Oxygen availability and temperature as driving forces for decomposition of aquatic macrophytes

Autor(es)

Passerini, M. D. ^[1] ; Cunha-Santino, M. B. ^{[1, 2]} ; Bianchini, Jr., I. ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Programa Posgrad Ecol & Recursos Nat, Rodovia Washington Luiz, Km 235, Caixa Postal 676, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos, Dept Hidrobiol, Rodovia Washington Luiz, Km 235, Caixa Postal 676, BR-13565905 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Aquatic Botany; v. 130, p. 1-10, APR 2016.
• Citações Web of Science: 3

Resumo

The decomposition of organic matter constitutes a fundamental ecosystem process where microorganisms, affected by temperature and oxygen availability, play a fundamental role. The decomposition rates interfere in the global carbon cycle and therefore, in the potential feedback to climate change. We addressed the individual and combined effects of water temperature (15, 20, 25 and 30 degrees C) and oxygen availability (aerobic and anaerobic) on the decomposition of three aquatic macrophytes (Eichhornia azurea, Eleocharis sp. and Salvinia auriculata) in microcosms carried out for 120 days. A first-order kinetic model was adopted to describe the kinetics of the decomposition. The decomposition had a biphasic pattern of mass loss: labile/soluble fraction (approximate to 15.4; 10.6 and 10.7% for E. azurea, Eleocharis sp. and S. auriculata, respectively) and refractory (approximate to 84.2; 89.4 and 89.0% for E. azurea, Eleocharis sp. and S. auriculata, respectively). Based on the decomposition kinetics, the leaching process was faster than the degradation of refractory compounds. Comparing the effect of temperature and the availability of dissolved oxygen, the latter seems more relevant for the decomposition process of these plants. Oxygen availability accelerated the decomposition 1.25 times compared to anoxic conditions, while a temperature increase of 10 degrees C accelerated it by 1.35 times. However, it is important to consider that these environmental variables act synergistically in the regulation of decomposition and therefore all of them influence the decomposition rates. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 10/15728-1 - Avaliação do crescimento de macrófitas aquáticas frente a diferentes concentrações de cádmio, chumbo, níquel e zinco, e seu potencial como ferramenta para a redução da concentração de metais na água de efluentes
• Beneficiário: Irineu Bianchini Júnior
• Modalidade de apoio: Auxílio à Pesquisa - Regular