Event Title

Seasonal fluctuations of multiple lake characteristics influence bacterial dormancy in the Great Salt Lake

Presenter Information

Tylan Magnusson

Location

ECC 201/203 & 205/207

Event Website

https://water.usu.edu/htm/conference/2013conference

Start Date

9-4-2013 5:55 PM

End Date

9-4-2013 6:05 PM

Description

Bacteria in extreme environments often evolve to contend with one dominant stress, but may be exposed to huge temporal fluctuations and other environmental characteristics. In lake ecosystems, bacteria have developed life strategies, such as dormancy, to survive seasonal oscillations in temperature and C substrate quantity and quality. It remains unclear, however, if bacteria in extreme environments experience dormancy or how the community changes in response to seasonal fluctuations. We measured microbial dormancy patterns during one year in the northern ([salt]= 25855.0 ppm) and southern ([salt]= 20920.0 ppm) arms of the Great Salt Lake and related dormancy to seasonal fluctuations in the dominant stress factors: salinity, dissolved oxygen and temperature. For our study, we defined dormancy as the difference between DNA-based communities (i.e., all bacteria present in the community) and RNA-based communities (only the active bacteria) and used targeted metagenomics to analyze the 16S rDNA and rRNA extracted from lake water samples. We hypothesized that temporal variability in salinity will be the primary driver of microbial dormancy but temperature and dissolved oxygen will also relate to dormancy patterns. Seasonal variation in salinity strongly related to microbial dormancy in both arms of the Great Salt Lake demonstrated by a positive linear relationship (R2 = 0.98 P <0.01) between the ratio of rDNA to rRNA taxa and salinity. Additionally, as dissolved oxygen levels increased, dormancy declined (R2 = 0.67 P =0.01), suggesting that the availability of O2 drives the activity of specific lake bacteria taxa. Seasonal temperature fluctuations did not relate to dormancy patterns (R2 = 0.01 P =0.54). Our findings suggest that even though one dominant stress may define which bacteria reside in an extreme environment, other environmental drivers have the potential to structure bacterial community composition and induce seasonal shifts in bacterial dormancy.

 
Apr 9th, 5:55 PM Apr 9th, 6:05 PM

Seasonal fluctuations of multiple lake characteristics influence bacterial dormancy in the Great Salt Lake

ECC 201/203 & 205/207

Bacteria in extreme environments often evolve to contend with one dominant stress, but may be exposed to huge temporal fluctuations and other environmental characteristics. In lake ecosystems, bacteria have developed life strategies, such as dormancy, to survive seasonal oscillations in temperature and C substrate quantity and quality. It remains unclear, however, if bacteria in extreme environments experience dormancy or how the community changes in response to seasonal fluctuations. We measured microbial dormancy patterns during one year in the northern ([salt]= 25855.0 ppm) and southern ([salt]= 20920.0 ppm) arms of the Great Salt Lake and related dormancy to seasonal fluctuations in the dominant stress factors: salinity, dissolved oxygen and temperature. For our study, we defined dormancy as the difference between DNA-based communities (i.e., all bacteria present in the community) and RNA-based communities (only the active bacteria) and used targeted metagenomics to analyze the 16S rDNA and rRNA extracted from lake water samples. We hypothesized that temporal variability in salinity will be the primary driver of microbial dormancy but temperature and dissolved oxygen will also relate to dormancy patterns. Seasonal variation in salinity strongly related to microbial dormancy in both arms of the Great Salt Lake demonstrated by a positive linear relationship (R2 = 0.98 P <0.01) between the ratio of rDNA to rRNA taxa and salinity. Additionally, as dissolved oxygen levels increased, dormancy declined (R2 = 0.67 P =0.01), suggesting that the availability of O2 drives the activity of specific lake bacteria taxa. Seasonal temperature fluctuations did not relate to dormancy patterns (R2 = 0.01 P =0.54). Our findings suggest that even though one dominant stress may define which bacteria reside in an extreme environment, other environmental drivers have the potential to structure bacterial community composition and induce seasonal shifts in bacterial dormancy.

http://digitalcommons.usu.edu/runoff/2013/AllPosters/8