In Situ Ultraviolet Spectrophotometer

MBARI's ISUS with Anti-fouling Filter

MBARI’s ISUS with Anti-fouling Filter

The ISUS is a sensor used to measure concentrations of dissolved chemicals directly from their Ultraviolet Absorption Spectrum (Johnson and Coletti, 2002). A variety of chemicals absorb light in the UV and each of these chemicals has a unique absorption spectrum. We can determine the concentration of these chemicals directly, with no chemical manipulation, by measuring the absorption spectrum of seawater in the UV and then deconvolving the spectra to yield the concentration of each component. The ISUS is now commercially available from Satlantic, Inc.

ISUS has been used to determine nitrate concentrations while deployed on CTD/Rosette profilers, undulating towed vehicles such as a SeaSoar or SeaSciences Acrobat, and on deep-sea moorings. It has also been used to measure sulfide flux from cold seeps in Monterey Bay while deployed on the Remotely Operated Vehicle Ventana.

ISUS UV Spectra Plot

ISUS UV Spectra Plot

Real-time nitrate data from an ISUS deployed on the MBARI M1 mooring is also available. There are two processors running for this data: one written by Luke Coletti (CGI application ) that includes interactive fitting of nitrate and can also be used to compare nitrate concentrations to other properties such as temperature, fluorescence and CO2; and one written by Ken Johnson (Visual Basic script) that compares the real-time data to historical observations in Monterey Bay.

To learn more about ISUS read our paper in Deep-Sea Research and check Luke Coletti’s home page for several posters that have been written about ISUS. To learn about applications of ISUS to studies of phytoplankton primary production, we have another paper in Deep-Sea Research.

ISUS was developed with support from the National Science Foundation and from MBARI.

Team

Technology

Solving challenges
Taking the laboratory into the ocean
Environmental Sample Processor (ESP)
In Situ Ultraviolet Spectrophotometer
Midwater Respirometer System
Mobile flow cytometer
Enabling targeted sampling
Automated Video Event Detection
Environmental Sample Processor (ESP)
Gulper autonomous underwater vehicle
Mobile flow cytometer
Wave Glider-based communications hotspot
Advancing a persistent presence
Aerostat hotspot
Benthic event detectors
Benthic rover
Fault Prognostication
Long-range autonomous underwater vehicle Tethys
MARS hydrophone for passive acoustic monitoring
Monterey Ocean-Bottom Broadband Seismometer
Shark Café camera
Vehicle Persistence
Wave Glider-based communications hotspot
Emerging and current tools
Communications
Aerostat hotspot
Wave Glider-based communications hotspot
Data management
Oceanographic Decision Support System
Spatial Temporal Oceanographic Query System (STOQS) Data
Video Annotation and Reference System
Instruments
Apex profiling floats
Benthic event detectors
Deep particle image velocimetry
Environmental Sample Processor (ESP)
Persistent presence—2G ESP
How does the 2G ESP work?
Arrays on the 2G ESP
Printing probe arrays
Expeditions and deployments
In Situ Ultraviolet Spectrophotometer
Investigations of imaging for midwater autonomous platforms
Lagrangian sediment traps
Midwater Respirometer System
Mobile flow cytometer
SeeStar Imaging System
Shark Café camera
Smart underwater connector
Power
Wave-Power Buoy
Vehicle technology
Benthic Rover
Gulper autonomous underwater vehicle
Imaging autonomous underwater vehicle
Seafloor mapping AUV
Long-range autonomous underwater vehicle Tethys
Mini remotely operated vehicle
ROV Doc Ricketts
ROV Ventana
Video
Automated Video Event Detection
Deep learning
Video Annotation and Reference System
Technology publications
Technology transfer