Evaluation of methods for quantifying organic carbon in mangrove soils from semi-arid region
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The objective of this work was to evaluate methods for the determination of soil organic carbon (SOC) in mangrove samples in order to improve economically feasible and precise analytical alternatives
Materials and methods
Total SOC was quantified through elemental analyzer (EA), considered as the standard method, and compared to (a) a chemical method, based on the oxidation of SOC by potassium dichromate under various conditions: wet and dry samples, with or without external heat source and variations in sulfuric acid concentrations (3.6, 6, 9, and 12 mol L−1); (b) spectral reflectance; and (c) thermogravimetry.
Results and discussion
Regarding the chemical analysis, the use of dried samples improved the accuracy; external heat sources led to higher interference, with a lower correlation to EA SOC; and the higher correlation with the EA was obtained between a 6 M concentration of sulfuric acid (r = 0.733). The spectral reflectance method showed a low correlation between the EA (−0.492 < r < 0.252) while thermogravimetry showed the largest (r = 0.905).
SOC determination through chemical methods using dry samples with a sulfuric acid concentration of 6 M shows the best accuracy. As for the use of the spectral reflectance method in mangrove soils, further studies are needed to investigate the influence of pre- and postprocessing techniques. Thermogravimetry is characterized as the most adequate alternative method for SOC measurement when EA are not available since a correction factor is used (f = 0.27) to convert the soil organic matter content to SOC.
KeywordsBlue carbon Coastal wetland areas Mangroves Soil organic matter Spectral reflectance Thermogravimetry Walkley-Black
The first author thanks Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and São Paulo Research Foundation (FAPESP), grant no. 2014/11778-5, for financial support. The present study was partially funded by the Conselleria de Innovación e Industrial Xunta de Galicia (Spain) (PGIDIT08MDS036000PR) and PROMETEO program from the Ecuador government. The authors also thank both anonymous reviewers for their insightful comments.
- Da Silva EV, De Souza MMA (2006) Principais formas de uso e ocupação dos manguezais do Estado do Ceará. Caderno de Cultura e Ciênc 1:12–20Google Scholar
- de Mendonça ES, da Matos ES (2005) Matéria orgânica do solo: métodos de análises. UFV, Viçosa, Minas GeraisGoogle Scholar
- Dodge Y (2008) The concise encyclopedia of statistics. SpringerGoogle Scholar
- Gee GW, Bauder JW (1986) Particle-size analysis. In: Klute A (ed) Methods of soil analysis: part 1—physical and mineralogical methods; American Society of Agronomy; pp 383–411Google Scholar
- Howard PJA, Howard DM (1990) Use of organic carbon and loss-on-ignition to estimate soil organic matter in different soil types and horizons. Biol Fertil Soils 9(4):306–310Google Scholar
- Howard J, Hoyt S, Isensee K, Telszewski M, Pidgeon E (2014) Coastal blue carbon: methods for assessing carbon stock and emission factors in mangroves, tidal salt marshes, and seagrasses. Conservation International, Intergovernmental Oceanographic Commission of UNESCO, International Union for Conservation of Nature, Arlington, VirginiaGoogle Scholar
- IPCC (2014) 2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: wetlands. Hiraishi T, Krug T, Tanabe K, Srivastava N, Baasansuren J, Fukuda M, Troxler TG (eds). IPCC, SwitzerlandGoogle Scholar
- Kathiresan K (2005) Distribution of mangroves. UNU-INWEH-UNESCOGoogle Scholar
- Maia LP, Lacerda LD, Monteiro LHU, Souze GM (2006) Atlas dos manguezais do Nordeste do Brasil. SEMACE, Fortaleza, Ceará, BrazilGoogle Scholar
- Nellemann C, Corcoran E, Duarte CM, Valdés L, De Young C, Fonseca L, Grimsditch G (2009) Blue carbon. A rapid Response Assessment. United Nation Environment Programme, GRID-ArendalGoogle Scholar
- Pansu M, Gautheyrou J (2006) Handbook of soil analysis: mineralogical, organic and inorganic methods. Springer, 2006Google Scholar
- Schulte EE, Hopkins BG (1996) Estimation of soil organic matter by weight loss-on-ignition. In: Madgoff F, Tabatai MA, Hanlon EA (eds) Soil organic matter: analysis and interpretation. Soil Science Society Special Publication, pp 21–31Google Scholar