TY  - JOUR
A1  - Wolff, Christian Michael
A1  - Kristen-Jenny, Iris
A1  - Schettler, Georg
A1  - Plessen, Birgit
A1  - Meyer, Hanno
A1  - Dulski, Peter
A1  - Naumann, Rudolf
A1  - Brauer, Achim
A1  - Verschuren, Dirk
A1  - Haug, Gerald H.
T1  - Modern seasonality in Lake Challa (Kenya/Tanzania) and its sedimentary documentation in recent lake sediments
JF  - Limnology and oceanography
N2  - From November 2006 to January 2010, a sediment trap that was cleared monthly was deployed in Lake Challa, a deep stratified freshwater lake on the eastern slope of Mt. Kilimanjaro in southern Kenya. Geochemical data from sediment trap samples were compared with a broad range of limnological and meteorological parameters to characterize the effect of single parameters on productivity and sedimentation processes in the crater basin. During the southern hemisphere summer (November-March), when the water temperature is high and the lake is biologically productive (nondiatom algae), calcite predominated in the sediment trap samples. During the "long rain" season (March-May) a small amount of organic matter and lithogenic material caused by rainfall appeared. This was followed by the cool and windy months of the southern hemisphere winter (June-October) when diatoms were the main component, indicating a diatom bloom initiated by improvement of nutrient availability related to upwelling processes. The sediment trap data support the hypothesis that the light-dark lamination couplets, which are abundant in Lake Challa cores, reflect seasonal delivery to the sediments of diatom-rich particulates during the windy months and diatom-poor material during the wet season. However, interannual and spatial variability in upwelling and productivity patterns, as well as El Nino-Southern Oscillation (ENSO)-related rainfall and drought cycles, exert a strong influence on the magnitude and geochemical composition of particle export to the hypolimnion of Lake Challa.
Y1  - 2014
U6  - https://doi.org/10.4319/lo.2014.59.5.1621
SN  - 0024-3590
SN  - 1939-5590
VL  - 59
IS  - 5
SP  - 1621
EP  - 1636
PB  - Wiley
CY  - Waco
ER  -