33 research outputs found
Spartina alterniflora invasion controls organic carbon stocks in coastal marsh and mangrove soils across tropics and subtropics
No full textThis is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Coastal wetlands are among the most productive ecosystems and store large amounts of organic carbon (C)—the so termed “blue carbon.” However, wetlands in the tropics and subtropics have been invaded by smooth cordgrass (Spartina alterniflora) affecting storage of blue C. To understand how S. alterniflora affects soil organic carbon (SOC) stocks, sources, stability, and their spatial distribution, we sampled soils along a 2500 km coastal transect encompassing tropical to subtropical climate zones. This included 216 samplings within three coastal wetland types: a marsh (Phragmites australis) and two mangroves (Kandelia candel and Avicennia marina). Using δ13C, C:nitrogen (N) ratios, and lignin biomarker composition, we traced changes in the sources, stability, and storage of SOC in response to S. alterniflora invasion. The contribution of S. alterniflora-derived C up to 40 cm accounts for 5.6%, 23%, and 12% in the P. australis, K. candel, and A. marina communities, respectively, with a corresponding change in SOC storage of +3.5, −14, and −3.9 t C ha−1. SOC storage did not follow the trend in aboveground biomass from the native to invasive species, or with vegetation types and invasion duration (7–15 years). SOC storage decreased with increasing mean annual precipitation (1000–1900 mm) and temperature (15.3–23.4℃). Edaphic variables in P. australis marshes remained stable after S. alterniflora invasion, and hence, their effects on SOC content were absent. In mangrove wetlands, however, electrical conductivity, total N and phosphorus, pH, and active silicon were the main factors controlling SOC stocks. Mangrove wetlands were most strongly impacted by S. alterniflora invasion and efforts are needed to focus on restoring native vegetation. By understanding the mechanisms and consequences of invasion by S. alterniflora, changes in blue C sequestration can be predicted to optimize storage can be developed.State's Key Project of Research and Development Plan of ChinaNational Natural Science Foundation of Chin
Patterns and determinants of plant-derived lignin phenols in coastal wetlands: implications for organic C accumulation
No full text1. As a major plant-derived soil organic carbon (SOC) component, lignin phenols are unique biomarkers that reflect biogeochemical characteristics under different vegetation compositions and climatic zones in coastal wetlands. However, the latitudinal patterns of plant-derived lignin phenols to SOC and their link with the stability and controlling mechanisms remain poorly understood.
2. A total of 156 soil samples from 39 sites along a 5000 km coastal transect, were taken to explore the effects of biological and environmental controls on the patterns of lignin phenols. Lignin phenols had contents ranging from 1.91 to 83.3 mg g−1 OC, and a positive correlation was detected in grass-dominated salt marsh, but a weakly negative correlation in mangrove. Positive correlations between SOC or lignin content and C/V or S/V (the cinnamyl- or syringyl-to-vanillyl) ratios were found, while overall negative correlations between SOC or lignin content and (Ad/Al)V or (Ad/Al)S (the acid-to-aldehyde of vanillyl or syringyl units) ratios were detected, respectively, which confirmed the validity of these lignin biomarker degradation parameters.
3. Our findings revealed that plant C inputs and monomer ratios directly influenced the capacity of lignin phenols in soils. Lignin content and stabilization was mainly controlled by soil properties (i.e., pH, EC, sand/clay). Mean annual temperature (MAT) influenced the patterns of lignin phenols both directly by increasing decomposition and indirectly by changing the vegetation and soil biogeochemistry (i.e., microbial substrate availability).
4. Coastal wetlands are characterized by high primary productivity and C burial rate, yet plant-derived lignin phenols are not as much as we thought compared to microbial residues C. Precise identification and quantification of the origin, decomposition, and determinants of lignin phenols help us understand their contribution to C sequestration and its response to climate and environmental changes.Please see the README document ("Lignin_content_and_monomer_composition.csv", "Site_location.csv", "Soil_organic_carbon_content.csv", "Soil_properties.csv", "Vegetation_and_climate.csv") and the accompanying published article: Shaopan Xia, Zhaoliang Song, Weiqi Wang, Yaran Fan, Laodong Guo, Lukas Van Zwieten, Iain P. Hartley, Yin Fang, Yidong Wang, Zhenqing Zhang, Cong-Qiang Liu, and Hailong Wang. 2023. Patterns and determinants of plant-derived lignin phenols in coastal wetlands: implications for organic C accumulation. Functional Ecology. Accepted. DOI: 10.5061/dryad.j3tx95xk8
Funding provided by: Natural Science Foundation of Jiangsu ProvinceCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100004608Award Number: BK20221028Funding provided by: National Natural Science Foundation of ChinaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001809Award Number: 42141014Funding provided by: National Natural Science Foundation of ChinaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001809Award Number: 41930862Funding provided by: National Natural Science Foundation of ChinaCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001809Award Number: 42225101Please see the README document ("Lignin_content_and_monomer_composition.csv", "Site_location.csv", "Soil_organic_carbon_content.csv", "Soil_properties.csv", "Vegetation_and_climate.csv") and the accompanying published article: Shaopan Xia, Zhaoliang Song, Weiqi Wang, Yaran Fan, Laodong Guo, Lukas Van Zwieten, Iain P. Hartley, Yin Fang, Yidong Wang, Zhenqing Zhang, Cong-Qiang Liu, and Hailong Wang. 2023. Patterns and determinants of plant-derived lignin phenols in coastal wetlands: implications for organic C accumulation. Functional Ecology. Accepted. DOI: 10.5061/dryad.j3tx95xk
Organic matter composition and stability in estuarine wetlands depending on soil salinity
No full texthttp://dx.doi.org/10.13039/501100001809 National Natural Science Foundation of Chin
Microbial Necromass, Lignin, and Glycoproteins for Determining and Optimizing Blue Carbon Formation
No full textDistribution, Storage, and Factors Influencing Particulate and Mineral‐Associated Organic Matter in Paddy Soils
No full textAbstract Soil organic matter (SOM) reserves in paddies are approximately two times larger than those in upland soils, and therefore, rice paddies have a strong impact on terrestrial carbon (C) sequestration. Functional partitioning of SOM into particulate organic matter (POM) and mineral‐associated organic matter (MAOM) facilitates our understanding of C sequestration capacity in paddy soils. We analyzed POM and MAOM contents in 104 samples of topsoil and 81 samples of subsoil collected from paddies, and investigated how climate, nitrogen (N) fertilization, and soil depth regulate POM and MAOM storage. MAOM was the predominant fraction (45.3%–63.7%) of SOM in all paddy soils. As the SOC content increased, POM increased linearly, while the increase rate of MAOM slowed down, indicating a tendency for MAOM to reach saturation. The influence of mineral types on POM and MAOM protection exhibited depth‐dependent patterns: clay minerals showed stronger associations in topsoil, whereas amorphous iron oxides displayed increasing importance in subsoil. Climatic factors, particularly mean annual temperature (MAT), had contrasting effects on POM and MAOM storage: increasing MAT reduced MAOM content and stability while having a minor impact on POM. Increasing the N application rate had minimal impact on POM and MAOM storage due to crop harvest and the balance between microbial activity and mineral protection mediated by soil acidification. These findings are valuable for facilitating the sequestration and increasing the stability of SOM in paddies, providing information for global soil carbon storage strategies.Key Points Clay minerals play a stronger role in topsoil POM and MAOM storage, while amorphous iron becomes more influential in the subsoil A higher mean annual temperature reduces MAOM content and stability but has minimal effect on POM Increased nitrogen application minimally affects POM and MAOM storageAbstract Soil organic matter (SOM) reserves in paddies are approximately two times larger than those in upland soils, and therefore, rice paddies have a strong impact on terrestrial carbon (C) sequestration. Functional partitioning of SOM into particulate organic matter (POM) and mineral‐associated organic matter (MAOM) facilitates our understanding of C sequestration capacity in paddy soils. We analyzed POM and MAOM contents in 104 samples of topsoil and 81 samples of subsoil collected from paddies, and investigated how climate, nitrogen (N) fertilization, and soil depth regulate POM and MAOM storage. MAOM was the predominant fraction (45.3%–63.7%) of SOM in all paddy soils. As the SOC content increased, POM increased linearly, while the increase rate of MAOM slowed down, indicating a tendency for MAOM to reach saturation. The influence of mineral types on POM and MAOM protection exhibited depth‐dependent patterns: clay minerals showed stronger associations in topsoil, whereas amorphous iron oxides displayed increasing importance in subsoil. Climatic factors, particularly mean annual temperature (MAT), had contrasting effects on POM and MAOM storage: increasing MAT reduced MAOM content and stability while having a minor impact on POM. Increasing the N application rate had minimal impact on POM and MAOM storage due to crop harvest and the balance between microbial activity and mineral protection mediated by soil acidification. These findings are valuable for facilitating the sequestration and increasing the stability of SOM in paddies, providing information for global soil carbon storage strategies.Key Points Clay minerals play a stronger role in topsoil POM and MAOM storage, while amorphous iron becomes more influential in the subsoil A higher mean annual temperature reduces MAOM content and stability but has minimal effect on POM Increased nitrogen application minimally affects POM and MAOM storageNational Natural Science Foundation of China https://doi.org/10.13039/50110000180
Remobilization of Phosphorus from Sediments of Taihu Lake during Periods of Simulated Resuspension
No full textAn investigation into the effects of silver nanoparticles on natural microbial communities in two freshwater sediments
No full textThe expanding production and usage of commercial silver nanoparticles (AgNPs) will inevitably increase their environmental release, with sediments as a substantial sink. However, little knowledge is available about the potential impacts of AgNPs on freshwater sediment microbial communities, as well as the interactions between microbial communities and biogeochemical factors in AgNPs polluted sediment. To address these issues, two different sediments: a eutrophic freshwater sediment and an oligotrophic freshwater sediment, were exposed to 1 mg/g of either AgNO3, uncoated AgNPs (35-nm and 75-nm), or polyvinylpyrrolidone coated AgNPs (PVP-AgNPs) (30-50 nm) for 45 days. High-throughput sequencing of 16S ribosomal ribonucleic acid (16S rRNA) genes using the Illumina MiSeq platform was conducted to evaluate the effects of Ag addition on bacterial community composition. Moreover, sediment microbial biomass and activity were assessed by counting cultivable bacterial number and determining enzyme activities. During the 45-day exposure, compared with no amendment control, some treatments had resulted in significant changes and alterations of sediment biomass or bacterial enzyme activities shortly. While the microbial components at phylum level were rarely affected by AgNPs addition, and as confirmed by the statistical analysis with two-factor analysis of similarities (ANOSIM), there were no significant differences on bacterial community structure across the amended treatments. Redundancy analysis further demonstrated that chemical parameters acid-volatile sulfide (AVS) and simultaneously extracted silver (SE-Ag) in sediment significantly structured the overall bacterial community in sediments spiked with various silver species. In summary, these findings suggested that the ecotoxicity of AgNPs may be attenuated by the transformation under complex environmental conditions and the self-adaption of sediment microbial communities. (C) 2016 Elsevier Ltd. All rights reserved
An investigation into the effects of silver nanoparticles on natural microbial communities in two freshwater sediments
No full textThe expanding production and usage of commercial silver nanoparticles (AgNPs) will inevitably increase their environmental release, with sediments as a substantial sink. However, little knowledge is available about the potential impacts of AgNPs on freshwater sediment microbial communities, as well as the interactions between microbial communities and biogeochemical factors in AgNPs polluted sediment. To address these issues, two different sediments: a eutrophic freshwater sediment and an oligotrophic freshwater sediment, were exposed to 1 mg/g of either AgNO3, uncoated AgNPs (35-nm and 75-nm), or polyvinylpyrrolidone coated AgNPs (PVP-AgNPs) (30-50 nm) for 45 days. High-throughput sequencing of 16S ribosomal ribonucleic acid (16S rRNA) genes using the Illumina MiSeq platform was conducted to evaluate the effects of Ag addition on bacterial community composition. Moreover, sediment microbial biomass and activity were assessed by counting cultivable bacterial number and determining enzyme activities. During the 45-day exposure, compared with no amendment control, some treatments had resulted in significant changes and alterations of sediment biomass or bacterial enzyme activities shortly. While the microbial components at phylum level were rarely affected by AgNPs addition, and as confirmed by the statistical analysis with two-factor analysis of similarities (ANOSIM), there were no significant differences on bacterial community structure across the amended treatments. Redundancy analysis further demonstrated that chemical parameters acid-volatile sulfide (AVS) and simultaneously extracted silver (SE-Ag) in sediment significantly structured the overall bacterial community in sediments spiked with various silver species. In summary, these findings suggested that the ecotoxicity of AgNPs may be attenuated by the transformation under complex environmental conditions and the self-adaption of sediment microbial communities. (C) 2016 Elsevier Ltd. All rights reserved
Silicon accumulation controls carbon cycle in wetlands through modifying nutrients stoichiometry and lignin synthesis of <em>Phragmites australis</em>
No full textSilicon (Si) is one of the most abundant elements in the Earth’s crust but its role in governing the biogeochemicalcycling of other elements remains poor understood. There is a paucity of information on the role of Si in wetlandplants, and how this may alter wetland C production and storage. Therefore, this study investigated Si distribution,nutrient stoichiometry and lignin abundance in Phragmites australis from a wetland system in China tobetter understand the biogeochemical cycling and C storage. Our data show that Si content (ranging between0.202% to 6.614%) of Phragmites australis is negatively correlated with C concentration (38.150%–47.220%).Furthermore, Si content was negatively antagonistically related to the concentration of lignin-derived phenols inthe stem (66.763–120.670 mg g-1 C) and sheath (65.400–114.118 mg g-1 C), but only a weak relationship wasobserved in the leaf tissue (36.439–55.905 mg g-1 C), which is relevant to the photosynthesis or stabilizationfunction of the plant tissues. These results support the notion that biogenic Si (BSi) can substitute lignin as astructural component, due to their similar eco-physiological functions, reduces costs associated with ligninbiosynthesis. The accumulation of BSi increased total biomass C storage and nutrient accumulation due togreater productivity of Phragmites australis. On the other hand, BSi regulated litter composition and quality (e.g.,nutrient stoichiometry and lignin) that provide a possibility for the factors affecting litter decomposition. Thuscompeting processes (i.e., biomass quantity vs quality) can be influenced by Si cycling in wetlands.</p
