Biological processes dominate the dynamic changes in the dissolved inorganic carbon ion equilibrium system of coastal wetlands under tidal influence.

Response of dissolved inorganic carbon dynamics to simulated tidal hydrological processes in coastal wetlands

Sources and carbon sequestration mechanism of soil inorganic carbon in coastal wetland of Jiaozhou Bay, China

Optimization of nitrogen, water and salinity for maximizing soil organic carbon in coastal wetlands

Sea-level rise enhances carbon accumulation in United States tidal wetlands

Divergent response of blue carbon components to wetland types and hydrological effects in typical estuarine wetlands of Jiaozhou Bay, China

Litter of Suaeda glauca, Phragmites australis, and Spartina alterniflora from coastal wetland of Jiaozhou Bay was decomposed in a laboratory experiment. The contents of soil labile organic carbon including dissolved organic carbon (DOC) and microbial biomass carbon (MBC) were determined, with the spectra characteristics of which being investigated by three-dimensional fluorescence spectroscopy. The results showed that the contents of soil labile organic carbon during litter decomposition increased first, then decreased, and finally tended to be stable. Different litter types and adding ways had different effects on soil labile organic carbon. The contents of soil DOC and MBC decreased in the order of Suaeda glauca, Spartina alterniflora and Phragmites australis. Soil mixed with bulk leaf litter had more soil labile organic carbon than surface mulch. The number and position of fluorescence peak, and fluorescence intensity changed during litter decomposition. No tyrosine-like peaks appeared in the soil with litter addition. Many factors drove litter decomposition, with microbial decomposition being the dominant factor and litter nature as the essential factor. Litter decomposition could improve the content of soil active organic carbon and enhance the stability of soil carbon pool. Litter decomposition changed the structure and chemical composition of soil DOC, which improved its ability of migration and transformation in soil. Moreover, this process enhanced its biodegradability and microbial bioavailability, promoted the production of endogenous DOC by microorganisms, and consequently stimulated carbon cycling of wetland soil.

Effects of water and salinity regulation measures on soil carbon sequestration in coastal wetlands of the Yellow River Delta

PDF HTML阅读 XML下载 导出引用 引用提醒 三江平原不同湿地类型土壤活性有机碳组分及含量差异 DOI: 10.5846/stxb201405060894 作者: 作者单位: 中国科学院东北地理与农业生态研究所,河南南阳师范学院生命科学与技术学院,中国科学院东北地理与农业生态研究所,中国科学院东北地理与农业生态研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院战略性先导科技专项课题(XDA05050508);国家自然科学基金项目(31100320,41171047)联合资助 Compositions and contents of active organic carbon in different wetland soils in Sanjiang Plain, Northeast China Author: Affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences,Department of Life Science and Technology, Nanyang Normal University, Henan province,Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences,Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:土壤活性有机碳对土壤干扰的反应较快,是土壤有机碳早期变化的敏感性指标。近50年来,三江平原湿地土壤有机碳库受农事活动影响较大。为了探讨不同湿地类型土壤活性有机碳主要组分土壤可溶性有机碳(Dissolved organic carbon, DOC)、微生物量碳(Microbial biomass carbon, MBC)和易氧化有机碳(Easily oxidized organic carbon, EOC)的分布差异及主要影响因子,选择了三江平原洪河自然保护区4种典型的湿地类型(小叶章+沼柳湿地、小叶章湿地、毛苔草湿地和芦苇湿地)为研究对象。分析了不同湿地类型土壤可溶性有机碳,微生物量碳和易氧化有机碳在0-30 cm土层内的分布特征和分配比例及其与有机碳、土壤养分和酶活性指标(蔗糖酶、纤维素酶和过氧化氢酶)之间的相关关系。结果表明:(1) 4种湿地类型土壤DOC、MBC和EOC含量均随土层深度的增加而减少。不同湿地类型之间土壤活性有机碳含量在0-30 cm土层内存在显著性差异(P < 0.05),相对于长期淹水的毛苔草湿地和芦苇湿地而言,未淹水的小叶章+沼柳湿地和小叶章湿地具有较高的DOC,MBC和EOC含量。(2) 土壤DOC、MBC和EOC占有机碳比例分别为0.27%-0.63%,1.27%-5.94%和19.63%-41.25%。土壤DOC所占比例呈先增后减的变化趋势,最大的比例均出现在10-20 cm。MBC所占比例在土壤剖面上则未表现出一致的变化规律,而EOC所占比例则随土层深度的增加而逐渐减少。(3) 土壤DOC占SOC比例以小叶章湿地最高,MBC和EOC占SOC的比例则以小叶章+沼柳湿地最高。而长期淹水的毛苔草湿地和芦苇湿地则具有更低的DOC,MBC和EOC比例。(4) 综合分析表明,4种湿地类型土壤DOC, MBC 和EOC两两之间存在极显著相关性关系,它们除了与碳氮比相关性不显著外,与土壤有机碳,全氮,全磷养分和酶活性指标间相关性均达到极显著水平,尤其是与有机碳和全氮的相关性系数更高,此外DOC与纤维素酶,MBC与过氧化氢酶相关性更大。由此可见,土壤碳氮磷养分和酶活性是影响土壤活性有机碳组分分布的重要因素。 Abstract:Soil active organic carbon (AOC) fractions are good indicators of soil carbon stock change because of their rapid response to soil disturbances in natural ecosystems. Agricultural activities in the last 50 years have greatly influenced the soil organic carbon (SOC) of natural wetlands on Sanjiang Plain, China. The main objective of this study was to assess differences in the distribution of soil AOC fractions, including dissolved organic carbon (DOC), microbial biomass carbon (MBC), and easily oxidized organic carbon (EOC), and the main influencing factors in four different types of wetlands in the Honghe National Natural Reserve of Sanjiang Plain. The contents and allocation ratios of soil DOC, MBC, and EOC were investigated at three soil depths (0-10, 10-20, and 20-30 cm) in four types of wetlands: (1) a mixed Calamagrostis angustifolia and Salix brachypoda wetland (CSW), (2) a C. angustifolia wetland (CAW), (3) a Carex lasiocarpa wetland (CLW), and (4) a Phragmites australis wetland (PAW). The relationships among the three soil AOC fractions and soil nutrient contents (SOC, total nitrogen [TN], total phosphorus [TP]) and enzyme activity (sucrase, cellulase, and catalase) were also analyzed. The results showed that DOC, MBC, and EOC content gradually decreased with increasing soil depth in the 0-30 cm soil layer of all four wetlands. However, significant differences (P < 0.05) were noted for the soil AOC fractions among the four wetlands. The DOC, MBC, and EOC content was significantly higher in non-flooding CSW and CAW compared to long-term flooding CLW and PAW. In the four wetlands, the ratios of soil DOC, MBC, and EOC to SOC content at the three soil depths ranged from 0.27% to 0.63%, 1.27% to 5.94%, and 19.63% to 41.25%, respectively. In addition, the trend in the changes of soil DOC to SOC ratios initially increased, followed by a decrease along the soil profiles, with peak values being documented for the 10-20 cm soil layer. No specific trend was noted for MBC to SOC ratios, but EOC to SOC ratios decreased with soil depth. The highest DOC to SOC ratio was obtained for CAW, whereas the highest MBC and EOC to SOC ratios were obtained for CSW. In contrast, lower DOC, MBC, and EOC to SOC ratios were observed in the long-term flooding CLW and PAW. Furthermore, positive correlations were observed among DOC, MBC, and EOC in all four wetlands. Our results showed that DOC, MBC, and EOC content was strongly correlated with SOC, TN, and TP content as well as with the enzyme activity indicators in the four wetland soils, but no significant correlation was noted for the C/N ratio. A higher correlation coefficient was observed between these three AOC fractions with SOC and TN content. Furthermore, highly significant relationships were observed between DOC content and cellulase activity, as well as between MBC content and catalase activity. In conclusion, the soil AOC fractions were mainly influenced by soil nutrient content (SOC, TN, and TP) and enzyme activity, which are associated with the C cycle. 参考文献 相似文献 引证文献

Soil labile organic carbon and soil enzymes play important roles in the carbon cycle of coastal wetlands that have high organic carbon accumulation rates. Soils under three vegetations (Phragmites australis, Spartina alterniflora, and Scirpusm mariqueter) as well as bare mudflat in Hangzhou Bay wetland of China were collected seasonally. Seasonal dynamics and correlations of soil labile organic carbon fractions and soil enzyme activities were analyzed. The results showed that there were significant differences among vegetation types in the contents of soil organic carbon (SOC) and dissolved organic carbon (DOC), excepting for that of microbial biomass carbon (MBC). The P. australis soil was with the highest content of both SOC (7.86 g kg-1) and DOC (306 mg kg-1), while the S. mariqueter soil was with the lowest content of SOC (6.83 g kg-1), and the bare mudflat was with the lowest content of DOC (270 mg kg-1). Soil enzyme activities were significantly different among vegetation types except for urease. The P. australis had the highest annual average activity of alkaline phosphomonoesterase (21.4 mg kg-1 h-1), and the S. alterniflora had the highest annual average activities of β-glycosidase (4.10 mg kg-1 h-1) and invertase (9.81mg g-1 24h-1); however, the bare mudflat had the lowest activities of alkaline phosphomonoesterase (16.2 mg kg-1 h-1), β-glycosidase (2.87 mg kg-1 h-1), and invertase (8.02 mg g-1 24h-1). Analysis also showed that the soil labile organic carbon fractions and soil enzyme activities had distinct seasonal dynamics. In addition, the soil MBC content was significantly correlated with the activities of urease and β-glucosidase. The DOC content was significantly correlated with the activities of urease, alkaline phosphomonoesterase, and invertase. The results indicated that vegetation type is an important factor influencing the spatial-temporal variation of soil enzyme activities and labile organic carbon in coastal wetlands.

Coastal distribution and driving factors for blue carbon fractions in the surface soil of a warm-temperate salt marsh in China

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.

Coastal salt marsh ecosystems are among the most important blue carbon (C) sinks. However, due to disparate data sources, limited sample sizes, and inconsistent methodologies, large variations exist in blue C stock estimation. Furthermore, studies focus on soil organic carbon (SOC), with minimal attention given to soil inorganic carbon (SIC). We conducted an intensive field survey across 114 sites along approximately 5000 km of China's coastline, investigating all C stock sectors associated with Phragmites australis, Spartina alterniflora, Suaeda salsa, and mudflats to better explore the biogeographical patterns and drivers of SOC and SIC and to estimate regional and national C pools. The results revealed significant spatial heterogeneity in SOC and SIC densities in the top 100 cm of soil, ranging from 20.89 to 246.95 Mg ha-1 and 0 to 249.33 Mg ha-1, respectively. These densities varied as a function of wetland location, vegetation type, climatic zone, and soil depth. The SOC and SIC content were jointly dependent on soil properties, climatic factors, and vegetation types. Soil available silicon was the most important environmental variable controlling both SOC and SIC. Climatic factors and vegetation types mainly controlled SOC and SIC through their interaction with soil properties. Increased vegetation productivity increased the SOC pool but decreased the SIC pool. Therefore, vegetation restoration in coastal wetlands should target suitable areas, such as soil pH < 7 or without existing SIC. Based on field measurements and published data, we estimated that the total C pool in the top 100 cm of soil across China's coastal salt marshes to be 91.55 Tg C, comprising 56.67 Tg SOC and 34.88 Tg SIC. These updated estimates, based on direct field measurements, provide new insights into blue C storage mechanisms and are crucial for validating parameterization of global coastal wetland C models.

There is evidence of connections between soil organic carbon (SOC) and inorganic carbon (SIC) in dryland of north China. However, fractions of SOC and SIC and the relationship are not well understood in the Loess Plateau that undergoes profound erosion and redeposition. A study was conducted in low-elevation cropland of Loess Plateau across two distinctive basins: Linfen basin (LFB) with lower soil pH (< 8.4) and subject to erosion–redeposition, and Yuncheng basin (YCB) with higher soil pH (> 8.6) and under the influence of the Yellow River. Soil samples were collected from 30 sites over 100 cm. We determined SOC, SIC, dissolved organic carbon (DOC) and other properties. Above 100 cm, SOC stock is significantly higher in LFB (10.0 ± 2.6 kg C m−2) than in YCB (6.9 ± 1.5 kg C m−2), but SIC lower in LFB (14.0 ± 2.5 kg C m−2) than in YCB (17.0 ± 5.7 kg C m−2). We find a significantly negative correlation between SOC and SIC stocks in LFB, but no clear relationship in YCB. DOC:SOC ratio (an indicator for DOC desorption or SOC stability) is significantly higher below 40 cm in YCB (1.9%) than LFB (1.2%), indicating stronger DOC desorption in YCB that has stronger hydrological process due to the influence of the Yellow River. Overall, SOC has a negative correlation with SIC and soil pH, and DOC:SOC ratio has a significantly positive correlation with soil pH. Our analyses suggest that erosion/re-deposition of topsoil is partly responsible for the negative SIC-SOC relationship in LFB, and high soil pH and stronger hydrological processes are attributable to relatively lower levels of SOC in YCB. This study highlights that soil carbon fractions in the lowland of Loess Plateau are influenced by many drivers, which leads to complex relationships between major soil carbon pools.

Coastal wetlands are considered as important “blue carbon” sink, and mowing management induced by anthropogenic activities is anticipated to profoundly affect soil carbon stocks in coastal wetlands. However, the impacts of mowing management on soil organic carbon (SOC) and enzyme activities and the mechanisms responsible for associated changes in Phragmites australis wetland remain uncertain. We conducted a field mowing manipulation experiment [control (CK), mowing and returning straw in December (12MS), mowing and removing straw in December (12MR), mowing and returning straw in March (3MS), and mowing and removing straw in March (3MR)] in P. australis wetland of the Yellow River Delta and quantified their impacts on soil quality, SOC, SOC fractions, and enzyme activities. Results showed that mowing treatments led to overall increases in soil nutrients [total carbon (TC), total nitrogen (TN), total phosphorus (TP), NH4+, and NO3−] and decreases in soil C/N ratio. The effects of mowing treatments on soil nutrient content were pronounced on topsoil than deep soil, and the maximum value of TC, TN, and TP reached in the 12MR treatment. Compared with CK, the 12MS, 12MR, 3MS, and 3MR treatments at 0–10 cm depth significantly enhanced SOC content by 8.78%, 32.9%, 16.5%, and 30.1%, respectively, but only the 3MS treatment enhanced SOC by 16.5% at 10–20 cm depth. Mowing treatments increased dissolved organic carbon (DOC), microbial biomass carbon (MBC), particulate organic carbon (POC), and labile organic carbon (LOC) and the contents of DOC, MBC, POC, and LOC decreased with soil depth. Mowing treatments stimulated the activities of sucrase and urease in topsoil, but only the 3MR treatment improved alkaline phosphatase activity in topsoil. Path analysis indicated that mowing management dominantly modulates SOC by changing sucrase activity, alkaline phosphatase activity, TN, TP, NH4+, NO3−, DOC, and LOC in 0–10 cm depth. However, SOC was significantly controlled by sucrase activity, urease activity, TC, TN, TP, LOC, and POC in 10–20 cm depth. Collectively, our results indicate that the continuous mowing management is beneficial to enhance soil quality and carbon storage capacity of P. australis wetlands, which will contribute to enhance carbon sequestration and sink capacity of coastal wetlands.

Effects of Spartina alterniflora control on soil carbon and nitrogen in coastal wetlands