scholarly journals Carbon and Nitrogen Contents Driven by Organic Matter Source within Pichavaram Wetland Sediments

2022 ◽  
Vol 10 (1) ◽  
pp. 53
Author(s):  
Sathy A. Naidu ◽  
Kandasamy Kathiresan ◽  
Jeffrey H. Simonson ◽  
Arny L. Blanchard ◽  
Christian J. Sanders ◽  
...  
Keyword(s):  
Organic Matter ◽  
Fine Particles ◽  
Relevant Information ◽  
Conservation Strategies ◽  
Nutrient Storage ◽  
Tidal Zone ◽  
Δ13c And Δ15n ◽  
Carbon And Nitrogen ◽  
Mangrove Root ◽  
Nitrogen Contents

Differences in grain size, total organic carbon (OC), total nitrogen (TN), OC/TN ratios, and stable isotope (δ13C and δ15N) were assessed in sediments from areas covered by mangrove and saltmarsh vegetation within Pichavaram estuary (Southeast India). The mean percentage contents of silt and clays (70 vs. 19%), OC (5.7 vs. 2.0%), and TN (0.39 vs. 0.14%) were consistently higher in the mangrove as compared to those observed in the saltmarsh tidal zone. These differences may obey the higher deposition and retention of fine particles in the presence of a mangrove root system that may facilitate the accumulation and preservation of organic matter within these sedimentary systems. Further, higher OC and TN contents were associated to higher terrestrial or mangrove-derived organic matter contribution with lighter δ13C signatures (−26.0‰) in both sedimentary tidal zones, whereas lower OC and TN contents were associated to heavier δ13C signatures. This study is in agreement with previous studies which indicate that the presence of wetland vegetation may increase the carbon and nutrient storage capacity within estuarine ecosystems, highly relevant information for the establishment of further conservation strategies for blue carbon ecosystems at global scales.

Soil organic carbon and nitrogen sequestration and turnover in aggregates under subtropical leucaena–grass pastures

Soil Research ◽  
2018 ◽  
Vol 56 (6) ◽  
pp. 632 ◽  
Author(s):  
Kathryn Conrad ◽  
Ram C. Dalal ◽  
Ryosuke Fujinuma ◽  
Neal W. Menzies
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Soil Mass ◽  
Δ13c And Δ15n ◽  
Organic C ◽  
Carbon And Nitrogen ◽  
Nitrogen Sequestration ◽  
C And N

Stabilisation and protection of soil organic carbon (SOC) in macroaggregates and microaggregates represents an important mechanism for the sequestration of SOC. Legume-based grass pastures have the potential to contribute to aggregate formation and stabilisation, thereby leading to SOC sequestration. However, there is limited research on the C and N dynamics of soil organic matter (SOM) fractions in deep-rooted legume leucaena (Leucaena leucocephala)–grass pastures. We assessed the potential of leucaena to sequester carbon (C) and nitrogen (N) in soil aggregates by estimating the origin, quantity and distribution in the soil profile. We utilised a chronosequence (0–40 years) of seasonally grazed leucaena stands (3–6 m rows), which were sampled to a depth of 0.3 m at 0.1-m intervals. The soil was wet-sieved for different aggregate sizes (large macroaggregates, >2000 µm; small macroaggregates, 250–2000 µm; microaggregates, 53–250 µm; and <53 µm), including occluded particulate organic matter (oPOM) within macroaggregates (>250 µm), and then analysed for organic C, N and δ13C and δ15N. Leucaena promoted aggregation, which increased with the age of the leucaena stands, and in particular the formation of large macroaggregates compared with grass in the upper 0.2 m. Macroaggregates contained a greater SOC stock than microaggregates, principally as a function of the soil mass distribution. The oPOM-C and -N concentrations were highest in macroaggregates at all depths. The acid nonhydrolysable C and N distribution (recalcitrant SOM) provided no clear distinction in stabilisation of SOM between pastures. Leucaena- and possibly other legume-based grass pastures have potential to sequester SOC through stabilisation and protection of oPOM within macroaggregates in soil.

scholarly journals Spatial and Seasonal Variations of Sedimentary Organic Matter in a Subtropical Bay: Implication for Human Interventions

2020 ◽  
Vol 17 (4) ◽  
pp. 1362 ◽  
Author(s):  
Xuan Lu ◽  
Fengxia Zhou ◽  
Fajin Chen ◽  
Qibin Lao ◽  
Qingmei Zhu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Surface Sediment ◽  
Seasonal Variations ◽  
Seasonal Changes ◽  
Nitrogen Isotope ◽  
Anthropogenic Influences ◽  
Stable Carbon ◽  
Δ13c And Δ15n ◽  
Carbon And Nitrogen ◽  
Induced Changes

Elemental (total organic carbon (TOC) and total nitrogen (TN)) and stable carbon and nitrogen isotope compositions (δ13C and δ15N, respectively) in the surface sediment of Zhanjiang Bay (ZJB) in spring and summer were measured to study the spatial and seasonal changes of organic matter (OM) and assess the human-induced and environment-induced changes in the area. The OM in the surface sediment of ZJB was a mixture of terrestrial and marine sources, and was dominated by marine OM (54.9% ± 15.2%). Compared to the central ZJB, the channel and coastal ZJB areas had higher δ13C and δ15N values, higher TOC and TN concentrations, and lower TOC/TN ratios, indicating higher primary productivity and higher percentages of marine OM in the latter two subregions. Mariculture activities, sewage inputs, and dredging were responsible for these phenomena. Clear seasonal variations in OM were observed in ZJB. The average proportions of terrestrial OM in summer increased by 10.2% in the ZJB channel and 26.0% in the coastal ZJB area compared with those in spring. Heavy rainfall brought a large amount of terrestrial OM into the channel and coastal ZJB areas, leading to the increase of the terrestrial OM fraction in these two subregions in summer. In summary, anthropogenic influences had a significant influence on the spatial and seasonal variations of sedimentary OM in ZJB.

Stable Carbon and Nitrogen Isotopes in the Tidal Flat Sediments of Northern Yellow Sea

2013 ◽  
Vol 316-317 ◽  
pp. 223-226
Author(s):  
Bao Zhan Liu ◽  
Yu Liu ◽  
Ying Li ◽  
Hai Xia Wang
Keyword(s):  
Organic Matter ◽  
Tidal Flat ◽  
Yellow Sea ◽  
Nitrogen Isotopes ◽  
Stable Carbon ◽  
Terrestrial Organic Matter ◽  
Δ13c And Δ15n ◽  
Carbon And Nitrogen Isotopes ◽  
Carbon And Nitrogen ◽  
Northern Yellow Sea

Stable carbon and nitrogen compositions (δ13C, δ15N) of sedimentary organic matter were determined in the tidal flat of northern Yellow sea. The results showed that stable carbon and nitrogen isotopes compositions of the sediment samples ranged from −24.669～−19.457‰ and 2.125～7.043‰, respectively. The highest value was in St.DLD, and the lowest was in St.Z. Similar δ13C values were observed in St.H (−21.996±0.651‰) and St.P (−22.021±0.187‰), and similar δ15N values were between St.DLJ (5.502±0.223‰) and St.P (5.310±0.294‰). The δ13C and δ15N values did not show any significant regularity. The δ13C and δ15N signatures showed some fluctuation, no obvious regularity. The major source of terrestrial organic matter was from the emissions of river and human pollutant.

Variability of Settling Particles Fluxes and Isotopic Composition (δ13C and δ15N) from Material Trapped in Coastal Reefs of Abrolhos Bank, Eastern Brazilian Shelf

2020 ◽  
Vol 43 (3) ◽  
Author(s):  
Saulo Spanó ◽  
André Luiz Belem ◽  
Maria Do Rosário Zucchi ◽  
Paulo De Oliveira Mafalda Junior ◽  
Alessandro Lopes Aguiar ◽  
...  
Keyword(s):  
Organic Matter ◽  
Isotopic Composition ◽  
Environmental Monitoring ◽  
Isotopic Ratio ◽  
Isotopic Ratios ◽  
Sediment Composition ◽  
Δ13c And Δ15n ◽  
Sediment Samples ◽  
Carbon And Nitrogen ◽  
Average Value

Elemental and isotopic ratios (C/N, δ13C, δ15N) of sediment samples captured by PVC traps in eight stations along the coastal reefs of the Abrolhos region, Brazil, were analyzed. The study area is characterized by the influence of continental sediments on biogenic sediments. The highest δ13C values were found in the Sebastião Gomes (second shallower station), with average values close to -15‰ in all sampling periods. The isotopic ratio of carbon and nitrogen indicates that the organic matter analyzed has marine origin, with signature features of oceanic regions. The highest C/N ratio average value of 8.29 occurred in Nova Viçosa (the southernmost station and one of the shallowest) during the spring, in other seasons the average value was close to 7 in all periods. Although the values of C/N indicate a significantly marine contribution, δ15N values suggest that N series recycling processes are frequent during the time that the material remained in the environment. The results will provide a baseline for future environmental monitoring and studies on changes in sediment composition in an important set of coastal coral reefs.

scholarly journals Acid digestion on river influenced shelf sediment organic matter: Carbon and nitrogen contents and isotopic ratios

2017 ◽  
Vol 32 (2) ◽  
pp. 86-92 ◽  
Author(s):  
Virgil Pasquier ◽  
Pierre Sansjofre ◽  
Oanez Lebeau ◽  
Celine Liorzou ◽  
Marina Rabineau
Keyword(s):  
Organic Matter ◽  
Sediment Organic Matter ◽  
Isotopic Ratios ◽  
Acid Digestion ◽  
Carbon And Nitrogen ◽  
Shelf Sediment ◽  
Nitrogen Contents

scholarly journals Intra-annual variability of carbon and nitrogen stable isotopes in suspended organic matter in waters of the western continental shelf of India

2011 ◽  
Vol 8 (2) ◽  
pp. 3923-3951
Author(s):  
M. V. Maya ◽  
S. G. Karapurkar ◽  
H. Naik ◽  
R. Roy ◽  
D. M. Shenoy ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Column ◽  
Phytoplankton Production ◽  
Monsoon Period ◽  
Δ13c And Δ15n ◽  
Carbon And Nitrogen ◽  
Annual Variability ◽  
Post Monsoon ◽  
Biological Variables ◽  
Sw Monsoon

Abstract. The δ13C and δ15N of water-column suspended particulate organic matter (SPOM), elemental carbon and nitrogen concentrations, and C/N ratios in SPOM, along with ancillary chemical and biological variables including phytoplankton pigment abundance, were determined every month, with the partial exception of the southwest (SW) monsoon period, from March 2007 to September 2008 at a fixed site located off Goa (central west coast of India). The results reveal significant shifts in isotopic signatures, especially δ15N, of SPOM before and after the onset of the SW monsoon. Very low δ15N values, reaching a minimum of −4.17‰, are found during the pre-monsoon period. Although the average δ15N values for the SW monsoon (6.55‰) and post-monsoon (6.19‰) are substantially higher, these values are lower than expected from a region that experiences intense water-column denitrification, as well as those reported previously from the open Arabian Sea. Our results provide the first direct evidence for the addition of substantial amounts of isotopically light nitrogen by the diazotrophs, especially Trichodesmium, in the region. The δ15N of SPOM is generally lower than the mean value (7.38‰) for surficial sediments in the region, presumably because of diagenetic enrichment. The results support the notion that sedimentary δ15N may not necessarily reflect denitrification intensity in the overlying waters due to diverse sources of nitrogen and variability of its isotopic composition. The observed intra-annual variability of δ13C of SPOM is small (seasonal averages: pre-monsoon: −21.40‰, SW monsoon: −20.41‰ and post-monsoon: −22.15‰). Phytoplankton production and probably species composition could drive the observed changes. Occasional shifts in δ13C toward more negative values are suggestive of terrestrial inputs, but by and large the SPOM in the region seems to be of marine origin with relatively low and constant C/N ratios (5.8–6.5) occurring throughout the study period.

scholarly journals EVALUACION DE LA CONTAMINACION EN LOS SEDIMENTOS DE LA BAHIA DE CIENFUEGOS, CUBA

2016 ◽  
Vol 21 ◽  
Author(s):  
Nora Ablanedo ◽  
Humberto González ◽  
Isabel Campos ◽  
Ibis Torres
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Surface Sediment ◽  
Industrial Waste ◽  
Anthropogenic Sources ◽  
Waste Waters ◽  
Sediment Samples ◽  
Carbon And Nitrogen ◽  
Pollution Levels ◽  
Nitrogen Contents

Surface sediment samples were taken during two sampling campaigns in Cienfuegos bay (Cuba). The composition of meiobenthic communities, heavy metals and organic matter (carbón and nitrogen) contents were determined in order to assess the influence of anthropogenic sources in the pollution levels of this system. The results show the terrigenous origin of the sediments from different zones of the bay, which are chacacterized for high organic contents, features of decomposition and unstableness, and low number of taxonomic meiobenthic groups. The lowest meiobenthic densities simultaneously with the highest lead contents, were detected in the proximities of discharge points of urban and/or industrial waste waters.

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