Date of Award
Master of Science in Oceanography
Achieving depth-resolved particle-specific data in sparse, highly variable oceanic environments persists as a methodological challenge. Holography has emerged as a tool for in-situ imaging of microscopic organisms and other particles in the marine environment; appealing because of the relatively larger volume and simple optical configuration compared to other imaging systems. The digital in-line holographic microscope (DIHM) used in this study samples ~100× larger volumes than comparable objective lens-based systems, and is deployable on CTD-rosette, flow-through, and autonomous systems. However, it’s quantitative capabilities have so far, remained uncertain. Here, the quantitative skill of the DIHM to evaluate size and concentration of marine particles ranging from 5 to 1000 μm in diameter is assessed. Over one million particles are analyzed using a custom image processing pipeline, which allows a precise characterization of the three-dimensional volume sampled. These results are compared with the FlowCam, the Imaging FlowCytobot and traditional microscope counts through laboratory and field-based inter-calibration experiments. Based on this analysis, recommendations for achieving quantitive size and concentration measurements from the DIHM are suggested.
Walcutt, Noah L., "An Assessment of Holographic Microscopy for Quantifying Marine Particle Size and Concentration" (2018). Open Access Master's Theses. Paper 1328.
Available for download on Monday, July 27, 2020