Nutrient Sensor Challenge - Honorable Mention for Innovation and Potential for lab-on-chip sensors

The independent judging panel of the Nutrient Sensor Challenge awarded an Honorable Mention for Innovation and Potential to the National Oceanography Centre (NOC) team for their lab-on-chip (LOC) nitrate and phosphate sensors. The award was announced on 2nd March 2017 at a special session during the ASLO meeting in Hawaii.

The Nutrient Sensor Challenge was launched in December 2014 by the Challenging Nutrients Coalition and the Alliance for Coastal Technologies. The Challenge was designed to accelerate the development of reliable and affordable in situ sensors, which will enable high resolution monitoring of nitrate and phosphate in aquatic environments; from freshwater streams to the coastal ocean. Such sensors will provide the data needed to make informed management decisions to reduce nutrient loads, track progress and improve our understanding of nutrient dynamics and their impact on aquatic ecosystems over a variety time-scales. After beta testing and verification, 5 participants were selected for the final verification testing which took place in 2016.

Deployment location at Chesapeake Biological Laboratory pier, Chesapeake Bay, Maryland, USA (image courtesy of M. Grand)

The Nutrient Sensor Challenge was an unparalleled opportunity to test the latest version of NOC’s  lab-on-chip sensors under challenging field conditions. During the Challenge verification phase, the NOC sensors were deployed in freshwater (Maumee River, Great Lakes Region. 34 days), brackish water (Chesapeake Bay. 72 days) and in an oligotrophic bay in Hawaii (Kaneohe Bay. 29 days). At each site, the sensors were set to monitor nitrate and phosphate at hourly intervals. Prior to the 72-day long Chesapeake Bay deployment, the NOC sensors were also put to the test in a 1000 L tank, in order to assess their dynamic range, accuracy and precision under controlled laboratory conditions. As part of this lab testing phase, the response of the sensors was tested at the different temperatures, salinities, turbidities and dissolved organic carbon concentrations that are likely to be encountered in the field.

Left to right: Lab testing at Chesapeake Biological Laboratory (CBL), summer 2017, NOC phosphate and nitrate sensors are shown on right hand side; NOC phosphate sensor prior to 72 day deployment at CBL pier (both images courtesy of M. Grand); NOC sensors (front) deployed at the Hawaii Institute of Marine Biology in Kaneoehe Bay, Oahu, Hawaii in October 2016 (image courtesy of Daniel Schar)

The sensor data from each deployment site, including the laboratory testing, are currently being processed and analyzed. Comparison of the sensor data with discrete sample data collected by the ACT staff will help troubleshoot issues to improve the long-term reliability of the NOC sensors.