Open AccessMajor changes in glacial and Holocene terrestrial temperatures and sources of organic carbon recorded in the Amazon fan by tetraether lipids
Author(s) -
Bendle James A.,
Weijers Johan W. H.,
Maslin Mark A.,
Sinninghe Damsté Jaap S.,
Schouten Stefan,
Hopmans Ellen C.,
Boot Christopher S.,
Pancost Richard D.
Publication year - 2010
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2010gc003308
Subject(s) - amazon rainforest , last glacial maximum , holocene , glacial period , geology , sediment , drainage basin , earth science , carbon cycle , climate change , amazonian , total organic carbon , physical geography , oceanography , geomorphology , ecology , ecosystem , geography , cartography , biology
The Amazon basin is a major component of the global carbon and hydrological cycles, a significant natural source of methane, and home to remarkable biodiversity and endemism. Reconstructing past climate changes in the Amazon basin is important for a better understanding of the effect of such changes on these critical functions of the basin. Using a novel biomarker proxy, based on the membrane lipids of soil bacteria with a new regional calibration, we present a reconstruction of changes in mean annual air temperatures for the Amazon catchment during the last 37 kyr B.P. Biomarkers were extracted from Ocean Drilling Program sediment core ODP942 recovered from the Amazon fan. The Amazon fan is a major depository for terrestrial sediments, with the advantage that the terrestrial material captured reflects a regional integration of the whole river catchment. The reconstructed tropical Amazonian temperatures were ∼5°C cooler at the Last Glacial Maximum (∼21°C) compared to modern values (∼26°C). This is in agreement with previous estimates of tropical continental temperatures in the tropical Amazon basin and tropical Africa during the Last Glacial Maximum. Moreover, we also illustrate how the soil bacterial membrane lipid record reveals major changes in basin dynamics and sediment provenance during the glacial‐Holocene transition, impacting the biomarker reconstructions from ∼11 kyr onward.