Pyrolysis‐Gas Chromatography/Mass Spectrometry of Soil Organic Matter Extracted from a Brazilian Mangrove and Spanish Salt Marshes

Abstract

The soil organic matter (SOM) extracted under different vegetation types from a Brazilian mangrove (Pai Matos Island, São Paulo State) and from three Spanish salt marshes (Betanzos Ría and Corrubedo Natural Parks, Galícia, and the Albufera Natural Park, Valencia) was investigated by pyrolysis‐gas chromatography/mass spectrometry (Py‐GC/MS). The chemical variation was larger in SOM from the Spanish marshes than in the SOM of the Brazilian mangroves, possibly because the marshes included sites with both tidal and nontidal variation, whereas the mangrove forest underwent just tidal variation. Thus, plant‐derived organic matter was better preserved under permanently anoxic environments. Moreover, given the low number of studied profiles and sedimentary–vegetation sequences in both areas, depth trends remain unclear. The chemical data also allow distinction between the contributions of woody and nonwoody vegetation inputs. Soil organic matter decomposition was found to cause: (i) a decrease in lignin contents and a relative increase in aliphatics; (ii) an increase in short‐chain aliphatics at the expense of longer ones; (iii) a loss of odd‐over‐even dominance in alkanes and alkenes; and (iv) an increase in microbial products, including proteins, sterols, short‐chain fatty acids, and alkanes. Pyrolysis‐gas chromatography/mass spectrometry is a useful tool to study the behavior and composition of SOM in wetland environments such as mangroves and salt marshes. Additional profiles need to be studied for each vegetation type, however, to improve the interpretability of the chemical data.

Biomarkers as indicators of sedimentary organic matter sources and early diagenetic transformation of pentacyclic triterpenoids in a tropical mangrove ecosystem

“…The methoxyphenols composition recorded in this study is consistent with previous reports from soil organic matter extracted under different vegetation types from a Brazilian mangrove (Pai Matos Island, São Paulo State) using Py-GC/MS techniques (Ferreira et al, 2009). Studies using alkaline CuO oxidation method for the molecular characterization of lignin-derived phenols from sediment of a North Brazilian mangrove ecosystem, indicated that Rhizophora mangle leaves are characterised by high cinnamyl phenol and low content in vanillic units (Dittmar and Lara, 2001).…”

“…Few studies have used successfully Py-GC-MS technique to relate the biogeochemical signature of mangrove sediments (e.g. Ferreira et al, 2009;Kumar et al, 2018).…”

Delineating the Role of Calcium in the Large‐Scale Distribution of Metal‐Bound Organic Carbon in Soils

“…The wetland sites of Experiment 1 had higher effective moisture than the upland sites (p < 0.05; Figure 2a). The topsoil had marginally lower pH (p = 0.1; Figure 2b) and higher SOC, N, WEOC concentrations and SOC:N ratios in the wetlands than uplands (p < 0.05; Figures 2c, 2d, S3a, and S3b), with the latter reflecting better preservation of plant-derived organic matter (Ferreira et al, 2009) Contrary to our hypothesis, although the absolute concentration of OC CBD was higher in the wetland (23.2 ± 4.1 mg g −1 soil) than upland topsoil (5.3 ± 1.0 mg g −1 soil; p < 0.05; Figure 2h), OC CBD % was comparable (16.1 ± 1.4% and 17.0 ± 1.9%, respectively; p > 0.05; Figure 2i). Nonetheless, this result suggests that in contrast to the common assumption, OC CBD contributes an equally important proportion of SOC in wetlands as in uplands.…”

Soil organic matter chemistry changes upon secondary succession in Imperata Grasslands, Indonesia: A pyrolysis–GC/MS study

“…Whereas of the fatty acids, the C 16 member clearly dominates in litters (up to 1.1%), in soils the C 12 member may reach almost the same abundance. The C 14 , C 16, and C 18 fatty acids can be both plant-derived and microbial, while the C 12 member is usually attributed to microbes (Perobelli Ferreira et al, 2009). Lignin compounds are especially abundant in litters.…”

“…Pyrolysis-GC/MS provides a large amount of structural information on SOM (De la Rosa et al, 2008;Hatcher et al, 2001;Parsi et al, 2007;Saiz-Jimenez and De Leeuw, 1986), and better identification and comparison of the SOM produced under different environments (Lienweber and Schulten, 1999;Nierop et al, 2001b;Perobelli Ferreira et al, 2009;Saiz-Jimenez et al, 1996). It also provides information on, e.g., selective decomposition and preservation of plant-derived material, admixture of microbial products, and addition of charred material (Buurman and Roscoe, 2011;Buurman et al, 2007b;Kaal et al, 2008).…”