An ocean observatory sensor network application

We describe our implementation of a novel deep ocean sensor network, the MBARI Free Ocean CO₂ Enrichment (FOCE). FOCE is a system designed for installation in the deep ocean to enable manipulative experiments that explore the impact of deep ocean increase in CO₂ and resulting pH change on ocean biogeochemistry and ecology. This system uses control feedback and pH sensors to inject CO₂ into a small volume of seawater, thus creating a controlled environment per science requirements. To implement this system, we utilized the MBARI-developed network middleware known as "SIAM", which provides a standardized interface to instruments on a sensor network. For the FOCE application we integrated Open Source DataTurbine (OSDT) into SIAM. OSDT provides asynchronous communication links between distributed components, and is particularly well-suited to streaming instrument data. Combined with the existing synchronous SIAM framework, these features enabled a straightforward and efficient architecture for our application. We describe how we achieved our goals of software reuse of infrastructure and instrument services, instrument-in-the-loop control, and rapid assembly of a scalable end-to-end sensor network system.