Environmental Influences on the Genetic Diversity of Bacterial Communities in Arctic Streams

• Main Author: Larouche, Julia
• Format: Text
• Language: unknown
• Published: UVM ScholarWorks 2009
• Subjects: arctic streams; Arctic; Alaska
• Online Access: https://scholarworks.uvm.edu/graddis/131; https://scholarworks.uvm.edu/context/graddis/article/1130/viewcontent/Larouche_20doc.pdf

The National Park Service (NPS) Inventory and Monitoring (I&M) Program is designed to collect baseline data on “vital sign†indicators across the entire NPS system. The project presented in this thesis was designed to supplement to efforts of the Artic Network (ARCN) to catalogue the physical, chemical and biological metrics associated with the Stream Communities and Ecosystems vital sign and to foster a better understanding of the basic structure and function of these remote systems. This data is essential to assess the impacts of current and future environmental change in the ARCN parks. The primary objective of this project was to quantify the genetic diversity of microbial communities of selected arctic stream ecosystems. Microbes are a fundamentally important but poorly understood component of arctic stream ecosystems. They are responsible for recycling organic matter and regenerating nutrients that are essential to the food webs of aquatic ecosystems. Recent research (Jorgenson et al. 2002) in the ARCN parks has shown that two fundamentally different lithologies – ultramafic and non-carbonate – influence terrestrial productivity and impart different geochemical characteristics to stream water. Microbes are found in different stream habitats – sediment (epipssamon) and rock (epilithon) biofilms. In this work we test the hypothesis that these differences in lithology and stream habitat influence the genetic diversity of bacterial biofilm communities in arctic streams and whether these patterns can be correlated to stream biogeochemistry. A microbial community fingerprinting method, T-RFLP, as well as 16S rRNA gene sequencing were used to explore the genetic diversity of microbial communities in sediment and epilithic biofilms in stream reaches that drain watersheds with contrasting lithologies in the Noatak National Preserve, Alaska. Differing patterns in bacterial community composition at both the large-scale (lithology) and small-scale (stream habitat) were observed. Non-metric ...