Abstract
Fire causes dramatic energy and matter exchanges between the biosphere and atmosphere. The complex feedbacks between climate and vegetation complicates understanding how fire interacts with environmental changes (Archibald et al., 2018). Multiproxy paleo-records integrating these three critical parts of the Earth system are necessary to go beyond the short modern observational records and asses the role of fire in large-scale and long-term ecological changes.
Fire regime characteristics (such as frequency and intensity) are an important concept in describing fire (Bond and Keeley, 2005; Gill, 1975). Combining sedimentary charcoal and combustion-derived molecular markers (such as polycyclic aromatic hydrocarbons and monosaccharide anhydrates) is a promising way of more detailed fire regime reconstructions (Engling et al., 2014; Schüpbach et al., 2015). Their parallel detection allows not only reconstructing past fire frequency but also assessing fuel types and burning intensity.
Here we present polycyclic aromatic hydrocarbons (PAHs) together with charcoal data from a sediment core retrieved off East Java covering the past 22,000 years. Analyses of the monosaccharide anhydrates (levoglucosan, mannosan and galactosan) will be performed according to Schreuder et al. (2018). The results will be integrated with those presented here.
During the Last Glacial Maximum (22 to 18 kyrs before present), both high charcoal counts and total PAH concentrations indicate frequent fire occurrence. The dominance of low molecular weight PAHs implies relatively small fires, associated with lowland grass expansion and an extended dry season during that time. The last deglaciation (18 to 12 kyrs before present) is characterised by lower PAH concentrations but higher proportions of high molecular weight PAHs, implying a period of rare but more intense fires. Such a fire regime did not hamper the transition of the lowland vegetation from savannah into rainforest. The overall low charcoal counts and PAH concentrations during the Holocene indicate a low fire occurrence, probably due to the fire-resistance of closed-canopy vegetation.
The balance between frequency and intensity of fires observed spatially in modern ecology (Archibald et al., 2013; Murphy et al., 2013) thus likely is reflected in the temporal evolution of fire regimes in East Java.
Fire regime characteristics (such as frequency and intensity) are an important concept in describing fire (Bond and Keeley, 2005; Gill, 1975). Combining sedimentary charcoal and combustion-derived molecular markers (such as polycyclic aromatic hydrocarbons and monosaccharide anhydrates) is a promising way of more detailed fire regime reconstructions (Engling et al., 2014; Schüpbach et al., 2015). Their parallel detection allows not only reconstructing past fire frequency but also assessing fuel types and burning intensity.
Here we present polycyclic aromatic hydrocarbons (PAHs) together with charcoal data from a sediment core retrieved off East Java covering the past 22,000 years. Analyses of the monosaccharide anhydrates (levoglucosan, mannosan and galactosan) will be performed according to Schreuder et al. (2018). The results will be integrated with those presented here.
During the Last Glacial Maximum (22 to 18 kyrs before present), both high charcoal counts and total PAH concentrations indicate frequent fire occurrence. The dominance of low molecular weight PAHs implies relatively small fires, associated with lowland grass expansion and an extended dry season during that time. The last deglaciation (18 to 12 kyrs before present) is characterised by lower PAH concentrations but higher proportions of high molecular weight PAHs, implying a period of rare but more intense fires. Such a fire regime did not hamper the transition of the lowland vegetation from savannah into rainforest. The overall low charcoal counts and PAH concentrations during the Holocene indicate a low fire occurrence, probably due to the fire-resistance of closed-canopy vegetation.
The balance between frequency and intensity of fires observed spatially in modern ecology (Archibald et al., 2013; Murphy et al., 2013) thus likely is reflected in the temporal evolution of fire regimes in East Java.
Original language | English |
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Title of host publication | 29th International Meeting on Organic Geochemistry, IMOG 2019 |
Publisher | European Association of Geoscientists and Engineers, EAGE |
Pages | 1-2 |
Number of pages | 2 |
ISBN (Electronic) | 9789462823044 |
DOIs | |
Publication status | Published - 2019 |
Event | International Meeting on Organic Geochemistry (IMOG) 2019 - Gothenburg, Sweden Duration: 1 Sept 2019 → 6 Sept 2019 Conference number: 29th |
Publication series
Name | 29th International Meeting on Organic Geochemistry, IMOG 2019 |
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Conference
Conference | International Meeting on Organic Geochemistry (IMOG) 2019 |
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Abbreviated title | IMOG 2019 |
Country/Territory | Sweden |
City | Gothenburg |
Period | 1/09/19 → 6/09/19 |