Impact of expected global warming on C mineralization in maritime Antarctic soils: results of laboratory experiments
| Autor: | Eduardo de Sá Mendonça, Rui Tarcísio Barbosa, Paulo Negrais Seabra, Efrain Lázaro Reis, Juliana Vanir de Souza Carvalho, Carlos Ernesto Gonçalves Reynaud Schaefer |
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| Rok vydání: | 2010 |
| Předmět: |
South Shetland Islands
chemistry.chemical_classification Total organic carbon Soil organic matter Q10 Humic substances Mineralogy Geology Soil classification Mineralization (soil science) Oceanography chemistry Environmental chemistry Soil water Organic matter Microbial biodegradation Soil organic matter fragility Ecology Evolution Behavior and Systematics |
| Zdroj: | LOCUS Repositório Institucional da UFV Universidade Federal de Viçosa (UFV) instacron:UFV |
| ISSN: | 1365-2079 0954-1020 |
| DOI: | 10.1017/s0954102010000258 |
| Popis: | This study concerned the fragility of maritime Antarctic soils under increasing temperature, using the C dynamics and structural characteristics of humic substances as indicators. Working with four representative soils from King George Island (Lithic Thiomorphic Cryosol (LTC1 and LTC2), Ornithogenic Cryosol (OG) and Gelic Organosol (ORG)) we evaluated the total organic C and nitrogen contents, the oxidizable C and humic substances. Soil samples were incubated to assess the amount of C potentially mineralizable at temperatures typical of an Antarctic summer (5–14°C). Humic acids showed a higher aliphatic character and a smaller number of condensed aromatic groups, which suggests that these molecules from Antarctic soils are generally less resistant to microbial degradation than humic acids molecules from other regions. Based on 13C NMR spectra of MAS and CP/MAS, samples of soil humic acids of mineral soils (LTC1 and LTC2) have a higher content of aliphatic C, and heteroatom C, with lower levels of carbonyl and aromatic C, when compared with organic matter-rich soils (OG and ORG). Increasing incubation temperature led to a higher rate of mineralizable C in all soils. A sequence of soil fragility was suggested - LTC1 and LTC2 > OG > ORG - which showed a correlation with the Q10 coefficient and the ratio of labile and recalcitrant C fractions of soil organic matter (R2 = 0.83). |
| Databáze: | OpenAIRE |
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