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Seasonal dynamics of amoebae population in the Zygophyllum dumosum rhizosphere, Negev Desert, Israel.
Rodriguez-Zaragoza, Salvador*,1,2, Ojalvo-Mayzlish, Einav1, Steinberger, Yosef1, 1 Faculty of Life Sciences, Bar-Ilan, Ramat-Gan, Israel2 Facultad de Estudios Superiores Iztacala, UNAM, Tlalnepantla, Estado de Mexico, Mexico
ABSTRACT- Water availability and nutrient limitation are the most important driving forces in hot desert ecosystems. These two forces determine the vegetation cover and biological activities -trophic group composition- which promote soil nutrient availability and its turnover. Soil protozoa -ciliates, flagellates and amoebae- play an important role in mineralization processes. Free-living amoebae are one of the main groups known to be microbial grazers in soil, as they easily move in and between pore soil spaces due to their elasticity and lack of rigid structures. However, despite their importance in nutrient recycling, the population dynamics of soil amoebae is poorly known. The aim of this study was to evaluate the seasonal changes of free-living amoebae population in the rhizosphere of Zygophyllum dumosum and in the shrubs interspace -as control- at 0-10 cm and 10-20 cm soil layer. The total number of amoebae was determined in each soil sample in winter, spring, summer and autumn, using the most probable number technique. A significant difference in total numbers of amoebae was found between the soil samples taken in Z. dumosum rhizosphere and the control samples throughout the seasons. There was no statistically significant difference between the two depths under Z. dumosum. These results elucidate the importance of the plant rhizosphere as being an important source of organic matter and soil moisture mediator enhancing biotic activity.
KEY WORDS: Desert Ecosystem, Soil Amoebae, Zygophyllum dumosum, Seasonal Population Dynamic