Biogenic silica profiles in varved sediments from northern Lake Malawi (Nyasa),
East Africa, span the past 700 yr and reflect past primary productivity in the
overlying waters. On a centennial scale this has been influenced by lake level
and a consequent shift in the location of high diatom productivity within the
lake basin. Primary production was higher during the Little Ice Age, an arid
period from about A.D. 1570 to 1850, when lake level was about 120 m lower than
during the previous three centuries or the past 150 yr.