NOAA/WDS Paleoclimatology - Lake Malawi 700 Year TEX86 Surface Water Temperature Reconstruction

We have applied the TEX86 paleothermometer to produce a surface water temperature record for Lake Malawi spanning the past 700 years. Over much of the record temperature fluctuates from ~24-27°C with a mean of ~25°C; however, there has been a substantial increase in temperature of ~2.0°C during the past ~ 100 years. The TEX86 temperature record reveals a strong similarity to the instrumental record; both records demonstrate warming (~0.7-1.4°C) over the past ~50 years as well as a cooling anomaly around 1959. Comparison of the TEX86 temperature record with the proxy records of primary productivity suggests that wind induced upwelling and/or precipitation have a strong influence on the surface temperature of Lake Malawi. Surface water 700 year temperature reconstruction for Lake Malawi, East Africa, produced using the TEX86 paleothermometer. Three cores collected during the 1998 International Decade for East African Lakes (IDEAL) expedition in the north basin of Lake Malawi were used in this study. Splicing data from multi-cores M98-11MCA and M98-11MCB, and gravity trigger core M98-2PG, results in a record spanning the past ~700 years. Sediment samples (~1-2 g dry weight) were collected from the cores and analyzed for TEX86 as described in Powers et al. (2005). We have applied the mean annual lake surface temperature (ALST) calibration equation, ALST=55.0*TEX86-14.0 Lake Malawi core M98-11MCA/B: 10°00.2'S, 34°17.3'E, water depth 404m. Lake Malawi core M98-2PG: 9°58.6'S, 34°13.8'E, water depth 363m.