Gulf of Mexico Coastal Ocean Observing System

Following on from interagency nutrient sensor work facilitated by the Alliance for Coastal Technologies (ACT), the Gulf of Mexico Nutrient Sensor Project (GOM NSP) launched in 2019. Since 2019, the GOM NSP has integrated commercially available nutrient sensors into existing monitoring programs, testing the utility and operability of extensive, real-time nutrient monitoring arrays. The GOM NSP network of nutrient sensors and monitoring partners has been purpose-built for detection in biogeochemically distinct US Gulf estuaries. Project partnerships facilitate deployment planning and nutrient sensor operation for existing and prospective partners. QA/QC protocols standardized across the project promote integration of data products into shared data management systems.

These activities support the ongoing efforts to advance nutrient sensing in critical ecosystems such as the Gulf of Mexico. With funding from the EPA through NOAA and GCOOS, researchers in the GOM NSP are working to establish a network of in situ nutrient sensors in coastal and estuarine ecosystems along the US Gulf Coast.

Project Partnerships

Project partnerships are in varying stages of development, from planning stages (blue) to active deployment (green). Further additions to the GOM Nutrient Sensor network will seek to fill gaps in geographical coverage of the US Gulf Coast. In addition to revealing nutrient dynamics on the Gulf Coast, project partnerships build a community of knowledge around commercialized, in situ nutrient sensors and create relationships between research institutions and sensor technology companies.

Implementation Timeline

Testing New Sensing Solutions

Nutrient sensor selection takes advantage of the commercialization of affordable insitu sensors to deploy a cost-effective monitoring network. Three sensors have thus far been identified for lower cost, high accuracy nutrient detection, and we are continually looking for new entries to the market.

In general, wet chemical sensors achieve higher sensitivity and are more resistant to environmental interference, but they require more maintenance and have steeper learning curves. Optical sensors require less maintenance and are more facile to use, but they may be CDOM, salinity, and/or turbidity-limited and tend to have less sensitive detection limits, relative to wet chemical technologies.

The three sensors that will be tested in this phase are TriOS OPUS (optical nitrate sensor), Systea WIZ (wet chemical nutrient sensor) and Green Eyes NuLAB (wet chemical nutrient sensor).

Data Stream

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NO2+NO3

TSSeq (mg/L)

Abs360 (AU)

SAC254 (1/m)

Temp_C

ODO_prcnt_Sat

ODO_mg/L

SpCond_uS/cm

Sal_psu

Turbidity_FNU

Phycocyanin_RFU

Chlorophyll_RFU

Depth_m

Press_psi_a

No data to date

TriOS OPUS

The University of Louisiana at Lafayette (ULL) deploys the TriOS OPUS sensor in cooperation with the LO-SPAT project at Mosquito Bight in Eloi Bay, Chandeleur Sound, Louisiana.

The TriOS OPUS deployed by ULL measures nitrate as NO3 (mg/L), spectral attenuation coefficient at 254 nm (SAC254), and total suspended solids (TSSeq) by optical spectrum analysis. The OPUS nitrate detection range and environmental limitations vary with pathlength. The 10 mm pathlength OPUS was selected for the ULL deployment site in Chandeleur Sound, Louisiana.

Supporting links:

TriOS OPUS

OPUS nitrate manual

LO-SPAT real-time monitoring

No data to date

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NO2+NO3

Water Temperature

CDOM

Conductivity

Turbidity

Salinity

Sensor Depth

Dissolved Oxygen (Saturated)

Dissolved Oxygen

Chlorophyll

No data to date

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NO2+NO3

No data to date

The Systea WIZ nitrate sensor is deployed by the Sanibel-Captiva Conservation Foundation (SCCF) in Fort Myers, Florida; Mote Marine Lab (MML) in Sarasota, Florida; and, the Louisiana Universities Marine Consortium (LUMCON) in Chauvin, Louisiana. Texas A&M University (TAMU) in Freeport, Texas will deploy a WIZ nitrate sensor. The WIZ nitrate measures nitrate as N+N (μM).

The Systea WIZ phosphate sensor is deployed by the Grand Bay NERR in Moss Point, Mississippi. The WIZ phosphate measures phosphate as soluble reactive phosphate, SRP (μM).

The WIZ is capable of multi-channel measurements for the simultaneous detection of multiple nutrients. Thus far, all WIZ units deployed within the GOM Nutrient Sensor network are single-nutrient monitors. SCCF and Grand Bay NERR operate a WIZ with a 0.1 um pore size intake filter. Mote and LUMCON operate a WIZ with a 25 um pore size intake filter.

Supporting links:

Systea WIZ

SCCF water quality monitoring

Mote Marine Lab Chemical and Physical Ecology

LUMCON Environmental Monitoring

TAMU Oceanography

Grand Bay NERR System-Wide Monitoring Program (SWMP)

No data to date

The Green Eyes NuLAB nitrate and phosphate sensor is deployed for a demo test by the Mission-Aransas NERR / University of Texas Marine Science Institute (UT MSI) in Port Aransas, Texas. The NuLAB measures nitrate as N+N (μM) and phosphate as soluble reactive phosphate, SRP (μM).

The NuLAB deployed by UT MSI is a multi-channel nutrient monitor, simultaneously detecting nitrate and phosphate on separate analytical units.