A high-resolution 11,400-Yr diatom record from Lake Victoria, East Africa

Fine-interval (∼30-45 yr) sampling of a core from Lake Victoria's Damba Channel shows that numerous abrupt changes in the lake's diatom assemblages have occurred in response to climatic fluctuations over the past 11,400 ¹⁴C yr. Four distinct climatic phases bounded by sudden transitions are inferred: (1) variably dry ∼11,400-10,000 yr B.P., (2) humid ∼10,000-7200 yr B.P., (3) more seasonal ∼7200-2200 yr B.P., and (4) more arid ∼2200-0 yr B.P., with a dry "Little Ice Age" event ∼600-200 yr B.P. The diatom-inferred paleoclimatic history for northern Lake Victoria closely resembles that inferred from a well-dated pollen record from Pilkington Bay. Spectral analysis of the diatom record reveals strong periodicities including globally distributed ∼2360-2550, ∼1400, ∼1030-1130, and ∼500 cal-yr cycles. Repeated, rapid shifts between Aulacoseira- and Nitzschia-dominated diatom assemblages suggest that post-1960 changes in the lake's phytoplankton communities have had earlier, climate-driven analogs.