Microbial islands: soil microbe diversity in canopy soil patches Josh Kenchel University of California, San Diego Division of Biological Sciences EAP Tropical Biology and Conservation Program, Fall 2013 13 December 2013 ____________________________________________________________________________ ABSTRACT Decaying organic matter forms patches of soil in trees, known as “canopy soil”, which are isolated from the ground. This study sought to determine whether patterns of microbe diversity in canopy soil patches are consistent with patterns of macrospecies diversity on islands. Via microscopy, I recorded microbial morphospecies abundance in ground and canopy soil. Canopy soil contained significantly lower alpha diversity (x = 17.1) than ground soil (x = 20.35), and the similarity between the microbial communities of those pairs decreased as the distance between them increased. Ground-canopy pairs were significantly more similar (x = 0.37) than pairs of ground soil samples (x = 0.22) and pairs of canopy soil samples (x = 0.21). I found no significant difference in species evenness or beta diversity between ground soil and canopy soil. The data indicate that canopy soil patches limit the number of species that can inhabit them. However, the separation between ground and canopy soil may not actually form a barrier to microbial movement. ____________________________________________________________________________ RESUMEN La materia orgánica que se descompone en los árboles forma áreas de suelo llamadas “suelo de dosel”, que están separadas de la tierra. Este estudio trató de determinar si la diversidad de microorganismos en el suelo de dosel es similar a la diversidad de macroespecies encontradas en islas. Usando el microscopio, conté especies de microorganismos en el suelo de dosel y de la tierra. Había menos especies en el suelo de dosel (x = 17.1) que en el suelo de la tierra (x = 20.35), y la semejanza entre los dos disminuyó cuando la distancia entre los dos creció. Los pares de tierra-dosel era más similares (x = 0.37) que los pares de suelo de la tierra (x = 0.22) o los pares de suelo de dosel (x = 0.21). Las diferencias de la diversidad beta y la igualdad de especies no eran significativas entre la tierra y el dosel. Los datos indican que el suelo de dosel no puede tener tantas especies como el suelo de la tierra. Sin embargo, la separación entre la tierra y el dosel quizás no limita el movimiento de microorganismos. ____________________________________________________________________________ Soil microbial communities are known to be a significant driving force of global biogeochemical cycles (Fitter 2005). However, compared with current documentation and understanding of macroscopic plant and animal diversity, which have been well studied, documentation and understanding of biodiversity in soil microbial communities are relatively poor (Fierer et al. 2012). In order to better understand how soil microbes fit into ecosystems, biomes, and the earth system, studies must be focused on documenting and characterizing the diversity of soil microbial communities and its relationship to space and time.