Quantifying the Effects of Warming and Ecosystem Change on Arctic Soil Microbial Communities
Abstract
Increases in arctic temperatures have accelerated microbial activity and thawed permafrost, liberating long-frozen substrates that result in positive soil-climate feedbacks. Additionally, aboveground changes in the tundra such as shrub encroachment and altered litter quality have led to changes in soil microbial processes. Quantifying the response of each microbial taxon to increased temperature and ecosystem change can offer a more detailed ecological understanding of how climate change alters these processes. To do this, quantitative stable isotope probing (qSIP) incubations using 18O water were conducted at the Toolik Field Station in Alaska. To uncouple the effects of warming and ecosystem change, active layer soil was incubated in situ for 10 and 30 days in each of the following treatments: 3 months warming, 29 years warming (warming and ecosystem change), and unwarmed controls. Native water was removed through desiccation and then rewetted to match the original water content with either 98.5 atom percent 18O oxygen water or natural abundance water. This is one of the first attempts to perform a qSIP experiment in the field, and the first from arctic soil. Over 90% of the native water was removed and replaced, achieving exceptional 18O enrichment in all samples. Total density curves of 16S gene copies shifted in 18O-labelled samples, but weighted average density was not significantly different in warming treatments. Our results suggest either that tundra soil prokaryotic communities are unaffected by warming and ecosystem treatments, even after 30 days of incubation, or that effects are not detectable on the community scale. Only a small portion of community members may have been affected by the treatments. Identification of labelled taxa reveals how much these microbes respond to warming and warming-associated ecosystem changes. Overall, our research offers a glimpse into which soil microbes will thrive in a warming arctic.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B53G2476P
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0448 Geomicrobiology;
- BIOGEOSCIENCES;
- 0454 Isotopic composition and chemistry;
- BIOGEOSCIENCES;
- 0465 Microbiology: ecology;
- physiology and genomics;
- BIOGEOSCIENCES