Oceanic particles consisting of a variety of inorganic material, organic detritus, and living organisms, densely populate the world’s oceans. They encompass a diverse range of shapes and vary in size from sub-microns (e.g., picoplankton)to a few cm (e.g., colonial diatom chains). Due to their ubiquitous presence, they influence areas of interest spanning aspects of ocean sciences as diverse as sediment transport, marine ecology, climate change, remote sensing, and ocean optics. For example, quantification of sediment resuspension and transport by waves and currents in coastal bottom boundary layer environments are critical to coastal engineering applications. A key aspect of climate change studies is understanding how oceans act as sinks for anthropogenic carbon, where the absorbed organic carbon is transported by sinking particulate matter from the upper ocean to the seabed through a process known as the “biological pump”. The inherent optical properties (IOPs), which control the propagation of light in water are strongly influenced by the composition of local particulate matter. Remote sensing relies on interpreting the signature of back-scattered light from the ocean to detect algal biomass, “thin layers” with high phytoplankton concentration, suspended particle mass, and to quantify biological primary productivity. Thus, characterizing oceanic particulates based on type, size, and shape is critical to several oceanographic applications. A part of my research focuses on developing and using instrumentation (e.g. holographic imaging) to study particle fields in aquatic environments.
Collage of particles/plankton seen in holographic images from oceanic deployments of an in situ holographic imaging system.