ALLISON SCHAAP: Lab-on-chip sensors for autonomously measuring nutrients and carbonate parameters

Natural waters are vital for life on earth and yet are often inadequately understood due partly to the difficulty and cost of accessing open water for sampling.  To address this, we develop microfluidic sensors which autonomously perform in situ measurements of water chemistry.  We combine optics, microfluidics, chemistry, and custom-engineered hardware to create sensors which can be deployed for months at a time thanks to their low reagent and power consumption. 

In this presentation I’ll first give an overview of our general sensor platform, which has been implemented to measure a wide range of chemical parameters including nitrate, phosphate, and pH.    Some recent deployments – from the arctic to the tropics – will be used to illustrate the current capabilities and long-term potential of this technology.

The second part of the presentation will focus in on one of our newest sensors as a case study: an alkalinity sensor.  Alkalinity is a measurement of the capacity of water to buffer against changes in pH and is thus a key parameter for monitoring and modelling ocean acidification and the carbon cycle.  The scientific applications of this sensor require reliable accuracy (~0.1%) during deployments lasting months in harsh and varying conditions.  Developed for a project on carbon capture and storage, the sensor has been deployed for the first time in the past year.  The results from lab tests and preliminary results from the sea trials show that the technology is in a strong position to be able to meet these demands.

Lastly, I’ll discuss some of the engineering challenges that we’ve faced in creating technology that has to survive at sea, lessons we’ve learned, and the group’s future plans for the technology.