Sedimentary bacterial community dynamics are one of the remaining “black boxes” in ecology. Recent accessibility of molecular biology technologies has allowed for a new focus on the microbiology of ecosystem research. Our study used bacterial counts and rRNA sequence analysis to explore the effects of nutrient loading on the bacterial community composition of intertidal sediments across a salinity gradient in an estuarine system in mid-coast Maine.
Results/Conclusions

There was no consistent response in bacterial abundance to the addition of either nitrogen or phosphorous. Initial review of bacterial community composition as described by sequencing of 16s rRNA genes indicated an increase in proteobacteria, often with a resulting decrease in number of phyla with nutrient addition. These data will also allow for description of community composition across a salinity gradient. The strength of the community composition response may be dampened by past and present nutrient pollution, especially phosphorous, which may still be affecting the system.