Development of a Fiber Optic UV Flurorometer for Autonomous Underwater Vehicles

Objectives:Our objective is to develop a compact, in situ, fiber optic UV fluorometer to enable high resolution measurement of dissolved organic matter (DOM), petroleum hydrocarbons, chlorophyll and other fluorescent tracers in seawater. We will demonstrate that the incorporation of this sensor into a mobile platform such as an autonomous underwater vehicle (AUV) will aid in assessing the distribution, transport, and fate of such substances in marine environments. Currently, the spatial and temporal resolution of studies of important physical, geochemical, and biological processes (e.g. plume dynamics, contaminant mixing and transport, degradation or removal, sediment water exchange, and phytoplankton blooms) are limited by the costs of sample collection and laboratory analysis. The combination of an in situ sensor and a high performance low cost AUV promises to dramatically reduce the cost of obtaining a synoptic picture of these heterogeneous processes. Methodology:The research plan is to design the fluorometer and to carry out initial sensor characterization in the lab. The instrument will then be incorporated into a glass sphere and further characterized. By packaging the fluorometer into a standard glass sphere, we obtain a package that can quickly installed into any Odyssey IIb AUV. Finally, an Odyssey II AUV (with the fluorometer installed) will be deployed in Boston Harbor. Rationale:Incorporation of this sensor into a mobile platform such as an autonomous underwater vehicle (AUV) will aid in assessing the distribution, transport, and fate of contaminants off the coast of Massachusetts. Currently, studies of important physical and geochemical processes such as plume dynamics, mixing, and sediment water exchange are limited in their spatial and temporal resolution by the expense of sample collection and laboratory analysis. The combination of an in situ sensor and a high performance, low cost AUV promises to dramatically reduce the cost of obtaining a synoptic picture of these heterogeneous processes. Measurements will also be enabled under hazardous, and typically undersampled, conditions such as storms and oil spills. While the unit will be designed for use in the MIT AUV Odyssey II, it will be capable of operating on a wide variety of platforms, including instrumented moorings and benthic landers.