Activity and growth rates of bacteria in the environment

 

Prokaryotic organisms in marine systems are highly diverse and carry out many types of metabolic processes important in biogeochemical cycles. However, the contribution of individual bacterial taxa to biochemical processes is not well understood. Estimates of growth rates will help understand both problems. The contribution of specific bacterial taxa to biogeochemical cycles is likely to scale with growth rate as well as abundance, and these rates are also likely to be more sensitive to environment fluctuations than abundance.

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We use a combination of metagenomics/metatranscriptomics and qPCR approaches to examine levels of 16S rRNA and other growth-regulated transcripts as well as their corresponding genes in both cultured marine bacteria and uncultured bacteria under various nutrient conditions and different in situ temporal and spatial scales. Growth-­responsive transcript: gene ratios, microbial abundance, and biogeochemical properties are being examined over hourly, daily, weekly and monthly time scales to investigate the influence of environmental factors on growth rates of individual bacterial taxa and to explore bottom-­up control of microbial communities
 

Study Site 

 

Delaware and Chesapeake Bays, coastal Atlantic Ocean

 

Current and Former Lab Participants

 

Alvee Ahmed, Jason Gholamian, Louie Alexander, Margi Patel, Emily Castelloe, Ludovic Besaury, Nattasha Vinas, Caleb Ahrns, Keith Thompson, Milap Patel, Eric Jakubowski

 

Presentations/Papers

 

Maresca et al., 2018, Campbell and Kirchman, 2013,

Campbell and Kirchman, ISME, 2012, Campbell et al., 2011

 

Funding

 

NSF, Growth rates of bacterial taxa in coastal marine ecosystems. PI with co-PI DL Kirchman, University of Delaware