples were collected in both depths of 0-20 cm and 20-50 cm and analyzed physic-chemical properties such as soil texture, bulk density, pH KCl , EC and SOC. In topsoil layers, the SOC stock of the wetland forest was the highest in the opened depression of floodplain (24.42±1.38 kg C m -2 ; p< 0.05) while that of paddy rice was the richest at depth of 20-50 cm (27.69±2.97 kg C m -2 ; p< 0.05). In other agro-ecological areas, SOC stock in croplands was lower than forest and grassland in topsoil layer, especially in mountainous areas. SOC stock correlated positively with SOC content, clay, bulk density, and EC ( p< 0.05) but had a negative correlation with sand and pH KCl ( p< 0.05). The decrease in SOC stock in dry cultivating patterns indicated the impact of agricultural management practices and soil fertility on SOC storage. Thus, improving SOC stock

… In an ecosystem, soil organic matter (SOM) is an important indicator of soil fertility and soil quality. Accurate information about the spatial variation of SOM is critical for sustainable soil …

Wetland soils contain some of the highest stores of soil carbon in the biosphere. However, there is little understanding of the quantity and distribution of carbon stored in our remaining wetlands or of the potential effects of human disturbance on these stocks. Here we use field data from the 2011 National Wetland Condition Assessment to provide unbiased estimates of soil carbon stocks for wetlands at regional and national scales. We find that wetlands in the conterminous United States store a total of 11.52 PgC, much of which is within soils deeper than 30 cm. Freshwater inland wetlands, in part due to their substantial areal extent, hold nearly ten-fold more carbon than tidal saltwater sites—indicating their importance in regional carbon storage. Our data suggest a possible relationship between carbon stocks and anthropogenic disturbance. These data highlight the need to protect wetlands to mitigate the risk of avoidable contributions to climate change. Wetlands store large quantities of carbon, the distribution and quantity of which is little known. Here, Nahlik and Fennessy use data collected as part of the 2011 National Wetland Condition Assessment to estimate wetland carbon stocks across the United States, illustrating total storage of 11.52 PgC.

… estimates of their carbon storage potential. … of carbon stored globally in soils of salt marshes and mangrove swamps. We then examine spatial patterns in carbon density and storage …

Soil organic carbon (SOC) in coastal wetlands, also known as “blue C,” is an essential component of the global C cycles. To gain a detailed insight into blue C storage and controlling factors, we studied 142 sites across ca. 5000 km of coastal wetlands, covering temperate, subtropical, and tropical climates in China. The wetlands represented six vegetation types (Phragmites australis, mixed of P. australis and Suaeda, single Suaeda, Spartina alterniflora, mangrove [Kandelia obovata and Avicennia marina], tidal flat) and three vegetation types invaded by S. alterniflora (P. australis, K. obovata, A. marina). Our results revealed large spatial heterogeneity in SOC density of the top 1‐m ranging 40–200 Mg C ha−1, with higher values in mid‐latitude regions (25–30° N) compared with those in both low‐ (20°N) and high‐latitude (38–40°N) regions. Vegetation type influenced SOC density, with P. australis and S. alterniflora having the largest SOC density, followed by mangrove, mixed P. australis and Suaeda, single Suaeda and tidal flat. SOC density increased by 6.25 Mg ha−1 following S. alterniflora invasion into P. australis community but decreased by 28.56 and 8.17 Mg ha−1 following invasion into K. obovata and A. marina communities. Based on field measurements and published literature, we calculated a total inventory of 57 × 106 Mg C in the top 1‐m soil across China's coastal wetlands. Edaphic variables controlled SOC content, with soil chemical properties explaining the largest variance in SOC content. Climate did not control SOC content but had a strong interactive effect with edaphic variables. Plant biomass and quality traits were a minor contributor in regulating SOC content, highlighting the importance of quantity and quality of OC inputs and the balance between production and degradation within the coastal wetlands. These findings provide new insights into blue C stabilization mechanisms and sequestration capacity in coastal wetlands.

Impacts of land use, specifically soil disturbance, are linked to reductions of soil organic carbon (SOC) stocks. Correspondingly, ecosystem restoration is promoted to sequester SOC to mitigate anthropogenic greenhouse gas emissions, which are exacerbating global climate change. Restored wetlands have relatively high potential to sequester carbon compared to other ecosystems, but SOC accumulation rates are variable, which leads to high uncertainty in sequestration rates. To assess soil properties and carbon sequestration rates of freshwater mineral soil wetlands, we analyzed an extensive database of SOC concentrations from the Prairie Pothole Region (549 wetlands over 160,000 km2), which is considered one of the largest wetland ecosystems in North America. We demonstrate that SOC of wetland catchments varies among inner, transition, toe slope, and upland landscape positions (LSPs), as well as among land uses and soil depth segments. Soil organic carbon concentrations were greatest in the inner portion of the catchment (66 Mg ha-1) and progressively decrease towards the upland LSP (43 Mg ha-1). We also conducted a regional extrapolation based on LSP- and land-use-specific SOC stocks, and estimated that wetland and upland areas of PPR wetland catchments contain 141 and 178 Tg of SOC in the upper 15 cm of the soil profile, respectively. Regressing SOC by restoration age (years restored) showed that sequestration rates, which differ by LSP and depth, ranged from 0.35 to 1.10 Mg ha-1 year-1. Using these SOC sequestration rates, along with data from natural and cropland reference sites, we estimated that it takes 20 to 64 years for SOC levels of restored wetlands to return to natural reference conditions, depending on LSP and depth segment. Accounting for LSP reduces uncertainty and should refine future assessments of the greenhouse gas mitigation potential from wetland restoration.

… This Tier 2-oriented carbon stock assessment provides a scientific method that … carbon stock sizes and locations is needed for the first Tier 2 estimation of wetland soil organic carbon for …

This study was conducted to understand how different wetland vegetation-land use types influenced the storage and stability of soil organic carbon (SOC) in surface soils. We determined the concentration and chemical composition of SOC in both density (including light fraction organic carbon (LFOC) and heavy fraction organic carbon (HFOC)) and particle size fractions (including <2 μm, 2-63 μm, 63-200 μm and 200-2000 μm) in four wetland land use types covered with different vegetation: lake-sedge, reed, willow and poplar wetlands. Results showed that the concentrations and stock of SOC and LFOC in willow and poplar wetlands were significantly higher than those in lake-sedge and reed. However, a higher proportion of alkyl-C and a lower proportion of O-alkyl-C were observed in lake-sedge and reed wetlands than in willow and poplar, suggesting that accumulated C in willow and poplar wetlands was less stable than that in lake-sedge and reed. For all particle-size fractions except the silt (2-63 μm), the SOC concentrations were highest in willow and lowest in reed wetland surface soils, while their alkyl-C/O-alkyl-C (A/O-A) and hydrophobic-C/hydrophilic-C ratios progressively decreased from lake-sedge and reed wetland surface soils to poplar and willow surface soils. Moreover, the ratios of A/O-A and hydrophobic-C/hydrophilic-C in surface soils generally decreased with increasing concentrations of SOC in particle-size fractions, with these stability indexes being lowest in the largest particle-size fraction. These results indicate that the wetland vegetation-land use types that could incorporate more C into finer particle-size fractions had a greater potential for sequestering more stable C in such wetland ecosystems. Different wetland vegetation-land use types resulted in significant changes in the concentration and chemical structure of SOC, which could affect soil C sequestration and dynamics, C cycling in wetland ecosystems. Although both willow and poplar forests could increase SOC stock, the stability of SOC in willow wetland was higher. Therefore, on balance (stock and stability) the land use of wetland for willow forest could be a more promising way for enhancing soil C sequestration in wetlands.

… , changes in topography and elevation of silt-promoting wetlands and restoration wetlands … , which may affect wetland soil carbon sequestration capacity and even carbon storage. From …

Identifying the SOC levels and revealing the potential of SOC storage of ecosystems difficult to sample and study are necessary contributions to the understanding of the global reserves of SOC. Wetlands store large amounts of SOC within their soils. They have an important role in water regulation and have great biological and floristic diversity. Therefore, this study aimed to assess the SOC stock in Atillo micro-watershed in the Ecuadorian Andean wetlands at two soil depths (0–30 cm and 30–60 cm below ground) and to assess the importance of the ecosystem and its conservation in favor of reducing emissions due to degradation processes. For that, we sampled the study zone with 101 composite samples of soil to obtain the SOC storage for each sample point in Mg/ha. A SOC estimation to evaluate its spatial distribution was performed using the geostatistical method Kriging. The results show a high storage capacity of the study zone with SOC values of 126 to 454 Mg/ha in the 0–30 cm soil profile and 148 to 350 Mg/ha in the 30–60 cm soil profile. The preservation and protection mechanisms of high SOC reserves should be taken into account to prevent the emission of CO2.

… types and communities in more detail when assessing the role of wetlands as carbon sequestering systems … area and thus the organic matter inputs into the wetland soil. The increase …

… for carbon and sediment. We compared rates of carbon accretion and soil accretion across 20 wetlands … based on a rapid assessment method, which was verified by their floristic quality. …

… soil pH showed no correlation with SOC. Our results demonstrate that the carbon budget of inland wetlands … its economic value is closely related to characteristics of soil and vegetation. …

… storage, and (3) discuss the reasons for any spatial differences in soil annual C accumulation and soil C storage. … Wetland soil was brought back to the laboratory for natural air drying …

Wetlands are among the most important natural resources on earth. They provide a potential sink for atmospheric carbon but if not managed properly, they become a source of green house gases. However, only limited studies have been conducted to assess the roles and potentials of wetlands in carbon sequestration. Wetlands occupy approximately 5% of the total land area in Nepal, some of these being of international importance. However, there are major knowledge gaps in accurately quantifying carbon stored in them, as well as their carbon sequestration potential. Therefore, further research is needed to better understand the processes of carbon sequestration in wetland vegetation and soils. Key words: wetland, sink, carbon sequestration DOI: 10.3126/jowe.v2i1.1855 Journal of Wetlands Ecology , (2009) vol. 2, pp 41-45

… The peatland C balance will be discussed in more detail in the following section as peatland soils dominate wetland soil C storage. 5.2 Peatland Carbon Balance …

… and fluxes within natural and constructed freshwater wetlands, and specifically … assess the distribution and conversion of carbon in the water environment, particularly within wetland …

Highly productive coastal wetlands play an essential role in storing blue carbon as one of their ecosystem services, but they are increasingly jeopardized by intensive reclamation activities to facilitate rapid population growth and urbanization. Coastal reclamation causes the destruction and severe degradation of wetland ecosystems, which may affect their abilities to store blue carbon. To assist with international accords on blue carbon, we evaluated the dynamics of blue carbon storage in coastal wetlands under coastal reclamation in China. By integrating carbon density data collected from field measurement experiments and from the literature, an InVEST model, Carbon Storage and Sequestration was used to estimate carbon storage across the reclamation area between 1990 and 2015. The result is the first map capable of informing about blue carbon storage in coastal reclamation areas on a national scale. We found that more than 380,000 hectares of coastal wetlands were affected by reclamation, which resulted in the release of ca. 20.7 Tg of blue carbon. The carbon loss from natural wetlands to artificial wetlands accounted for 72.5% of total carbon loss, which highlights the major task in managing coastal sustainability. In addition, the top 20% of coastal wetlands in carbon storage loss covered 4.2% of the total reclamation area, which can be applied as critical information for coastal redline planning. We conclude that the release of blue carbon due to the conversion of natural wetlands exceeded the total carbon emission from energy consumption within the reclamation area. Implementing the Redline policy could guide the management of coastal areas resulting in greater resiliency regarding carbon emission and sustained ecosystem services.

… -term stra tegyfor wetland conservation. It has been difficult to estimate the net carbon sequestration potential of a wetland, because … Effective assessment of wetlands will only take …

… The deposits of carbon in wetland soils are large. There have been large losses of coastal … of the unit area C sequestration potential of coastal wetlands under current conditions before …

… pool with capacity of 770 GtC, overweighing the total carbon stor… Besides, the carbon sequestration rate of wetlands is … by the anaerobic characters of wetland soils as well as the lower …

Burial in sediments removes organic carbon (OC) from the short-term biosphere-atmosphere carbon (C) cycle, and therefore prevents greenhouse gas production in natural systems. Although OC burial in lakes and reservoirs is faster than in the ocean, the magnitude of inland water OC burial is not well constrained. Here we generate the first global-scale and regionally resolved estimate of modern OC burial in lakes and reservoirs, deriving from a comprehensive compilation of literature data. We coupled statistical models to inland water area inventories to estimate a yearly OC burial of 0.15 (range, 0.06–0.25) Pg C, of which ~40% is stored in reservoirs. Relatively higher OC burial rates are predicted for warm and dry regions. While we report lower burial than previously estimated, lake and reservoir OC burial corresponded to ~20% of their C emissions, making them an important C sink that is likely to increase with eutrophication and river damming. The magnitude of organic carbon burial in lakes and reservoirs is poorly constrained. Here, using a compilation of modern data from the literature and statistical modeling, the authors estimate a global yearly organic carbon burial of 0.15 Pg C in inland waters, of which 40% is stored in reservoirs.

… organic carbon (OC) burial rate and the total OC stock in the sediments of a tropical hydroelectric reservoir … OC stock accumulated in the sediments of a tropical reservoir by combining …

… of global sediment organic carbon burial in reservoirs and impoundments. … storage loss due to deposition of high bulk density sediments containing substantial amounts of organic matter…

… the Wujiangdu Reservoir (WJDR), a canyon reservoir located … with physicochemical data of sediment cores. The results … canyon reservoirs in the mainstream of the WJR, the storage …

… to (1) analyze the existing sediment distribution and OC storage in the sediment of the XAJR … of autochthonous and allochthonous organic matter (OM) in the sediment of the XAJR. In …

… some attention: burial of soil carbon in water catchment impoundments, lakes, … reservoirs," in order to avoid confusion between these water bodies and global stocks of carbon (reservoirs…

The lack of watershed-scale estimates of floodplain carbon stocks limits recognition of the important role of floodplains and river corridor restoration in efforts to enhance carbon sequestration. We use the South Platte River watershed of Colorado, USA as a case study to illustrate spatial patterns of, and controls on, floodplain carbon stocks at the watershed scale. This case study illustrates the disproportionate importance of floodplains for soil carbon stocks relative to adjacent uplands and provides an example of how spatially explicit data can be used to prioritize floodplain restoration with regard to carbon sequestration. We use the hydrogeomorphic floodplain tool GFPLAIN to delineate the extent of 100-year floodplains in the South Platte River watershed. We distinguish elevation bands for the steppe, montane, subalpine, and alpine zones. We also differentiate bead (floodplain width/channel width ≥ 5) and string (floodplain width/channel width < 5) reaches within the montane and subalpine zones. Drawing on prior, field-based measurements of organic carbon stock in downed, dead wood and soil in these floodplain types, we estimate total floodplain organic carbon stock based on median values of stock in different floodplain types and the spatial extent of these floodplain types. This estimate includes organic carbon stocks in lake and reservoir sediments in the watershed. Soil constitutes the greatest reservoir of floodplain carbon. The total estimated area of floodplain is 2916 km2, which is 4.3 % of the total watershed area of the South Platte River. Our preferred estimate is 42.7 Tg C stock (likely range of 39.1-42.7 Tg). This equates to 11.1 % of a previously estimated overall carbon stock (above and belowground biomass and soil organic carbon) in the entire watershed of 384 Tg C. Floodplains are thus disproportionately important, relative to their surface area, in storing organic carbon in this semiarid watershed. Field measurements of floodplain soil organic carbon stocks from across the globe indicate that this finding is not unique to this watershed, with implications for prioritizing floodplain management and restoration as a means of enhancing carbon sequestration.

… of organic carbon in sediments of the studied reservoirs … In the ZZ sediments, it ranged from 16.5 to 87.0 g C/kg dws (… The sediments of the not dredged part of the BI had the share …

Soil erosion and soil organic carbon (SOC) loss are not always linked linearly because SOC‐rich topsoil is eroded at the initial stages of degradation, while horizons with lower SOC content are eroded later, but often at higher rates. Small, silted‐up farm reservoirs potentially document this change during the period of sediment accumulation. This study tests the specific potential of small farm reservoir sediments from the South African Karoo to reconstruct 20th century SOC and total nitrogen (TN) change in rangeland soils. Five reservoir sediment profiles were sampled and texture, total organic carbon (TOC), TN and 137Cs of the samples were analyzed and compared. The results show that there clearly distinguishable flood couplets have been preserved in the sediment, illustrating their suitability for the chronological reconstruction of soil erosion and SOC. With one exception, the older sediments contain more TOC and TN than the younger ones. The TOC changed mostly in earlier than later stages of deposition, which is indicative of soil degradation early after the construction of the dams in the 1920s and 1930s. These distinct changes illustrate that the small reservoir sediments have the potential to reconstruct the impact of land‐use and associated soil erosion on SOC change in rangelands. Their analysis can therefore contribute to a better understanding of the land‐use associated changes of the global carbon cycle during the 20th century.

… critical zones for carbon transformation and storage, and lacustrine sediments sequestrate considerable amounts of organic carbon (OC). Understanding sedimentation processes and …

… organic carbon (SOC) in deep soil horizons and the processes influencing its turnover is critical for predicting the response of this large reservoir … of substantial SOC stocks to depths …

… in assessments of organic carbon (C) stock and the impacts of … and quality of carbon stored within the sediments of SFLs. … The sedimentary organic carbon content (TOC) ranged from …

The flow of organic matter (OM) along rivers and retention within floodplains contributes significantly to terrestrial carbon storage and ecosystem function. The storage and cycling of OM largely depend upon hydrogeomorphic characteristics of streams and valleys, including channel geometry and the connectivity of water across and within the floodplain. To examine the role of river morphology on carbon dynamics in mountain streams, we (a) quantify organic carbon (OC) storage in fine sediment, litter, and wood along 24 forested gravel‐bed stream reaches in the Rocky Mountains of CO, USA, (b) examine morphological factors that regulate sediment and OC storage (e.g., channel width, slope, logjams), and (c) utilize fluorescence spectroscopy to examine how the composition of fluorescent dissolved OM in surface water and floodplain fine sediment are influenced by channel morphology. Multivariate regression of the study reaches, which have varying degrees of confinement, slope, and elevation, indicates that OC storage per area is higher in less confined valleys, in lower gradient stream reaches, and at higher elevations. Within unconfined valleys, limited storage of fine sediment and greater microbial transformation of OM in multithread channel reaches decreases OC storage per area (252 ± 39 Mg C ha−1) relative to single‐thread channel reaches (346 ± 177 Mg C ha−1). Positive feedbacks between channel morphology and persistent channel‐spanning logjams that divert flow into multiple channels may limit the aggradation of floodplain fine sediment. Although multithread stream reaches are less effective OC reservoirs, they are hotspots for OM decomposition and provide critical resources to downstream food webs.

… In this paper, we (i) discuss the various reservoirs for OC storage in riparian … carbon retention and storage in riparian ecosystems, (iii) provide a synthesis of published OC storage in …

… the organic carbon fraction, because these boreal lakes store … amounts of inorganic C (2–4% of the total sediment carbon). … organic carbon burial efficiencies we observed in our lakes …

Lake eutrophication is a widespread challenge, and macrophyte reconstruction has been shown as an effective strategy for restoring shallow eutrophic lakes. However, the impacts of macrophyte on the sedimentary carbon sequestration and underlying mechanisms remain poorly understood. Here, we conducted a year-long field investigation to compare carbon dynamics in macrophyte-restored and unrestored areas within a typical urban lake, analyzing physicochemical properties, organic matter composition, and microbial community structure. Compared to the unrestored areas, macrophyte-restored areas showed ∼80% higher total sedimentary carbon, along with lower sediment pH and increased aromaticity (SUVA254) and humification (HIX) of both water-soluble and alkaline-extractable organic matter. In addition, sediments in the restored areas supported a higher microbial richness and a microbial community more enriched in Alphaproteobacteria. Partial least squares-path modeling revealed that enhanced carbon sequestration by macrophyte restoration was primarily driven by shifts in sedimentary organic matter composition. Reduction in labile substrates (e.g., peptides and protein-like components), coupled with lower sediment pH, shifted the microbial community toward taxa associated with enhanced carbon persistence (Alphaproteobacteria). Overall, our results demonstrate that macrophyte restoration enhances sediment carbon sequestration through initiating shifts in sedimentary organic matter composition that subsequently restructure organic matter-microbe-environment interactions. This study provides direct evidence that macrophyte restoration, as a nature-based solution widely applied in shallow eutrophic lakes, can contribute to carbon sequestration beyond its well-recognized role in water quality improvement.

… in sediments (Molot and Dillon 1997). Lake sediments are a considerable sink of organic carbon … A study in boreal Finland suggests that carbon sequestration at the landscape level is …

… Fuxian Lake, an oligotrophic lake, decreased by approximately 25 %. The greenhouse effect may further reduce the carbon sequestration capacity of lakes, particularly oligotrophic lakes…

… Organic carbon (OC) in lake sediments plays an important role in terrestrial ecosystem carbon … a number of shallow and freshwater lakes, with a total lake area of more than 8,000 km 2 , …

… assessment of the organic carbon burial in the lake sediments that accumulated over the past 100 years in the MLYB and (2) estimate the carbon storage of sediments in lakes (larger …

… Carbon stored in lake sediments then is recently fixed terrestrial carbon transferred into aquatic storage… Retained organic carbon was either stored in sediments or lost to the atmosphere …

… does not appear to depend strongly on lake size or other limnological parameters, allowing … all Alberta lake sediment to have the same organic matter content. Alberta lake sediments …

Abstract High mountain lakes are valuable sentinels of global change because they are sensitive to environmental stress and integrate changes in the atmosphere and their catchment areas. This study tested the hypothesis that local and regional anthropogenic stressors have affected productivity, sedimentation, and organic carbon burial in two such tropical high mountain lakes in central Mexico. We studied changes in the water column (Secchi disc depth, total suspended solids (TSS), and chlorophyll-a concentrations) and surface sediments (chlorophyll-a and organic carbon concentrations) in El Sol Lake and La Luna Lake during the period 2000–2018, and organic carbon burial rates in sediment cores (∼1884–2014) dated with lead-210 (210Pb). We quantified increasing water turbidity, TSS, and organic carbon in surface sediments in El Sol Lake. Different responses of the two lakes were caused by lower pH in La Luna Lake and a threefold residence time of TSS in El Sol Lake compared to La Luna Lake, mostly attributable to their different surface/volume ratios. Organic carbon burial rates were slightly higher at La Luna Lake until 2000, when they became higher at El Sol Lake due to increasing sediment accumulation and organic carbon concentrations. In both lakes, results show significantly higher organic carbon burial rates since the 1950s, likely resulting from the deposition of human-induced wind-blown particles derived from activities at the volcano slopes and long-distance transport from highly urbanized areas. Anthropogenic impacts rather than climate change, therefore, caused the recent higher organic carbon burial rates observed in both lakes. Methods and findings from this study provide a valuable basis for comparing changes in other high mountain lakes worldwide.

Recent studies have shown that sediments of temperate and tropical lakes are sinks for organic carbon (OC), but little is known about OC burial in subtropical lakes. There are questions regarding the ability of subtropical lakes to store OC, given their relatively warmwater temperatures, lack of ice cover, frequent water-column mixing, and labile carbon forms. We used 210Pb-dated sediment cores from 11 shallow Florida (USA) lakes to estimate OC burial, i.e. net OC storage, over the last ~100 years. Shallow Florida water bodies average ~30% OC content in their sediments and displayed rates of net OC accumulation (63–177 g C m-2 a-1) that are similar to natural temperate lakes, but lower than temperate agricultural impoundments. We considered the influence of lake morphometry on OC storage in our study lakes, but did not observe an inverse relationship between lake size and OC burial rate, as has been seen in some temperate lake districts. We did, however, find an inverse relation between mean water depth and OC sequestration. Despite recent cultural eutrophication and the associated shift from macrophyte to phytoplankton dominance in the Florida study lakes, overall OC burial rate increased relative to historic (pre-1950 AD) values. Lakes cover >9000 km2 of the Florida landscape, suggesting that OC burial in sediments amounts to as much as 1.6 Mt a-1. The high rate of OC burial in Florida lake sediments indicates that subtropical lakes are important for carbon sequestration and should be included in models of global carbon cycling.

… and organic carbon source. We find that the mineralization of organic carbon in lake sediments … The sequestration of organic carbon (OC) in the sediments of inland waters, both natural …

In the past few decades, many non-flooding uplands (NF) and permanent flooding waters (PF) have been turned into seasonal flooding wetlands (SF) at the global scale. This trend could severely threaten global climate system by changing carbon cycling in terrestrial and aquatic ecosystems. However, the effects of SF expansion on soil and sediment organic carbon (SOC) storage and carbon-nutrient stoichiometry are far from clearly understood. Therefore, we explored SOC storage and carbon-nutrient stoichiometry among adjacent NF, SF and PF using 817 samples at 0-100 cm depth increment at Poyang Lake and Shengjin Lake in the Yangtze River floodplain, China. The SFs of the two lakes were both Carex lakeshore wetlands. The NF of Shengjin Lake was a near-natural forest, while the NF of Poyang Lake was a disturbed grassland. The results showed that SOC storage at SFs of Poyang Lake and Shengjin Lake was 75.61 and 98.01 Mg C/ha at 0-100 cm depth increment. The difference in SOC storage among nearby NF, SF and PF was dependent on depth and disturbance. SOC storage at SF was equivalent to that at near-natural NF, but was much higher than that at disturbed NF. SOC storage at SF was 12.62%-24.50% higher than that at PF at 0-30 cm depth increment, but was 15.16%-25.87% lower than that at PF at 0-100 cm depth increment. Edaphic carbon and nutrients followed allometric relationships at most sites and C increased faster than N and P along the depth gradients. Carbon-nutrient stoichiometric relationships at SF and PF were similar, and were more coupled than those at near-natural NF. This research illustrates the strong effects of seasonal flooding on SOC sequestration in terrestrial and aquatic ecosystems, and expands our understanding of carbon cycling in these two ecosystems.

… Organic C burial in lakes and reservoirs occurs primarily through sedimentation of autochthonous organic matter … changes in storage capacity to calculate volumetric sedimentation rates …

… organic matter to lakes, as well as to a strong dependence of OC burial efficiency on oxygen exposure time. This study demonstrates that the carbon sink in lake sediments … sequestration…

… C (POC), and loss processes such as respiration within the water column and in sediments … organic matter preservation and which can vary by region and lake type are bulk sediment …

… Storage and stability of organic matter and fossil carbon in a Luvisol and Phaeozem with continuous maize cropping: A synthesis. Journal of Plant Nutrition and Soil Science 2008, 171 (…

Understanding the processes governing lateral terrestrial organic carbon transfer is confounded by the fact that organic carbon deposits on land have not yet been fully explored. Despite recent advances in understanding organic carbon deposition in aquatic ecosystems, the burial of organic carbon in dry depositional environments remains unclear. Here, combining large-scale field surveys and remote sensing techniques, we provide a robust estimate for sediment retention and organic carbon burial of check dams on the Chinese Loess Plateau. We find that the 50,226 active check dams have intercepted 10.2 ± 0.6 Pg eroded sediment during 1970-2020, which equals to 46% of the sediment load of Yellow River. Based on 86 deep sediment cores, we estimate that 21.6 ± 9.9 Tg of organic carbon was buried over the past 50 years by check dams with a burial rate of 468 ± 204 g C m−2 yr−1, approximately one order of magnitude higher than that of global lakes/reservoirs. We also find that the organic carbon burial efficiency of check dams (~80%) is significantly higher than in other depositional environments. We argue that organic carbon burial by check dams represents a significant terrestrial carbon sink and must be accounted for in global carbon budget. Check dams on the Chinese Loess Plateau are estimated to trap and bury approximately 10.2 ± 0.6 Pg of eroded sediment and 21.6 ± 9.9 Tg of organic carbon over the past 50 years, according to large-scale field surveys and remote sensing.

… sequestration structures. The average organic carbon content in sediment trapped by check dams … If estimated at this rate, the carbon storage in check dams of the Loess Plateau can …

… of check-dams on carbon sequestration, along with sediment … evaluated the carbon sequestration function of check-dams in … were approximately 11 000 check-dams distributed in the …

Soil erosion significantly influences the global carbon cycle by redistributing organic carbon (OC) from terrestrial to aquatic systems. Check dams, widely implemented for soil and water conservation, potentially influence carbon dynamics by trapping eroded sediments, but their role in carbon sequestration lacks quantitative assessment. This study combined large-scale survey sampling, radiocarbon analysis, and carbon budget equation in the Wuding River basin-a sub-basin of the Yellow River with the most severe soil erosion-to assess the impact of check dams on the basin-scale carbon cycle and clarify their mechanisms as carbon sinks. We found that check dams intercepted 3.7 Tg of OC during 1970-2020, reducing downstream OC export by 16.7%. More importantly, this sequestration suppressed the decomposition of OC during long-distance fluvial transport by 25.5%. The buried OC showed exceptional stability, with low OC content ranging from 1.95 to 2.35 g kg-1 and a high proportion of mineral-associated OC (81.7%). Radiocarbon dating revealed ancient ages, ranging from 2,350 to 10,860 years. Unique depositional conditions, such as rapid burial, a sand-clay layered structure, and anoxic environments, further inhibit the decomposition of OC. Notably, check dams not only mitigated soil erosion but also transformed erosion-prone areas into effective carbon sinks by reducing emissions and enhancing OC burial. These findings reconcile the soil carbon erosion paradox by demonstrating that soil and water conservation measures can significantly alter regional carbon budgets. Our results emphasize the dual role of check dams in soil conservation and climate mitigation, providing a scientific basis for optimizing their design and deployment to enhance terrestrial carbon sequestration.

BackgroundGlobal warming as a result of increased greenhouse gases (GHGs) concentration in the atmosphere is threating the existence of life on earth. Reducing the concentration of such gases with sequestering mechanism on the surface of the land helps to treat the problem. One of such methods is trapping carbon in the form of soil organic carbon (SOC) together with sediments, by implementing sediment trapping practices. Direct field measurements, calculations and laboratory analysis were used.ResultsThe result shows that sediment storage dams (SSDs) sequestered/trapped ~ 60.97*103 t of sediment with the SOC content ranged from 14 to 87 g kg− 1 and check dams (CDs) trapped 7.8*103 t of sediment with the SOC content ranged from 20 to 290 g kg− 1. In general, the studied SSDs and CDs sequestered ~ 44.68*105 kg of SOC together with ~ 68.8*106 kg of sediment. In this study, SSDs and CDs were found to be important SOC sequestering practices together with sediments.ConclusionsThus, it is concluded that soil and water conservation structures can be used as carbon sequestering methods to reduce the concentration of GHGs in the atmosphere in addition to reducing soil erosion.

… , carbon sequestration, which is caused by soil erosion and sedimentation resulting from check-dam … Overall, check dams act as significant carbon sinks. It is necessary to consider the …

Check dams are widely recognized as highly efficacious engineering interventions for preventing soil erosion, and they have been extensively promoted and employed worldwide. However, there is a dearth of comprehensive research on the carbon storage and carbon sequestration potential of check dams, impeding our understanding of carbon fate in sedimentary regions of terrestrial systems. The goal of this study is to evaluate the carbon storage and carbon sequestration potential of check dams within the Helong Region (HLR), utilizing measured data from subcatchments and collected key dam data. The results indicated that the horizontal distribution characteristics of organic carbon (OC) in the seven subcatchments within the Yanhe catchment exhibited a gradually increasing trend from upstream to downstream. The vertical distribution of OC content can be categorized into three patterns: initial decrease followed by fluctuation, initial decrease followed by fluctuating increase, and sudden increase followed by stability. The variation range of OC stored in the dam land was 1.47–598.21 Mg, and there existed a strong quadratic relationship between OC storage and the dam land area. The HLR encompasses a total of 3703 key dams, with a combined storage capacity of 39.89 × 108 m3 and controlling an area of 17951.6 km2. As of 2011, the sediment load and OC buried in key dams within the HLR were estimated to be 24.98 × 108 t and 6385.98 Gg, respectively. Assuming complete filling of all key dams, the estimated carbon sequestration potential of the key dams amounted to 6869.41 Gg. The research findings can provide a theoretical foundation for comprehending carbon redistribution and carbon sequestration in the erosion–deposition environment of terrestrial systems.

Soil organic carbon plays an important role in the global carbon cycle, accounting for 70% of the Earth's carbon. However, soil erosion can have a major impact on the stocks of soil carbon and other soil nutrients, such as nitrogen and phosphorous. Soil and water conservation techniques, such as the building of check dams, are usually employed to control sediment yields and the losses of other soil components. The aim of this research is thus to quantify the soil organic carbon (SOC), soil nitrogen (SN) and soil phosphorous (SP) retained by the check dams of a hydrologic and forest restoration project in the Sierra de Ávila mountain range (Ávila, Central Spain). Soil samples were taken from the sediment wedges of 30 check dams and from 30 native soils. Soil texture, electric conductivity, pH, C, N and P were measured in all the soil samples. The volume of sediment retained by the check dams was calculated by the Sections Method, which is very accurate in estimating the real volume of the sediment wedges. The total sediment yield in the area was thus estimated at 6.40 Mg·ha-1·yr-1 and the mean SOC, SN and SP densities were respectively 13.76, 0.48 and 0.05 kg·m-2. These findings thus are very reliable and allow us to conclude that check dams constitute an important instrument for controlling losses of SOC, SN and SP, and preventing these substances from passing into watercourses downstream of the area.

… However, the effects of these structures for carbon retention have … carbon retention effects of check dams in Yan’an prefecture of the Loess Plateau region of China based on check dam …

… sinks of soil carbon and nitrogen based on the combined performance of land use change and check-dam … for SOC and TSN in sediments trapped behind check-dams were lower than 1 …

Greenhouse gas reduction and carbon sequestration are crucial strategies for addressing climate change. However, extreme weather events such as heavy rainfall and typhoons trigger soil erosion and landslides that severely impact the environment. These events not only release substantial greenhouse gases into the atmosphere and water bodies through large-scale collapses but also significantly delay ecosystem recovery and carbon sequestration processes. As climate change intensifies, the potential benefits of soil and water conservation engineering in mitigating greenhouse gas emissions and enhancing carbon sinks have gained increasing attention. Check dams, as one of the key engineering structures for stabilizing sediment and preventing slope disasters, play a vital role in preventing large-scale landslides. While research on sediment stabilization mechanisms of check dams is well-established, studies on their organic carbon sequestration benefits remain limited. In particular, the temporal dynamics of carbon mechanisms are not well understood, making it difficult to provide solid scientific evidence for the carbon sequestration benefits of check dams.This study uses precipitation events as a baseline to investigate the effects of check dam engineering on soil carbon sequestration and explores the mechanisms of carbon flow and sequestration from watershed soil erosion to sediment deposition within check dams. The research methodology involves selecting watersheds with fragile geology susceptible to erosion for sample collection and analysis. By examining changes in sediment organic carbon content before and after precipitation events, we analyze the transformation and sequestration mechanisms of organic carbon during erosion and deposition processes. Furthermore, through precipitation event simulations, we quantify soil erosion rates in watersheds and assess carbon loss and retention during sediment deposition in check dams to establish a simple and feasible method for sampling and carbon sequestration calculation.The study aims to reveal the carbon sequestration benefits of check dams during sediment stabilization processes and, through baseline establishment, develop an economical and scientific method for estimating carbon sequestration capacity. This method can be applied to large-scale assessments of carbon sequestration benefits of check dam projects across different regions, providing new scientific perspectives and empirical evidence for the role of soil and water conservation engineering in climate change mitigation. This research not only helps deepen our understanding of the carbon sequestration benefits of check dams but also provides crucial references for policy formulation and engineering planning, further promoting the integration and implementation of climate change adaptation and mitigation strategies.Keywords: Check dam, Carbon sequestration, Watershed management, Soil erosion

… suggesting a new temporary carbon sink. We estimate that dam building in the Changjiang has sequestered ~4.9 ± 1.9 … building in river basins that deliver sediments to passive margins. …

… The soil carbon pool is the largest carbon pool in the land … the geological map of carbonate distribution, the soil samples … which result in the soil be gathered in a local depression. This …

… Despite growing recognition of soil organic carbon (SOC) as a … mapping in different landforms remains largely unquantified. This study systematically evaluated the accuracy of 12 soil …

… lower slope positions of depressions comprising 2% slope, … depression landforms enclosing 1–2% slope. Because of seasonal deposition of finer soil materials, they showed loamy soils …

… soil survey). Figure 5a exemplifies the methodology for a random sample which is situated in a depression landform… procedure for the mapping landforms on a soil-genesis and transport …

… and depressions) and a very heterogeneous soil cover. An … Terric Histosols (trHS) in depressions. This natural sequence is … landform classifiers (Fig.6) results in the conceptual soil …

… of hillslope ridges and convexities, along with infilling of shallow depressions within the original valley bottom. On convex-convex landforms had an average net erosion of − 0.32 ± 0.01 …

… location allowing for spillover of water from depressions. In areas with a low degree of … designated in the mapping unit name. Hence the discrimination offered at the higher alpha …

This study explores carbon sequestration in South Korea’s riverine wetlands, focusing on the four major rivers: Han, Yeongsan, Geum, and Nakdong. Field data from the Yeongsan River wetland, including 3D topography surveys, grainsize analyses, and loss-on-ignition measurements, were used to assess carbon stocks and their environmental drivers. The Yeongsan River was selected as a representative site due to its geomorphological, hydrological, and climatic similarities with the other three major rivers, which influence sediment transport and carbon dynamics. Carbon stocks of 3.31 megagrams (Mg) per hectare, observed in the Dam-Yang Stream Wetland, suggest that the four major rivers collectively have the potential to store approximately 23.42 million metric tons of carbon annually, accounting for 3.9% of South Korea’s carbon budget. Geomorphological features at different elevations significantly influence soil carbon storage, with finer sediments contributing to higher carbon retention in low-energy environments. Seasonal variations in stream geomorphology, driven by floods and tropical cyclones, are dominant factors regulating sediment transport and organic matter deposition. Our findings suggest that controlled discharge events could enhance sediment and organic material retention, boosting carbon sequestration across riverine wetlands. This study highlights the critical role of geomorphological and hydrological processes in enhancing wetland carbon storage and mitigating carbon emissions.

… exported carbon may be stored in floodplains. However, compared to sedimentary carbon … , corresponding to the lower mean Holocene soil erosion and floodplain accumulation rates. …

We examined soil properties and accumulation rates over the last ca. 100 years in four swamps and four marshes in southern Canada where these wetlands are common but under increasing anthropogenic pressure. One 50‐cm long core was collected from each wetland and analyzed to determine bulk density (BD) and organic matter (OM). Lead‐210 and cesium‐137 dating were used to estimate sediment accumulation rates. In the datable portion of each core, we determined the organic carbon (Corg), nitrogen (N), Corg/OM, Corg/N, Corg density, Corg stocks, and Corg accumulation rates. All parameters but one—Corg accumulation rates—were significantly different in swamps compared to marshes and between seasonally wet soils and those regularly flooded. Since 1950, Corg stocks varied from 6 to 13.6 kg m−2 with ≈23% more Corg in swamps than in marshes. When hydrology and deeper soils where considered, Corg stocks in regularly flooded wetlands were 60% higher than those of seasonally wet systems, emphasizing the role of hydrology in building up C stocks long‐term. Our measurements are within the wide range reported for similar systems in North America. The average rate of Corg accumulation in the studied wetlands (112 ± 87 g m−2 yr−1) is ≈50% higher than that of oligotrophic/ombrotrophic peatlands, but ≈47% lower than in tidal marshes from eastern Canada. Our study lends support to the case for wetland restoration through re‐wetting as an important nature‐based climate solution for mitigation of GHG emissions in areas where they were drained for agriculture and other purposes.

… rates of carbon accumulation in sediment ranged … sediment accumulation rates and pond perimeters and basin areas suggesting that peat may be a major source of sediment carbon. …

Abstract Delta wetlands are increasingly recognized as important sinks for ‘blue carbon,’ although this and other ecosystem services that deltas provide are threatened by human activities. We investigated factors that affect sediment accretion using short term (3 years using marker horizons) and longer-term measures (∼50 year using 137Cs soil core distribution and ∼100 year using 210Pb distribution), the associated carbon accumulation rates, and resulting changes in surface elevation in the Ebro River Delta, Catalonia, Spain. Fifteen sites were selected, representing the geomorphological settings and range of salinities typical of the delta's wetlands. Sediment accretion rates as measured by 137Cs distribution in soil cores ranged from 0.13 to 0.93 cm yr−1. Surface elevations increased at all sites, from 0.10 to 2.13 cm yr−1 with the greatest increases in natural impoundments with little connection to other surface waters. Carbon accumulation rates were highly spatially variable, ranging from 32 to 435 g C m−1 yr−1 with significantly higher rates at bay sites (p = 0.02) where hydrologic connectivity is high and sediment resuspension more intense. Sites with high connectivity had significantly higher rates of carbon accumulation (averaging 376 ± 50 g C m−1 yr−1) compared to sites with moderate or low connectivity. We also found high rates of carbon accumulation in brackish sites where connectivity was low and biomass production was characteristically higher than in saline sites. A stepwise regression model explained 81% of variability in carbon accumulation rates across all sites. Our data indicate deltaic wetlands can be important sinks for blue carbon, contributing to climate change mitigation.

… a sediment accumulation range of 7 to 70 × 10 6 t yr −1 . Applying a similar factor to … sediment accumulation rate, we obtained a range of 3 to 30 × 10 6 t yr −1 . Since our sedimentation …

Mangrove ecosystems are important coastal carbon sinks, with soil carbon storage strongly influenced by site‐specific hydrological, sedimentary, and climatic conditions. This study quantified soil carbon stocks in two mangrove systems in Puerto Rico—La Parguera and Laguna Grande—and evaluated the relative influence of hydrology, sediment deposition, and climate on carbon accumulation. Depth‐standardized soil carbon stocks (0–50 cm) were higher at Laguna Grande (166 ± 66 Mg C ha − 1 ) than at La Parguera (115 ± 68 Mg C ha − 1 ), with a marginal difference ( p  < 0.10). Differences between sites are consistent with contrasting hydrological regimes: La Parguera experiences greater tidal flushing, which may enhance organic matter export and decomposition, whereas Laguna Grande is a semi‐enclosed lagoon with restricted tidal exchange and higher standing biomass, conditions that may promote organic matter retention and carbon accumulation. Although regional climatic differences—higher temperatures and precipitation near Laguna Grande relative to La Parguera—may influence productivity and decomposition dynamics, hydrological setting and sediment retention appear to be primary controls on soil carbon storage. These findings emphasize the importance of incorporating hydrological processes and geomorphic context into blue carbon assessments and mangrove conservation strategies. Understanding how tidal exchange, sediment dynamics, and precipitation patterns interact is critical for predicting mangrove carbon responses to future climate change.

… PIC accumulation in the sediments of the YRD. Organic carbon is assumed to account for virtually all the carbon sequestered in wetland sediments, most accumulation rates lying in the …

Nontidal wetlands are estimated to contribute significantly to the soil carbon pool across the globe. However, our understanding of the occurrence and variability of carbon storage between wetland types and across regions represents a major impediment to the ability of nations to include wetlands in greenhouse gas inventories and carbon offset initiatives. We performed a large‐scale survey of nontidal wetland soil carbon stocks and accretion rates from the state of Victoria in south‐eastern Australia—a region spanning 237,000 km2 and containing >35,000 temperate, alpine, and semi‐arid wetlands. From an analysis of >1,600 samples across 103 wetlands, we found that alpine wetlands had the highest carbon stocks (290 ± 180 Mg Corg ha−1), while permanent open freshwater wetlands and saline wetlands had the lowest carbon stocks (110 ± 120 and 60 ± 50 Mg Corg ha−1, respectively). Permanent open freshwater sites sequestered on average three times more carbon per year over the last century than shallow freshwater marshes (2.50 ± 0.44 and 0.79 ± 0.45 Mg Corg ha−1 year−1, respectively). Using this data, we estimate that wetlands in Victoria have a soil carbon stock in the upper 1 m of 68 million tons of Corg, with an annual soil carbon sequestration rate of 3 million tons of CO2 eq. year−1—equivalent to the annual emissions of about 3% of the state's population. Since European settlement (~1834), drainage and loss of 260,530 ha of wetlands may have released between 20 and 75 million tons CO2 equivalents (based on 27%–90% of soil carbon converted to CO2). Overall, we show that despite substantial spatial variability within wetland types, some wetland types differ in their carbon stocks and sequestration rates. The duration of water inundation, plant community composition, and allochthonous carbon inputs likely play an important role in influencing variation in carbon storage.

… river were positively and sedimentation negatively correlated with OC stock. The dike … sediment quality (ie, OC concentration) for building up long-term soil OC stocks, whereas sediment …

River floodplains constitute an important element in the terrestrial sediment and organic carbon cycle and store variable amounts of carbon and sediment depending on a complex interplay of internal and external driving forces. Quantifying the storage in floodplains is crucial to understand their role in the sediment and carbon cascades. Unfortunately, quantitative data on floodplain storage are limited, especially at larger spatial scales. Rivers in the Scottish Highlands can provide a special case to study alluvial sediment and carbon dynamics because of the dominance of peatlands throughout the landscape, but the alluvial history of the region remains poorly understood. In this study, the floodplain sediment and soil organic carbon storage is quantified for the mountainous headwaters of the River Dee in eastern Scotland (663 km2), based on a coring dataset of 78 floodplain cross‐sections. Whereas the mineral sediment storage is dominated by wandering gravel‐bed river sections, most of the soil organic carbon storage can be found in anastomosing and meandering sections. The total storage for the Upper Dee catchment can be estimated at 5.2 Mt or 2306.5 Mg ha‐1 of mineral sediment and 0.7 Mt or 323.3 Mg C ha‐1 of soil organic carbon, which is in line with other studies on temperate river systems. Statistical analysis indicates that the storage is mostly related to the floodplain slope and the geomorphic floodplain type, which incorporates the characteristic stream power, channel morphology and the deposit type. Mapping of the geomorphic floodplain type using a simple classification scheme shows to be a powerful tool in studying the total storage and local variability of mineral sediment and soil organic carbon in floodplains. © 2019 John Wiley & Sons, Ltd.

Coastal wetlands provide key ecosystem services, including substantial long-term storage of atmospheric CO2 in soil organic carbon pools. This accumulation of soil organic matter is a vital component of elevation gain in coastal wetlands responding to sea-level rise. Anthropogenic activities that alter coastal wetland function through disruption of tidal exchange and wetland water levels are ubiquitous. This study assesses soil vertical accretion and organic carbon accretion across five coastal wetlands that experienced over a century of impounded hydrology, followed by restoration of tidal exchange 5 to 14 years prior to sampling. Nearby marshes that never experienced tidal impoundment served as controls with natural hydrology to assess the impact of impoundment and restoration. Dated soil cores indicate that elevation gain and carbon storage were suppressed 30-70 % during impoundment, accounting for the majority of elevation deficit between impacted and natural sites. Only one site had substantial subsidence, likely due to oxidation of soil organic matter. Vertical and carbon accretion gains were achieved at all restored sites, with carbon burial increasing from 96 ± 33 to 197 ± 64 g C m-2 y-1. The site with subsidence was able to accrete at double the rate (13 ± 5.6 mm y-1) of the natural complement, due predominantly to organic matter accumulation rather than mineral deposition, indicating these ecosystems are capable of large dynamic responses to restoration when conditions are optimized for vegetation growth. Hydrologic restoration enhanced elevation resilience and climate benefits of these coastal wetlands.

… fine sediments and allochthonous carbon that may accumulate from this source. Neither habitat nor dominant species were associated with differences among the nonriverine sites, but …

… attributes to variability in the belowground C stocks of saltmarshes in New South Wales (… over 140 sediment cores, we report mean C stocks in the surface metre of sediments (mean …

… showed that the average carbon accumulation rate in the sediments of coastal wetlands … rates of carbon accumulation among different vegetation types and sedimentation zones (…

… [7] We investigated carbon storage in 13 boreal lakes of the James Bay region in northern … .cgdi.gc.ca/) using the hydrological and topographical extensions in ArcMap GIS 9.3. software. …

Abstract Mangrove ecosystems store large amounts of 'Blue Carbon', in particular in the sediment. Research in the past decade has emphasized the quantitative significance of carbon storage in mangrove forests in climate change mitigation, mainly by determining carbon stocks and calculating potential CO2 emissions caused by mangrove degradation. However, while this approach focuses on the total amount of carbon that can be lost to degradation, it fails to capture the amount that is sequestered annually. Therefore, carbon accumulation in mangrove sediments also needs to be taken into account. This study (i) explains the differences between carbon stocks and carbon accumulation rates (CAR), (ii) it addresses the geographical variation of carbon storage and underlying factors and (iii) it assesses the global relevance of 'Blue Carbon' sequestration in mangrove sediments. Results indicate that reducing uncertainties in carbon storage estimates of individual systems requires a representative set of data that covers within-system variability. An example from Indonesia illustrates that a mangrove ecosystem with a high C stock can have a low CAR and vice versa. It is therefore conceivable that coastal environmental settings with high allochthonous supply of mineral sediment, organic matter and nutrients mostly have low carbon stocks, but high CARs. As these settings represent >80% of the global mangrove area they are most important in terms of long-term carbon storage. While a C stock is a measure of the "vulnerability potential" in the case of ecosystem degradation or total loss, a CAR is rather a measure of the "mitigation potential" of carbon storage in mangrove ecosystems. The global carbon storage in mangrove sediments of 32 Tg yr−1 estimated from CARs in this study is at the upper end of the range of global budgets (14.6–31.1 Tg yr−1, mean 22.9 Tg yr−1). It highlights that the mangrove carbon sink may be larger than previously thought, but the high variation in the global average CAR of 233 ± 280 g C m−2 yr−1 also indicates the need for further data.

Inland wetlands are critical carbon reservoirs storing 30% of global soil organic carbon (SOC) within 6% of the land surface. However, forested regions contain SOC-rich wetlands that are not included in current maps, which we refer to as ‘cryptic carbon’. Here, to demonstrate the magnitude and distribution of cryptic carbon, we measure and map SOC stocks as a function of a continuous, upland-to-wetland gradient across the Hoh River Watershed (HRW) in the Pacific Northwest of the U.S., comprising 68,145 ha. Total catchment SOC at 30 cm depth (5.0 TgC) is between estimates from global SOC maps (GSOC: 3.9 TgC; SoilGrids: 7.8 TgC). For wetland SOC, our 1 m stock estimates are substantially higher (Mean: 259 MgC ha^−1; Total: 1.7 TgC) compared to current wetland-specific SOC maps derived from a combination of U.S. national datasets (Mean: 184 MgC ha^−1; Total: 0.3 TgC). We show that total unmapped or cryptic carbon is 1.5 TgC and when added to current estimates, increases the estimated wetland SOC stock to 1.8 TgC or by 482%, which highlights the vast stores of SOC that are not mapped and contained in unprotected and vulnerable wetlands. A large proportion of wetland extent is not mapped in currently available national datasets. Incorporating newly revealed wetlands into soil carbon mapping methods increases estimates of wetland soil carbon stock by 482%.

Abstract. Soil carbon sequestration plays an essential role in mitigating atmospheric CO2 increases and the subsequently global greenhouse effect. The storages and dynamics of soil organic carbon (SOC) of 0–30 cm soil depth in different landscape types including beaches, reservoir and pond, reed wetland, forest wetland, bush wetland, farmland, building land, bare land (severe saline land) and salt field in the modern Yellow River Delta (YRD) were studied based on the data of the regional survey and laboratory analysis. The landscape types were classified by the interpretation of remote sensing images of 2000 and 2009, which were calibrated by field survey results. The results revealed an increase of 10.59 km2 in the modem YRD area from 2000 to 2009. The SOC density varied ranging from 0.73 kg m−2 to 4.25 kg m−2 at depth of 0–30 cm. There were approx. 3.559 × 106 t and 3.545 × 106 t SOC stored in the YRD in 2000 and 2009, respectively. The SOC storages changed greatly in beaches, bush wetland, farm land and salt field which were affected dominantly by anthropogenic activities. The area of the YRD increased greatly within 10 years, however, the small increase of SOC storage in the region was observed due to landscape changes, indicating that the modern YRD was a potential carbon sink and anthropogenic activity was a key factor for SOC change.

Tidal wetlands, widely considered the most extensive reservoir of soil organic carbon (SOC), can benefit from remote sensing studies enabling spatiotemporal estimation and mapping of SOC stock. We found that a majority of the remote-sensing-based SOC mapping efforts have been focused on upland ecosystems, not on tidal wetlands. We present a comprehensive review detailing the types of remote sensing models and methods used, standard input variables, results, and limitations for the handful of studies on tidal wetland SOC. Based on that synthesis, we pose several unexplored research questions and methods that are critical for moving tidal wetland SOC science forward. Among these, the applicability of machine learning and deep learning models for predicting surface SOC and the modeling requirements for SOC in subsurface soils (soils without a remote sensing signal, i.e., a soil depth greater than 5 cm) are the most important. We did not find any remote sensing study aimed at modeling subsurface SOC in tidal wetlands. Since tidal wetlands store a significant amount of SOC at greater depths, we hypothesized that surface SOC could be an important covariable along with other biophysical and climate variables for predicting subsurface SOC. Preliminary results using field data from tidal wetlands in the southeastern United States and machine learning model output from mangrove ecosystems in India revealed a strong nonlinear but significant relationship (r2 = 0.68 and 0.20, respectively, p < 2.2 × 10−16 for both) between surface and subsurface SOC at different depths. We investigated the applicability of the Soil Survey Geographic Database (SSURGO) for tidal wetlands by comparing the data with SOC data from the Smithsonian’s Coastal Blue Carbon Network collected during the same decade and found that the SSURGO data consistently over-reported SOC stock in tidal wetlands. We concluded that a novel machine learning framework that utilizes remote sensing data and derived products, the standard covariables reported in the limited literature, and more importantly, other new and potentially informative covariables specific to tidal wetlands such as tidal inundation frequency and height, vegetation species, and soil algal biomass could improve remote-sensing-based tidal wetland SOC studies.

… Soil is a major reservoir of terrestrial carbon (C), containing some 2500 Gt (1 Gt = 10 9 metric tons), of which soil organic carbon (OC) constitutes about 1550 Gt within the top 1 m of soil (…

… restoring degraded wetlands can enhance their carbon-sink … of soil organic carbon density (SOCD) in restored wetlands is … to map SOCD in a restored lake wetland and to assess its …

Soil samples were collected in raised-field wetlands of five typical functional zones (inlet zone, water reserve zone, outlet zone, aquaculture zone, industrial zone) in Baiyangdian Lake, China, from a depth of 0–30 cm. The soil organic carbon (SOC) content, density, and storage, and carbon pool index (CPI) were calculated for each typical zone, and spatial distribution of SOC storage in the region was estimated using the ordinary kriging, interpolated value method. Our results showed that the average values of SOC content and storage decreased with depth along the soil profiles. Lowest values of SOC content and storage were observed in the inlet zone, whereas the outlet zone showed the highest SOC content and the water reserve zone showed the highest SOC storage. Surface soils had higher heterogeneity with higher values of SOC content and storage than deeper soils. Storage of SOC was much lower in the south-east of the water reserve zone and the east of the inlet zone than in the north-west of the water reserve zone or in the east of the whole Baiyangdian Lake. Values of CPI followed the order water reserve zone &amp;gt; aquaculture zone &amp;gt; outlet zone &amp;gt; industrial zone &amp;gt; inlet zone. The SOC was positively correlated with water content and negatively correlated with soil bulk density (P &amp;lt; 0.01), but had no significant correlation with other soil properties.

… wetland databases, national inventory data and in situ measurement of soil organic carbon (… and validation of a global database of lakes, reservoirs and wetlands J. Hydrol. 296 1–22 …

… Soil organic carbon (SOC) and soil inorganic carbon (SIC) are key components of the global wetland soil carbon pool, which plays a crucial role in carbon cycling. However, research …

… age were important influential factors affecting SOC after wetland restoration, with the first 2 … that wetland restoration is inefficient in terms of SOC recovery and that wetland restoration to …