Anne Ola - 9 décembre 2019 - Université Laval

Anne Ola, stagiaire postdoctorale au Département des sciences du bois et de la forêt à l’Université Laval. The roots of Blue Carbon. Mangroves store large amounts of organic carbon (C) in their soils and are important in the global C cycle. These C stocks have been attributed to slow decomposition rates and high below ground productivity, yet there is limited knowledge about the environmental factors that influence mangrove root growth. Several glasshouse and field experiments were performed to assess the effect of soil bulk density on mangrove below ground traits. Additionally, a litter bag study was conducted to understand the role of variation in soil bulk density on C cycling in mangrove forests. It was found that plant functional traits are strongly influenced by variation in soil bulk density, but the effect was species specific. Generally, dense soils reduced root lengths and increased total root biomass, as well as root diameters. However, decomposition rates were found to decrease with increases in soil bulk density experienced by the roots during growth, possibly due to the effect of soil bulk density on the development of root structural features. Decomposition rates also differed among mangrove species. The pattern was largely reflected in N levels, C:N ratios and lignin content. Hence, soil bulk density likely has major implications for the C sequestration potential of mangrove forests, as soil bulk density not only influences the quantity of the soil organic matter inputs, but also their quality, hence decomposability.

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