Improved Methodology for Semi-Automated Identification of Plankton and Biovolume Estimation Using a Digital Imaging Flow Cytometer (FlowCam)

Responding to the need for the "rapid counting, imaging and measurement of individual plankton cells…in natural populations", researchers at the Bigelow Laboratory for Ocean Sciences in 1999 built and installed the first FlowCam, an imaging particle analyzer designed specifically to support aquatic microbial research. Since 1999 over 300 FlowCams in 40+ countries have been put to use for the purpose of the study and monitoring of microorganisms in both fresh and marine systems. Building upon advances in technology, input from the user community, and expanded resources, engineers at Fluid Imaging Technologies, manufacturer of the FlowCam, have designed the 4th Generation FlowCam. Informally referred to as the `High Sensitivity FlowCam' (HSFC), the instrument provides more precise information over earlier versions - especially with regard to fluorescence data and size and concentration information. The HSFC has an improved method for sample introduction, and is simpler to use. Included among the next-gen FlowCams is an optics configuration (specific laser and optical filters) allowing for the detection of phycocyanin, thus providing for an improved method to identify and characterize cyanobacteria, and a version that can analyze zooplankton up to 5mm in size. In addition to a hardware overhaul, the image recognition algorithm and user interface for identifying and classifying organisms has been redesigned, as has the method to estimate biovolume. Included will be an overview of the various new designs, how they work, along with a review of data from the HSFC FlowCam.