Investigating Hot Spring Outflow Channels Using A Combination of Geochemical and Microbiological Analyses in Yellowstone National Park
Abstract
Hot spring outflow channels provide vast geochemical gradients, such as pH gradients of ~2 units, and temperature gradients spanning ~45°C. For context, a 45°C temperature difference is approximately the same between the average year-round temperature at the equator (18°C) and the average summertime temperature at the South Pole (-28.2°C). Microbial life can take advantage of geochemical gradients as a source of energy. To investigate the relationship between geochemical gradients and microbial diversity we performed water chemistry measurements and 16S rRNA gene sequencing along the outflow channels of 12 hot springs in Yellowstone National Park (YNP). Often along hot spring outflow channels there is a transition from chemosynthetic communities near the source to photosynthetic communities downstream. Therefore, microbiome samples for this investigation were collected below, at and above the photosynthetic transition, or "photofringe". We calculated energy supplies for ten chemotrophic reactions commonly used by hot spring microbes using measured concentrations of dissolved solutes. Changes in energy supply and microbiome composition were analyzed using NMDS, indicating a positive correlation between ammonia and nitrite oxidation energy (p < 0.05 for both) and microbiome composition across the photofringe. Alpha diversity was also analyzed across the photofringe using Faith Phylogenetic Diversity. The diversity values suggest diversity is higher at the photofringe of acidic hot springs (pH 1.9 to 5.8, n=16) to compared to at the photofringe of alkaline hot springs (pH 7.6 to 9.0, n=17), 16.4 versus 8.0. Additionally, alpha diversity is lower at the photofringe of alkaline hot springs compared to samples taken below the photofringe, 8.0 versus 15.6. By combining geochemical and microbiological analyses with energy calculations, we report new insights concerning the relationship between energy supplies, microbial community composition, and alpha diversity down hot spring outflow channels.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.B35O1593W