Project: An Autonomous Ocean Profiling and Water Sampling System for 0 to 11 km of Water Depth

NSF Award Abstract:
This project will build an autonomous system that measures physical, chemical and biological properties and samples seawater throughout the full global range of ocean depths (0 to 11 km below sea level). Because this system will be deployable over this entire depth range, it will significantly advance understanding of deep-sea chemistry, watermass structure and planktonic ecosystems at all water depths. Because the system will profile and sample deep water autonomously, it will replace human-guided wire-based operations for oceanic profiling and water sampling at any depth. Consequently, it will significantly reduce the time and expense required for on-site operations by allowing shipboard science parties to undertake other deck operations simultaneously with water-column sampling and profiling. Most uniquely, the proposed system will make pervasive study of the very deep (6000-11000 mbsl) ocean feasible for the first time. At completion of this project, the system will be made available to the scientific community as a shared-use instrument.

This autonomous system will profile the physical and chemical properties of the entire water column during the trip from sea surface to seafloor and back again. During the return trip, it will take up to 24 water samples with modified Niskin bottles and pressure-retaining water samplers. Sampling strategies will be flexible and easily programmed to autonomously take samples at specific depth horizons (e.g., 10 depths spaced between 100 and 10000 meters) or adaptively based on transitions recorded and automatically identified in salinity, temperature, density or oxygen content. The system will be tested in the laboratory and at sea on two trial expeditions in the second project year. The trial expeditions for this system will provide field opportunities, samples and data for scientists and students to study deep-sea biological, chemical and physical processes in the western North Atlantic and a deep-sea trench (probably the Puerto Rico Trench). The expeditions will focus on creating opportunities for students from URI and minority-dominated institutions, especially in Puerto Rico, where the second expedition may begin and end. The project will introduce undergraduate and graduate students to design of oceanographic instruments and sea-going research through: (i) an Ocean Engineering design class based on the proposed instrument development, (ii) inclusion of undergraduate and graduate students on the expeditions, (iii) ship tours and presentations in the port region(s), (iv) study by other graduate students of samples and data from the expeditions. Finally, the project will provide a stipend and tuition for graduate student training in scientific instrument design and software development. These efforts will address NSF Broader Impact criteria in several ways, including participation of women, persons with disabilities, and underrepresented minorities in science, technology, engineering, and mathematics (STEM) and development of a diverse, globally competitive STEM workforce.