Lichen-Associated Bacterial Diversity in the Trans-Mexican Volcanic Belt
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Lichen-associated bacterial diversity in the Trans-Mexican Volcanic Belt A final report for the Explorers Club Exploration Fund, Diversa Award, 2007 Submitted April 2008 Brendan P. Hodkinson PhD Candidate, Biology Department Duke University, Durham, NC 27708 443-340-0917; [email protected] Google Earth™ view of the eastern portion of the Trans-Mexican Volcanic Belt, facing east from ~20 miles above the Valley of Mexico. Major landmarks include three volcanoes (Iztaccíhuatl, Popocatépetl, and Pico de Orizaba), a crater lake (Laguna Alchichica), and two major cities (Puebla and Xalapa). 2 In August 2007, I traveled to the biologically diverse eastern portion of the Trans- Mexican Volcanic Belt to collect fresh lichen specimens for my studies of bacterial diversity. My journey began in the city of Puebla, where I spent my first night. Nearby was the Parque Nacional Izta-Popo, home to North America’s second and third highest volcanoes, Popocatépetl (5,452 m) and Iztaccíhuatl (5,230 m). Iztaccíhuatl is the smaller of the two volcanoes, and, unlike Popocatépetl, is no longer active. Also, the peak of Iztaccíhuatl is the lowest point in Mexico with permanent snow and glaciers. This is a perfect place for sampling lichens because, in a relatively short amount of time, diverse lichen samples can be collected from a variety of elevations (at least 3,000 m of elevation change within the park). First morning in Mexico. Volcán Popocatépetl seen from the city of Puebla, with a hint of Volcán Iztaccíhuatl behind my head. 3 I then traveled to the state of Veracruz, an area that is world renown for its amazing biodiversity. I was centered at the Instituto de Ecología in Xalapa for five nights, and from there I was able to collect in nearby parks, including Parque Crustose lichens on bark by Pico de Orizaba. Nacional Pico de Orizaba (home to North America’s highest volcano at 5,636 m). The collections from this area provided me with material that can be compared with specimens collected near my home institution, Duke University, in North Parmelia sensu lato on rock near Pico de Orizaba. Carolina. During the analysis stage, I will be able to compare results based on elevation, distance, and host lichen species, to see what role, if any, these sorts of factors play in determining which bacteria live in association with lichens. Given my background in floristics, I will also be able to identify the lichens that I collect and catalogue their diversity for the ongoing study of Mexico’s native flora. A jungle ravine near Pico de Orizaba. 4 A bug walking on limestone covered with crustose lichens (Verrucaria sensu lato) by Pico de Orizaba. A spiny exoskeleton surrounded by leafy liverworts, foliose lichens, and crustose lichens in Xalapa. A foliose lichen in Xalapa (the picture on the left shows Mosses, lichens, and liverworts in Xalapa. the spore-bearing apothecia, while the one on the right shows the entire body, or thallus, of the lichen). 5 After my time in Xalapa, I headed back toward Puebla. Along the way, I stopped at Laguna Alchichica, a beautiful volcanic crater lake in the heart of the Trans-Mexican Volcanic Belt. I spent the final two days completing crucial field research and collecting in the area of Parque Nacional Izta-Popo. Ultimately, my research in the Trans-Mexican Volcanic Belt will reveal a more complete picture of the bacterial community associated with lichens. I hope that this research will aid in the preservation of lichen diversity, by giving us a better understanding of how different factors may affect lichens through their bacterial associates. Laguna Alchichica, a volcanic crater lake in the Trans-Mexican Volcanic Belt. Volcán Popocatépetl emerging from the clouds Pico de Orizaba (from Volcán Iztaccíhuatl) .