Work in the Ottesen lab seeks to understand the structure and function of complex microbial communities, and the ways in which microbes interact with and perceive complex environments.  A major focus is the use of molecular ecological tools to observe microbial behavior in the environment.  This includes not only observing and tracking changes in which microbes are present in an environment, but also using community transcriptomics to observe changes in microbial gene expression over time.  By studying microbial behavior “in the wild”, we hope to gain a better understanding of the roles and significance of diverse members of the uncultured microbial majority. 



Microbial responses to Saharan dust deposition events in the Atlantic.

In large regions of the ocean, iron is a limiting nutrient for primary production.  Dust originating in the Saharan Desert and transported within the upper atmosphere is a significant source of iron and other nutrients to ocean surface waters in the Caribbean, southeastern US, and Gulf of Mexico.  We are examining the response of the microbial community to dust additions, using community RNA sequencing approaches to identify pathways of microbial uptake and utilization of nutrients found in Saharan dust.  


Understanding the assembly and ecological roles of stream and river microbial communities. 

Streams and rivers play key roles in global biogeochemical cycles and act as the major conduits for the movement of carbon and nutrients between land and sea.  We are exploring how streamwater microbial communities form and how this process is influenced by human impacts on the stream and the surrounding landscape.  


Exploring how gut microbial communities are shaped by diet and environment.

We (and most other higher organisms) are hosts to complex gut microbial communities that aid in digestion and help shape our overall health.  Diet is known to be a key factor in shaping gut microbial communities in many organisms.  However, we have recently found that gut community structure in omnivorous cockroaches is highly stable and resistant to perturbation by even severe dietary shifts.  We are currently studying the underlying causes of this resilience and how it impacts organismal health and behavior.