Saint Bickolard Mabicka Iwangou

IRT/CENAREST, Gabon

Title: Modification of the chemical composition and the natural durability of Avicennia germinans mangrove tree of the Estuary region of Gabon exposed to marine hydrocarbons pollution

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Biography

Dr Saint Bickolard Mabicka Iwangou is an expert in Wood Sciences with a profound understanding of mangrove ecosystems. His thesis on the pollution of mangroves in Libreville, Gabon, showcases his deep knowledge of both terrestrial and mangrove wood formation. As a Research Associate at LaReVa Bois, he is pioneering research on the impacts of mineral and organic pollution on mangroves, focusing on their chemical, anatomical, and ecophysiological changes.

Abstract

Mangroves develop both near the sea and inland. However, mangroves that develop inland are more exposed to urban pollution, as is the case of the mangroves of the Ambowé lagoon in Greater Libreville. Yet mangroves play a very important ecological role. Among other things, they protect coastlines from erosion, serve as nurseries and breeding grounds for numerous species of fish and shellfish, and are the carbon sink. Hence, the impact of the anthropogenic pollution stress of fishing engine oils so called hydrocarbons pollution on the chemical, microstructure and natural durability of Avicennia. germinans (L.)L. from Ambowé mangrove of the Estuary region of Gabon was studied. The results were compared with samples from Oveng and Mamboumba, two unpolluted sites of Libreville. Dichloromethane and hexane soluble extractives content decreased significantly (p <0.05) in the polluted heartwoods, 5 ±0,007 % et 2.11 ±0,2 %, respectively. Confocal microscopy revealed for the first time the occurrence of rays and vessels opening in the polluted heartwood which could explain the loss of some extractives. That loss of extractives was supported by UV where a dramatic decrease of extractives was observed in the heartwood exposed to pollutants. These changes on extractives content and wood microstructures would explain the high mass loss of the polluted heartwood exposed to Trametes versicolor (35.69 ±6.27 %) and Rhodonia placenta (11.65 ±6.62%) these rot fungi provoked only mass losses <10 and 5 %, respectively for the unpolluted heartwoods.