Microcharcoal calibration in recent marine sediments: implications to reconstruct paleofire regimes on African continent

Abstract:

Fire is one of the most important terrestrial disturbance agents with impact on ecological processes, atmospheric chemistry and the global cycle and is responsible for shaping the Earth system since millions of years. The fire regime metrics such as burned area, intensity, frequency, is influenced by complex climatic and environmental variables including fuel type and availability, ignition and human dimension, such as land-use. Therefore, in the context of current and anticipated climate warming scenarios, the projected changes in temperature, precipitation and increase of anthropogenic activities are expected to increase fire occurrence, severity with consequences on the environment and human society. Despite the recent scientific advances, there are still large deficiencies in understanding the interaction between fire and other components of the Earth system and thus, limitations in integrating this process in global models.

Marine paleofire records inform about relative changes in the level of biomass burning over long timescale and can help understanding the relationships between climate change and fire activity. However, we still miss what represent a change in biomass burning in the paleorecord in term of fire regimes on the continent. The present study aims at exploring the link between charcoal accumulation in marine surface sediment samples of modern ages from over 150 sites across the African coast and fire regimes on land, based on an integrated approach using fire proxy, climate, environmental and historical information, and satellite data. This exploratory study is designed to interrogate this link among different biomes and to test the influence of different physical site-specific variables on land (climate, vegetation, size of the source area etc.), transport and deposition processes into the marine realm.

With this study, we intend to deliver a novel sediment-based proxy for a key physical parameter unlocking specific technical and theoretical problems related to fire research; it may further help to a better understanding of the local to regional processes that govern the fire signal and also contextualize current and past environmental changes.

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