Developing the First Operational Nutrient Observatory for Ecosystem, Climate, and Hazard Monitoring for NERACOOS

Abstract

An integrated nutrient observatory is being developed within the Northeastern Regional Association of Coastal Ocean Observing Systems (NERACOOS), capable of monitoring nutrient dynamics year-round at temporal and spatial scales necessary to address critical needs of stakeholders throughout the Northeast region. Nutrient levels and fluxes drive total biological productivity throughout the region, from phytoplankton to commercially exploited fish stocks. Nitrate sensors (Satlantic SUNAs) are being installed on existing mooring assets in western Long Island Sound, Narragansett Bay (Prudence Island), Great Bay in New Hampshire, Massachusetts Bay, three sites along the coastal shelf of the Gulf of Maine (GOM), at five depths in Jordan Basin in the interior GOM, and at two depths in the GOM Northeast Channel. Phosphate and ammonium sensors (WET Labs Cycle-PO4 and Cycle-NH4) are also being deployed at the three nearshore sites. The measurements from these sensors will extend the current sparse, long-term records of nutrients from discretely collected samples in the Northeast region and will dramatically improve temporal resolution and continuity of the data for use in studying potential impacts of climate change. Nearshore measurements will be used by NERACOOS stakeholders to help assess, regulate, and mitigate the adverse impacts on water quality associated with excessive pollutant loadings. Measurements throughout the GOM will be used to assess basin-wide nutrient variability and to initialize harmful algal bloom (Alexandrium fundyense) forecast models.

A Droplet Microfluidic-Based Sensor for Simultaneous in Situ Monitoring of Nitrate and Nitrite in Natural Waters

“…An alternative way to monitor nitrate and nitrite is by using wet chemical sensors. These sensors operate on similar principles to laboratory autoanalysers: pulling a water sample in, performing a chemical assay, and then recording or relaying the result using on-board electronics. − By the careful engineering of fluidic manifolds and control systems, the whole system can be miniaturized into a small integrated field-deployable package (“sensor”), with commercial systems available (e.g., Systea WIZ, Seabird Scientific HydroCycle-PO 4 , ). Recent academic developments of wet chemical sensors have focused on reducing channel dimensions to a few hundred microns or less (“microfluidic sensors”) to improve fluid and power efficiency by reducing the fluidic volume and hence the required liquid volume and pumping .…”