Holocene environmental dynamics in coastal, eastern and central Amazonia and the role of the Atlantic sea-level change

Abstract

Several pollen records from selected sites of coastal, eastern and central Amazonia are summarised and compared to provide insights in Holocene environmental changes. The hydrology of Amazonian wet- lands, especially those in the eastern part of the Basin, is strongly influenced by the Atlantic sea-level. Sea-level rise in the early Holocene stabilized at near modern levels at ca. 8300 cal BP (calibrated radiocarbon years before present), reflected by the first occurrence of mangroves at the present-day coastal line. The retreat of mangroves after about 7750 cal BP reflects a lower relative sea-level. The modern mangroves developedmostly about 4500 cal BP or somewhat later at the pre- sent-day coastline. First impact of early Holocene sea- level rise in the Amazon Basin is found by the change of an active to a passive (lake-like) river system about 8900 cal BP Later, local Mauritia palm swamps devel- oped along river margins in central and eastern Ama- zonia. This stage is probably a regional phenomenon for the whole low lying Amazon Basin. First varzea and igapo forests (seasonally inundated forests) devel- oped at that time as well, but their size was still small. In eastern and central Amazonia, marked increase of varzea/igapo forests is documented since mid- to late Holocene. The development of huge seasonally inun- dated areas must have had an important influence on the Amazonian water and carbon cycle and the regional climate in Amazonia. © Author(s) 2011. This work is distributed.