By: Prajoth Pattamatta
Dr. Steve Baker
November 22, 2011
The research experiment observed and analyzed the differences in microbial diversity between lichen on bare rocks and hairy cap mosses in the annual community. Samples from three different sites were taken from Mount Arabia in Georgia, and were analyzed in lab. The results from the data collected showed that greater microbial diversity was present in hairy cap moss than in lichen, with a greater percentage of growth for each colony. This could be the result of the mutual symbiotic relationship that bacteria share with hairy cap moss, a greater source of nutrients available for bacteria in hairy cap moss in soil than in lichen on bare rock, or due to the temperature differences between the two sites being sampled. Introduction
Lichen, or Cladonia sp., is a plant that is made up of algae, bacteria and fungi. Lichen is a composite symbiotic organism that thrives in regions that have extreme temperatures, such as arctic tundra and hot deserts (Pace, 1997). The hairy cap moss species, or Polytrichum commune, is one of the more than 15,000 species of moss present in nature. Hairy cap moss is a medium sized moss that is prevalent in areas that have high levels of humidity. The purpose of this research project was to investigate the differences in microbial diversity between lichen on bare rocks and hairy cap mosses in the annual community. Based on background information, a hypothesis was formed that lichen on bare rocks will have greater microbial diversity compared to that in the hairy cap mosses. From the hypothesis, it was predicted that if lichen on bare rocks has greater microbial diversity than hairy cap mosses in the annual perennial community, then the total number of species, colony types and the relative abundances of the species collected from lichen on bare rocks will be greater than hairy cap mosses. Once the experimental procedure was formed, the samples were collected from Mount Arabia, a small mountain located in DeKalb County, Georgia, and analyzed in a laboratory setting. Materials and Methods
The two-part procedure involved in this research project comprised of collecting the samples of the two rock outcrop species, and after a week of incubation, the analysis of the samples in lab. The samples of lichen and hairy cap moss were collected from three different rock outcrop sites at Mount Arabia, along with the temperature and soil depth data for each location. The rock outcrop sites that were sampled contained both species within close proximity to each other. The samples were taken using the sterile technique and spotted into agar plates, once for each species at each location.
The samples in the plates were incubated for a week and were then analyzed in lab. Each agar plate was analyzed for the presence of bacteria. Once the bacterial colonies were identified and differentiated from fungi, each colony was categorized based on their size, shape and color. The bacteria samples were placed onto microscope slides and observed using a light microscope to categorize their shape and motility. Results
In order to compare the microbial diversity between the rock outcrop species of lichen and hairy cap moss, samples of the two species were collected at Mount Arabia and incubated on agar plates. According to the temperature readings, a trend was seen where the temperature of the lichen on the bare rock was higher for each of the sample sites. At sample site 1, the lichen on the rock had a temperature reading that was 3.5°c. At sample site 2, the reading was 2.5°c higher for the temperature of the lichen, and at sample site 3, there was a 5.8°c difference between the two readings. Table 1. Temperature and Soil Depth Measurements at Each Sample...