News & Events

Noon seminar - The effect of climate on formation of sediments in a tropical meteorite crater lake

Monday, October 25, 2010, 12:00PM - 1:00PM


Megan Otu

INSTAAR postdoctoral scholar


ARC 620

There is a tremendous need to understand climate patterns over West Africa, a region devastated by frequent and prolonged drought. There are few meteorological or environmental records in existence for West Africa, however sediment records from Lake Bosomtwe, Ghana may be a prime candidate in understanding regional climate trends. Lake Bosomtwe is a tropical crater lake formed one million years ago by a meteorite impact. The lake is known to act like a rain gauge, where lake levels are controlled by the delivery of precipitation relative to rates of evaporation. In 2004, the International Continental Scientific Drilling Program recovered the complete 1 million year sediment record for paleoclimatic reconstructions, yet, there has been little study of the present day climate patterns in relation to the limnology and sedimentation patterns in the basin. This presentation will examine recent meteorological data, water column profiles, sediment trap samples and short gravity cores from Lake Bosomtwe, with particular attention to the organic matter δ13C and δ15N. Results show that seasonal mixing patterns significantly alter annual primary production and delivery of organic matter to the sediments.