The purpose of this trip was to establish sampling sites for a survey of supra-tidal freshwater pool bacterioplankton communities. In collaboration with Juniper Simonis (Grad Student, Ecology & Evolutionary Biology), we sampled approximately 20 pools to understand the diversity of microorganisms. The samples were taken back to the lab and compared by Automated rRNA Intergenic Spacer Analysis (ARISA). The results showed that each sample was distinct. Based on this, we designed experiments to be conducted during the next sampling trip, in June.

Ian traveled to Shoals in June 2009 to initiate an experiment with Juniper Simonis (Grad Student Ecology & Evolutionary Biology) examining the impact of DOC on bacterioplankton communities in mesocosms. This involved extracting HMW DOC from tannin-rich waters of an island reservoir, then adding this back to mesocosms containing a standardized bacterioplankton community and water source. We ran the experiment for 21 days, and collected additional samples from supratidal pools to establish temporal variation in individual pools. The analyses included chlorophyll a, physicochemical conditions, bacterial abundance, and microbial DNA, which we later analysed by ARISA.

The first official outing of the Hewson Lab into the field together occurred during 2 weeks in July 2009. The purpose of this trip was to conduct several experiments: 1) a mixing experiment of freshwater and seawater to examine which components of bacterioplankton responded more rapidly to environmental change; 2) a virus addition experiment to see what happened when viral pressures were increased 10 fold upon bacterioplankton metatranscriptomics (community gene expression); 3) collect a time series of bacterial DNA from the dock, and along a transect from Portsmouth, NH to Old Scantum, Gulf of Maine; 4) collect copepods and other zooplankton for analysis of associated viruses. Despite horrible weather (see photos), we collected > 200 individual samples and transported them home safely to Ithaca.

Publications from this expedition:

Simonis JL, Neuharth-Keusch D, Hewson I (2012) “Aquatic bacterial assemblage variability in the supra littoral zone of Appledore Island, Gulf of Maine” FEMS Microbiology Ecology 80: 501-508

Brown JM, Felice NR, Scalfone, NB, Hewson I (2012) “Influence of habitat confluence on aquatic microbial assemblages in experimental mesocosms” Aquatic Microbial Ecology 66: 33-40