Salt marshes have long been known to provide many essential ecosystem services but recently they have received renewed attention because of their very high rates of carbon sequestration and their possible use for carbon offsets.  Marshes represent an attractive strategy for mitigating increased atmospheric CO2 concentrations because they can both fix CO2 directly into biomass and they can trap organic carbon that is advected laterally into marshes via tidal and riverine inputs. 

This organic matter also provides ample substrate for another essential marsh service – the removal of fixed nitrogen via microbially-mediated denitrification.  Marshes can remove considerable amounts of anthropogenic nitrogen via this pathway, thereby helping to ameliorate the threat of eutrophication.  It is clear that microbes contribute significantly to these critical ecosystem services and it is also clear that salt marshes are under pressure both from rising sea levels and increased human perturbations on land.  Much work is needed to understand how these disturbances alter the structure and function of microbial communities.

Marsh restoration projects provide a unique experimental opportunity to answer key unknowns regarding how microbial community structure and function are altered by disturbance while simultaneously generating useful information that can be translated into improving restoration practices. We are studying a series of marshes on Cape Cod and in the greater Boston area to address the following questions:

1.   How does a rapid change in salinity alter the structure and function of microbial communities?  

2. Do microbial communities undergo directed succession in much the same way plant communities do and does their geochemical function follow?  

3. How do changes in plant genotypic and taxonomic diversity alter marsh microbial diversity?