Automated Oxygen Titrator for the Scripps Oceanographic Data Facility

About This Grant

The objective of this project is to update and advance an instrument necessary to conduct the trusted measurement of the concentration of dissolved oxygen in seawater by US and other international hydrographic programs. The Scripps Oceanographic Data Facility, a technical group operating under the Scripps Ship Operations and Marine Technical Support division and organized under Shipboard Technical Support, is responsible annually for thousands of measurements of dissolved oxygen performed on research vessels, while at sea, on bottles collected using classic hydrographic sampling techniques and measurement protocols. The majority of these measurements are for NSF funded programs and projects and constitute the reference-quality oxygen data for virtually all of the major NSF-funded global hydrography efforts that are the foundation of widely used databases. This award will allow continuation and improvement of these efforts through critical updates to a system that is ageing into obsolescence. Over the past 35 years Scripps has replicated and supported these oxygen titration systems for other oceanographic laboratories around the world. Many of these groups intend to either replicate the new design or hire Scripps to construct it through a service agreement. Leading the new design will allow Scripps to continue its role as an international leader in the collection and quality control of hydrographic oxygen data. As done for the past five years, technical experts will continue to interact with undergraduates, where students are given the opportunity to visit the laboratory and observe and, under supervision, operate the oxygen titration system. The methods employed to reach the project objective include the engineering of a new optical and control system, new component qualification, and extended testing both on-shore and at-sea. Full system qualification requires operation of the new system alongside an operational legacy system for extended periods. The project will modernize the hardware and software used to perform the classic Winkler titration method for determining dissolved oxygen concentration in seawater. In the process of updating an obsolete (but historically very well performing) system, this effort will capitalize on modern components and also merge two well-established methods (determination by direct absorbance and titration) into one system. The resulting system will maintain the outstanding measurement accuracy and precision achieved through titration by the previous generation instrument. The new system will be capable of a rapid direct measurement of dissolved oxygen concentration across the full oceanographic range (by direct absorbance), before the titration is performed. With its updated optical components, the system will require less user intervention and improve reliability during regular operation. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.