Development of a Testate Amoebae Calibration Dataset from a freshwater wetland in a semi-arid environment: Loboi Swamp, Kenya, East Africa.

The East African Rift Valley is characterized as an arid to semi-arid region, with several large, well studied, alkaline lakes; within the region, freshwater wetlands persist. These wetland systems, locally are important sources of freshwater. They also provide overlooked important paleoclimate archives, as the fragile ecology of these wetlands can be affected by even minor changes in hydrology and climate. Loboi Swamp is a 1.5 km2 freshwater wetland located near the equator in the Kenyan Rift Valley. The region receives approximately 700 mm of precipitation per year, while potential evaporation exceeds 2500 mm annually. Analysis of 25-years of precipitation data from local weather stations indicate that significant positive precipitation anomalies occur during El Niño years. Radiocarbon, pollen, and diatom data from Loboi Swamp indicates that the current wetland developed approximately 700 years ago. Sediment surface samples were collected for pollen, seeds and testate amoebae, along with water chemistry and vegetation data from throughout the Loboi Marsh. In this paper we present preliminary data and results in the development of a calibration dataset to test the feasibility of using testate amoebae as a proxy for hydrological and geochemical changes in a semi-arid setting. Initial results indicate significant qualitative differences in testate amoebae taxon distribution within geographic regions of the marsh, which likely correlate with a variety of hydrologic parameters (e.g., alkalinity, PH, DO, and temperature).