| 1. |
- Goni, Maria Fernanda Sanchez, et al.
(författare)
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The ACER pollen and charcoal database : a global resource to document vegetation and fire response to abrupt climate changes during the last glacial period
- 2017
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Ingår i: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 9:2, s. 679-695
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Tidskriftsartikel (refereegranskat)abstract
- Quaternary records provide an opportunity to examine the nature of the vegetation and fire responses to rapid past climate changes comparable in velocity and magnitude to those expected in the 21st-century. The best documented examples of rapid climate change in the past are the warming events associated with the Dansgaard-Oeschger (D-O) cycles during the last glacial period, which were sufficiently large to have had a potential feedback through changes in albedo and greenhouse gas emissions on climate. Previous reconstructions of vegetation and fire changes during the D-O cycles used independently constructed age models, making it difficult to compare the changes between different sites and regions. Here, we present the ACER (Abrupt Climate Changes and Environmental Responses) global database, which includes 93 pollen records from the last glacial period (73-15 ka) with a temporal resolution better than 1000 years, 32 of which also provide charcoal records. A harmonized and consistent chronology based on radiometric dating (C-14, U-234/Th-230, optically stimulated luminescence (OSL), Ar-40/Ar-39-dated tephra layers) has been constructed for 86 of these records, although in some cases additional information was derived using common control points based on event stratigraphy. The ACER database compiles metadata including geospatial and dating information, pollen and charcoal counts, and pollen percentages of the characteristic biomes and is archived in Microsoft Access (TM) at https://doi. org/10.1594/PANGAEA. 870867.
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| 2. |
- Hessler, Ines, et al.
(författare)
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Millennial-scale changes in vegetation records from tropical Africa and South America during the last glacial
- 2010
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 29:21-22, s. 2882-2899
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Tidskriftsartikel (refereegranskat)abstract
- To reconstruct the response of vegetation to abrupt climate changes during the last glacial we have compiled pollen records from the circum-Atlantic tropics between 23 degrees N and 23 degrees S from both marine and terrestrial sediment cores. Pollen data were grouped into mega-biomes to facilitate the comparison between the different records. Most tropical African records do not appear to register Dansgaard-Oeschger (D-O) variability, although there are vegetation changes during Heinrich Stadials (HS). There is a stronger signal of D-O and HS variability in the South American records. Records close to the modern northern and southern limits of the Intertropical Convergence Zone (ITCZ) show opposite trends in vegetation development during HS and D-O cycles. The pollen data from tropical South America corroborate the hypothesis of a southward shift in the migration pattern of the ITCZ and a reduction in the Atlantic Meridional Overturning Circulation (AMOC) during HS.
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| 3. |
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| 4. |
- Ryner, Maria, et al.
(författare)
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Vegetation changes in Empakaai Crater, northern Tanzania, at 14,800–9300 cal yr BP
- 2006
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Ingår i: Review of Palaeobotany and Palynology. - 0034-6667. ; 140, s. 163-174
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Tidskriftsartikel (refereegranskat)abstract
- Vegetation changes are documented from a well-dated pollen record from Lake Emakat, Empakaai Crater, northern Tanzania.This pollen record includes the time interval covering the Pleistocene/Holocene transition, analysed at a resolution intervalaveraging 200 yr. Around the crater lake, an Hagenia-forest development starting at 14,500 cal yr BP lasted until 13,000 cal yr BP.A change in vegetation, indicated by an increased proportion of Nuxia congesta in the forest and Artemisia in the afro alpinegrassland after 13,000 cal yr BP, corresponds in time to the Northern Hemisphere's Younger Dryas cooling. Grasses and sedgesincreased at ∼10,100 cal yr BP, indicating a significant increase in local pollen possibly attributed to lowered lake level, related todrier conditions. Although the Empakaai pollen record documents continuous forest conditions, from 14,500 to 10,100 cal yr BP,the variation in the proportion of forest components seem to respond to environmental changes at the millennium scale
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