Lipoxygenase-induced autoxidative degradation of terrestrial particulate organic matter in estuaries: A widespread process enhanced at high and low latitude

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Galeron, Marie-Aimee ^[1] ; Radakovitch, Olivier ^{[2, 3]} ; Charriere, Bruno ^[4] ; Vaultier, Frederic ^[1] ; Volkman, John K. ^[5] ; Bianchi, Thomas S. ^[6] ; Ward, Nicolas D. ^[7] ; Medeiros, Patricia M. ^[8] ; Sawakuchi, Henrique O. ^[9] ; Tank, Suzanne ^[10] ; Kerherve, Philippe ^[4] ; Rontani, Jean-Francois ^[1]

Afiliação do(s) autor(es)

^[1] Univ Toulon & Var, Aix Marseille Univ, CNRS, IRD, MIO UM 110, F-13288 Marseille - France

^[2] Aix Marseille Univ, CNRS, IRD, Coll France, CEREGE BP80, F-13545 Aix En Provence - France

^[3] Inst Radioprotect & Surete Nucl, PSE ENV SRTE LRTA, BP3, F-13115 St Paul Les Durance - France

^[4] Ctr Format & Rech Environm Mediterraneens CEFREM, UMR CNRS UPVD 5110, 52 Ave Paul Alduy, F-66860 Perpignan - France

^[5] CSIRO Oceans & Atmosphere Flagship, GPO Box 1538, Hobart, Tas 7001 - Australia

^[6] Univ Florida, Dept Geol Sci, Box 112120, Gainesville, FL 32611 - USA

^[7] Pacific Northwest Natl Lab, Marine Sci Lab, 1529 West Sequim Bay Rd, Sequim, WA 98382 - USA

^[8] Univ Georgia, Dept Marine Sci, Athens, GA 30602 - USA

^[9] Univ Sao Paulo, Ctr Nucl Energy Agr, Av Centenario 303, BR-13400970 Piracicaba, SP - Brazil

^[10] Univ Alberta, Dept Biol Sci, Edmonton, AB T6G 2E9 - Canada

• Tipo de documento: Artigo Científico
• Fonte: Organic Geochemistry; v. 115, p. 78-92, JAN 2018.
• Citações Web of Science: 7

Resumo

There exists a substantial amount of research on abiotic (e.g. photochemical) degradation pertaining to organic matter (OM) in the marine realm. While recent research has shown its importance in the degradation of terrestrial particulate OM (TPOM), the mechanisms involved in the induction of autoxidation in estuaries remain unclear. In this study, we propose for the first time the involvement of lipoxygenase (LOX) activity in the induction of autoxidation in mixed waters. The observation of unusual profiles of palmitoleic acid oxidation products and the presence of jasmonic acid in suspended particulate matter (SPM) collected close to the Rhone River, as well as in samples from the Mackenzie and Amazon rivers, is attributed to strong LOX activity. We show the role played by salinity in the induction of this LOX activity and provide an explanation for the differences in estuarine autoxidation level. At high latitude, lower temperatures and irradiance favor photooxidative damage to higher plant debris and, consequently, hydroperoxide production. High hydroperoxide content strongly contributes to LOX activation in mixed waters. The high resulting LOX activity enhances alkoxyl radical production and thus autoxidation. On the contrary, at low latitude, photooxidative effects are limited, and riverine autoxidation is favored. The higher hydroperoxide content of TPOM may, as a consequence, thereby also contribute to a high level of LOX activity and autoxidation in estuaries. In temperate zones, land and riverine photooxidative and autoxidative damage is limited, unlike estuaries where we observed significant LOX-induced and autoxidative damage. (c) 2017 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 08/58089-9 - The role of rivers on the regional carbon cycle
• Beneficiário: Maria Victoria Ramos Ballester
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático