TY - JOUR
T1 - Paleolimnological investigations of anthropogenic environmental change in Lake Tanganyika
T2 - II. Geochronologies and mass sedimentation rates based on 14C and 210Pb data
AU - McKee, Brent A.
AU - Cohen, Andrew S.
AU - Dettman, David L.
AU - Palacios-Fest, Manuel R.
AU - Alin, Simone R.
AU - Ntungumburanye, Gerard
N1 - Funding Information:
We thank the Global Environmental Facilities’ Lake Tanganyika Biodiversity Project and the US National Science Foundation (ATM9619458) for financial support of this research. We especially thank Drs Andy Menz, Graeme Patterson and Kelly West for their extensive support in all aspects of this project, and the crew of the R/V Tanganyika Explorer, especially Captain Kimosa and Robert Makere for their tireless efforts on behalf of this work. We gratefully acknowledge the Tanzanian Council for Scientific Research (COSTECH), the Tanzanian Fisheries Research Institute (TAFIRI), and the University of Burundi, for their support of this research program. This is contribution #165 of the International Decade of East African Lakes (IDEAL).
PY - 2005/7
Y1 - 2005/7
N2 - We established sediment geochronologies for cores from eight deltaic areas in Lake Tanganyika (the Lubulungu, Kabesi, Halembe, Malagarasi, Nyasanga/Kahama, Mwamgongo, Nyamusenyi, and Karonge/Kirasa River deltas), recording a range of watershed disturbance histories from the eastern margin of this African rift valley lake. Cores from currently disturbed sites on the central Tanzanian coast display remarkably uniform and low rates of sediment accumulation from the 18th century until the early 1960s, when a synchronous and dramatic rise in rates occurs. Through this same time interval sedimentation rates offshore from undisturbed Tanzanian watersheds either remain unchanged or decline. Further north, at disturbed sites along the northern Tanzania and Burundi coasts, the pattern of sedimentation rate increase is more complex. Although a mid-late 20th century increase is also evident in these sites, indications of earlier periods of increasing sediment erosion, dating from the mid-late 19th century, are also evident. Synchronous changes in sediment accumulation rates dating from the early 1960s may be the result of exceptionally wet years triggering an increase in the discharge of previously eroded and unconsolidated alluvium and stream/beach terrace deposits, previously accumulated in the deltas and stream valleys of impacted watersheds. Sedimentation rate impacts of deforestation on lake ecosystems are likely modulated by short-term climatic forcing events, which can impact the specific timing and location of sediment discharge to lakes.
AB - We established sediment geochronologies for cores from eight deltaic areas in Lake Tanganyika (the Lubulungu, Kabesi, Halembe, Malagarasi, Nyasanga/Kahama, Mwamgongo, Nyamusenyi, and Karonge/Kirasa River deltas), recording a range of watershed disturbance histories from the eastern margin of this African rift valley lake. Cores from currently disturbed sites on the central Tanzanian coast display remarkably uniform and low rates of sediment accumulation from the 18th century until the early 1960s, when a synchronous and dramatic rise in rates occurs. Through this same time interval sedimentation rates offshore from undisturbed Tanzanian watersheds either remain unchanged or decline. Further north, at disturbed sites along the northern Tanzania and Burundi coasts, the pattern of sedimentation rate increase is more complex. Although a mid-late 20th century increase is also evident in these sites, indications of earlier periods of increasing sediment erosion, dating from the mid-late 19th century, are also evident. Synchronous changes in sediment accumulation rates dating from the early 1960s may be the result of exceptionally wet years triggering an increase in the discharge of previously eroded and unconsolidated alluvium and stream/beach terrace deposits, previously accumulated in the deltas and stream valleys of impacted watersheds. Sedimentation rate impacts of deforestation on lake ecosystems are likely modulated by short-term climatic forcing events, which can impact the specific timing and location of sediment discharge to lakes.
KW - Deforestation
KW - East Africa
KW - Lake Tanganyika
KW - Late Holocene
KW - Mass accumulation rates
KW - Soil erosion
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U2 - 10.1007/s10933-005-2395-3
DO - 10.1007/s10933-005-2395-3
M3 - Article
AN - SCOPUS:21044446168
SN - 0921-2728
VL - 34
SP - 19
EP - 29
JO - Journal of Paleolimnology
JF - Journal of Paleolimnology
IS - 1
ER -