Project Title: Application of a continuous imaging flow cytometer for monitoring estuarine microplankton
Principal Investigator(s): Michael Sieracki, Christian Sieracki

Accomplishments
Scheduled Tasks:
Our primary goals for this period were to 1) end the field data collection with the removal of the instrument from the Wells Harbor town dock, 2) participate in the education/outreach workshop to be March 02 at the University of New Hampshire, and 3) collate and analyze the data to compare pre-, during, and post-dredging particle populations and phytoplankton community structure.

Progress on Tasks
Dr. Chris Sieracki participated in the March education/outreach workshop held at UNH. The FlowCAM instrument was successfully removed from the Wells Harbor dock in early April with the assistance of Scott Orringer, the Wells technician who maintained and operated the instrument there. Data was backed up onto replicate CDs.

Data has been collated and synchronized with environmental data (temperature, salinity). Data is being converted into multiple-day blocks so that tidal and diel variation can be examined over the longer (e.g. seasonal) periods of interest. These periods are the pre-, during, and post-dredge periods of similar season. We are particularly interested in the spring bloom community structure before and after the dredging since this is usually a distinctive community and may be influenced by the changed local hydrography. For example, the deepening of the channel leading to and under the Wells dock could make the high-salinity oceanic community more dominant in the area sampled. This hypothesis is being tested in the data analysis now underway. The oceanic community would be observed at high tidal periods during the pre-dredge period. The hypothesis is that this community may persist longer during the tidal cycles after dredging. Size spectra data is being calculated from defined blocks of data for community structure analysis. In the process of this calculation we get the total phytoplankton biomass and abundance as well as cell sizes. Images are being examined for dominant and distinctive phytoplankton types to qualitatively describe the communities. Categories include chain diatoms, pennate diatoms, dinoflagellates, nanoflagellates, and ciliates. This combination of descriptive and quantitative analysis is proving to be a powerful way of interpreting community changes that may have occurred due to the dredging - either direct effects observed during or at times near the dredging time, or community changes due to indirect effects such as local hydrographic changes.

Data analysis and interpretation is nearing completion and a full, final data report will be done by the November deadline.

We have gained considerable experience operating the instrument at Wells we have made many technical improvements to the instrument as a result. Improvements include better temperature control of the instrument, better data cable design, and improvements in mechanical engineering to deal with the wide tidal variations at a dock installation. Instrument optics have been improved partly as a result of limitations seen in the Wells data. We have also gained experience with the wireless Ethernet transfer of FlowCAM data from the Wells dock to the Estuarine Reserve laboratory for data backup and management. This will help with ongoing and future development of in-situ versions of FlowCAM for offshore deployment on oceanographic moorings.

Difficulties Encountered
The only issue is that the data is taking longer to analyze and interpret than we had originally anticipated.