Microscopic charcoals in ocean sediments off Africa track past fire intensity from the continent - Réseau télédétection INRAE Access content directly
Journal Articles Communications Earth & Environment Year : 2023

Microscopic charcoals in ocean sediments off Africa track past fire intensity from the continent

Abstract

Abstract Fires in Africa account for more than half of global fire-carbon emissions but the long-term evolution of fire activity and its link to global climate change remains elusive. Paleofire records provide descriptive information about fire changes through time, going beyond the range of satellite observations, although fire regime characteristics are challenging to reconstruct. To address this conceptual gap, we report here the abundance and morphometric data for a large set of microscopic charcoal samples ( n = 128) recovered from surface ocean sediments offshore Africa. We show that in subtropical Southern Africa, large and intense fires prevailing in open savanna-grassland ecosystems produce a high abundance of small and elongated microcharcoal particles. In contrast, in the forest ecosystems of equatorial and tropical regions of western and central Africa, low-intensity fires dominate, producing low amounts of squared microcharcoal particles. Microcharcoal concentration and morphotype in marine sediment records off Africa are thus indicative of fire regime characteristics. Applied to down-core marine charcoal records, these findings reveal that at orbital time-scale intense and large, open grassland-savanna fires occurred during wet periods in the sub-tropical areas. A strong contribution of fire carbon emissions during periods of precession and summer insolation maxima in the geological record is thus expected.
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hal-04082024 , version 1 (28-04-2023)

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Aritina Haliuc, Anne-Laure Daniau, Florent Mouillot, Wentao Chen, Bérangère Leys, et al.. Microscopic charcoals in ocean sediments off Africa track past fire intensity from the continent. Communications Earth & Environment, 2023, 4 (1), pp.133. ⟨10.1038/s43247-023-00800-x⟩. ⟨hal-04082024⟩
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