This project combines expertise in prokaryotic, viral, and eukaryotic microbiology from three institutions to establish a microbial observatory at Boiling Springs Lake (BSL), an acidic (pH 2.2), hydrothermal (52 degrees centigrade) lake in Lassen Volcanic National Park, CA. BSL is the largest hot spring in North America, and it is geochemically distinct from springs in Yellowstone National Park and elsewhere. BSL is a stable thermal feature of Lassen Park, yet varies significantly over both time and space, thus offering a unique opportunity to investigate factors that control the abundance, diversity, and activities of microorganisms in natural habitats, and their stability over time. A remotely operated vehicle designed and built by undergraduate engineering students will be used to map the lake's physical structure, and scientists will sample two thermally distinct regions of BSL to assess biological and chemical variation at various temporal and spatial scales. Genetic and taxonomic diversity of prokaryotes, eukaryotes and viruses, their productivity, and the relative contributions of chemosynthesis and photosynthesis to primary production will be explored by both culture-dependent and -independent approaches.
Extreme environments such as BSL are ideal for the study of fundamental questions in microbial biology since they represent low diversity communities, and also are models for life on other planets. A major goal of this proposal is to introduce undergraduates from three institutions to microbial biology, and to scientific research. During this funding period, this work will be integrated into 5 classes impacting at least 700 undergraduate students, and an additional ~100 undergraduates will be directly involved in BSL-related research projects. This project will also contribute to graduate student training, as well as outreach to high school students. The project will conduct yearly Lassen Volcanic National Park (LNVP) symposia involving the investigators, their students, park personnel, and community members, and produce a web-based database of results for the science community and the public. In addition, students will be involved in producing a color brochure for LVNP visitors, highlighting the structure, chemistry, and biology of this unique lake, and giving the public a deeper appreciation of the microbial world.
This collaborative project involving investigators and students at three universities sought to describe the physical, chemical and biological characteristics of an oligotrophic, acidic hot spring known as Boiling Springs Lake (BSL) in Lassen Volcanic National Park in northern California. Using molecular and culture-based approaches, we examined the diversity, stability and functions of prokaryotic, eukaryotic, and viral communities in the lake. Numerous organisms were cultivated and preserved in culture collections at our universities, including novel genera in all three domains of life. Additionally, we explored the antibiotic resistome in the lake, and began an investigation into the potential role of horizontal gene transfer in the evolution and function of the BSL community. We obtained genome sequences for 2 of our novel archaeal isolates, one multi-drug resistant bacterial isolate that exhibited extensive horizontal gene transfer, and one protist isolate, a heterolobosean that is the major grazer in BSL. This is the first attempt to comprehensively examine the eukaryotic community and food web structure of a geothermal environment. We also examined the potential for fungal enzymes in cellulosic biofuel production. Our activities allowed us to propose a qualitative model for nutrient cycling in the lake (Fig. 1), and a quantitative model of the hydrological & carbon budgets for the system (Fig. 2). Such integrative studies are lacking in the published literature and provide new insights into ecosystem level processes in extreme habitats. Our research efforts have lead to the discovery of a new type of RNA:DNA hybrid virus in BSL (Diemer and Stedman 2012). This finding has generated great interest, with over 33,000 accesses of the article since it was published, and the award of BioMedCentral Research Prize for best paper in the 250 BioMedCentral journals from 2012. Our data have contributed new insights into the role of oligotrophy as a major selective feature of this habitat, and suggest that low nutrients may be as important in shaping community structure as are the high temperature and low pH constraints in BSL. Our multi-locus sequence analysis of BSL isolates suggests that horizontal gene transfer (of housekeeping genes) is common in this system. To our knowledge, this has not been reported previously, and our ongoing work seeks to address whether this is a hallmark of low species richness ecosystems, or whether it is related to the low nutrient conditions in this habitat. Our work has also revealed that members of the Firmicutes phylum (esp. Alicyclobacillus spp.) seem to be important r-strategists in the system. Most of our isolates from the lake require low nutrient levels for optimal growth. Alicyclobacillus spp. appear to play an important role in the C cycle by rapidly utilizing nutrient inputs thereby returning BSL to its oligotrophic state. While endospore formers are widely distributed across most habitats investigated on Earth, their role in secondary production in oligotrophic habitats has not been reported. As an RUI project, student research training and mentoring was a critical component of our activities. Collectively, we trained 3 Ph.D., 14 Master’s, 85 undergraduate and 11 high school students in research activities related to the scientific goals of this project; nearly 2/3 of these students were female, and one quarter were from URM groups. Approximately half of the mentored undergraduate students have gone on to further training in graduate, medical, or pharmacy school, and the majority of the other students are currently working in related research or technical fields. Additionally, the grant activities have been integrated into undergraduate and graduate courses at all three institutions impacting approximately 550 students per year, or nearly 3300 students over the duration of the project funding. Ten peer-reviewed publication have been party or wholly supported by this funding. Additionally, 2 manuscripts have been submitted and are currently in review, and we estimate the submission of 6 additional manuscripts in the current calendar year. 45 presentations have been made at national, international and regional meetings, and the PIs have given 33 invited talks related to this project at (mostly) local venues. Findings related to this project have also contributed to 19 outreach/educational presentations and products, including the provision of 2000 copies of a 16 pg. color brochure entitled "Life in Boiling Acid" that were distributed in the Lassen Volcanic National Park Visitor Center in 2008.
