TY - JOUR
T1 - Impact of climate change on the ecology of the Kyambangunguru crater marsh in southwestern Tanzania during the Late Holocene
AU - Coffinet, Sarah
AU - Huguet, Arnaud
AU - Bergonzini, Laurent
AU - Pedentchouk, Nikolai
AU - Williamson, David
AU - Anquetil, Christelle
AU - Gałka, Mariusz
AU - Kołaczek, Piotr
AU - Karpińska-Kołaczek, Monika
AU - Majule, Amos
AU - Laggoun-Défarge, Fatima
AU - Wagner, Thomas
AU - Derenne, Sylvie
PY - 2018/9/15
Y1 - 2018/9/15
N2 - Instrumental records of temperature and hydrological regimes in East Africa evidence frequent droughts with dramatic effects on population and ecosystems. Sources of these climatic variations remain largely unconstrained, partly because of a paucity of Late Holocene records. Here, we present a multi-proxy analysis of a 4-m continuous sediment core collected in the Kyambangunguru crater marsh, in southwest Tanzania, covering the last 4000 yrs (cal. BP). We used microscopic (macro-remains, microfossils, palynofacies, pollen), elemental (carbon, nitrogen contents), molecular (br GDGTs, n-alkanes) and compound-specific isotopic (δ2H n-alkanes) investigations to reconstruct the environmental history of the marsh. The multi proxy record reveals that, 2500 years ago, the marsh underwent a major ecological transition from a lake to a peatland. Temperature and hydrological reconstructions evidence warmer and drier conditions between 2200 and 860 cal. BP, which probably triggered the establishment of a perennial peatland. This study is one of the first combined temperature and precipitation record of Late Holocene in the region and highlights changes in the spatial distribution of the East African climate regimes. Several cold periods are observed, between 3300 and 2000 cal. BP and since 630 cal. BP, the latter corresponding to the Little Ice Age. Moreover, wetter conditions are reported during the Medieval Climate Anomaly in contrast to other north-eastern African records suggesting that Tanzania is located at the transition between two hydro-climatic zones (north-eastern versus southern Africa) and has experienced variable contributions of these two zones over the last millennium.
AB - Instrumental records of temperature and hydrological regimes in East Africa evidence frequent droughts with dramatic effects on population and ecosystems. Sources of these climatic variations remain largely unconstrained, partly because of a paucity of Late Holocene records. Here, we present a multi-proxy analysis of a 4-m continuous sediment core collected in the Kyambangunguru crater marsh, in southwest Tanzania, covering the last 4000 yrs (cal. BP). We used microscopic (macro-remains, microfossils, palynofacies, pollen), elemental (carbon, nitrogen contents), molecular (br GDGTs, n-alkanes) and compound-specific isotopic (δ2H n-alkanes) investigations to reconstruct the environmental history of the marsh. The multi proxy record reveals that, 2500 years ago, the marsh underwent a major ecological transition from a lake to a peatland. Temperature and hydrological reconstructions evidence warmer and drier conditions between 2200 and 860 cal. BP, which probably triggered the establishment of a perennial peatland. This study is one of the first combined temperature and precipitation record of Late Holocene in the region and highlights changes in the spatial distribution of the East African climate regimes. Several cold periods are observed, between 3300 and 2000 cal. BP and since 630 cal. BP, the latter corresponding to the Little Ice Age. Moreover, wetter conditions are reported during the Medieval Climate Anomaly in contrast to other north-eastern African records suggesting that Tanzania is located at the transition between two hydro-climatic zones (north-eastern versus southern Africa) and has experienced variable contributions of these two zones over the last millennium.
KW - Holocene
KW - Paleoclimatology
KW - East Africa
KW - Continental Biomarkers
KW - Organic geochemistry
KW - stable isotopes
KW - Palynology
U2 - 10.1016/j.quascirev.2018.07.038
DO - 10.1016/j.quascirev.2018.07.038
M3 - Article
SN - 0277-3791
VL - 196
SP - 100
EP - 117
JO - Quaternary Science Reviews
JF - Quaternary Science Reviews
ER -