Monitoring the Ocean in Color with MatrixFlu

Earthzine2017 Monthly Focus Topic, Original

Dr. Oliver Zielinski of University of Oldenburg discusses the MatrixFlu sensor in a question and answer session with IEEE Earthzine.

Dr. Oliver Zielinski

A group of “Oceans of Tomorrow” projects funded by the European Commission include NeXOS, to develop next generation web-enabled sensors for the monitoring of a changing ocean. One of those sensors, MatrixFlu, is described as a compact optical multifunctional sensor that uses matrix fluorescence to scan water samples for dissolved components. An ultraviolet version targets dissolved organic matter and polycyclic aromatic hydrocarbons, and a visible version measures turbidity.
Dr. Oliver Zielinski is a professor for marine sensor systems and director of University of Oldenburg’s Institute for Chemistry and Biology of the Marine Environment in Oldenburg, Germany. Zielinski’s research covers marine optics and marine physics, with a focus on coastal systems and sensors.
Zielinski discussed the MatrixFlu sensor in a question and answer session with IEEE Earthzine.
Q: Describe the capabilities of the sensor and how their development fits with the goals of the NeXOS initiative.
A: The MatrixFlu is a multiwavelength, multiparameter fluorometric sensor. That means it uses light at different wavelengths to excite target substances in the water that will then exhibit the emission of light at a different wavelength detected by the sensor again. These targeted substances encompass key ecosystem parameters like chlorophyll a (a pigment prominent in all algae), oil in water and colored dissolved organic matter (CDOM, from biomass degradation).
What is unique about the MatrixFlu is its compact and flexible design. The different optical combinations from excitation and emission wavelengths form a matrix that holds the potential to even detect so far unexpected substances in a water body. This feature is in line with the multi-purpose objectives of the NeXOS project. Other goals of NeXOS, like open standards to ease integration and compactness or power efficiency, are also embedded into the MatrixFlu. Thus, it is possible to integrate the same sensor into different platforms (like autonomous underwater vehicles, moorings or underway systems) with a minimum effort for integration.
Q: What has been your personal involvement in the project?
A: The MatrixFlu concept is part of my vision to make modern laboratory excitation-emission-matrix-spectroscopy (known as EEMs) available in situ, that means as part of ocean observatories. Therefore, I drafted the MatrixFlu approach together with the project partner TriOS optical sensors (Germany) as part of the NeXOS proposal. Within the project, I am responsible for the lead of the whole work package 5, focused on optical sensors, and of course with a specific interest and contribution to the MatrixFlu sensor.

The MatrixFlu sensor. Image Credit: Oliver Zielinski

Q: What is the future of this technology and what benefits will the scientific community be seeing from this endeavor?
A: Currently there are two versions of MatrixFlu, one for the ultraviolet wavelengths, targeting at oil and CDOM components, and one for the visible domain, addressing different chlorophyll pigments. Both of them are of high benefit to the scientific community already, since they enable multi-parameter investigation in the size (and at the cost of) a single parameter instrument. Linking both sensors and exploiting their spectral coverage will be one of the next tasks. This involves field applications and validation exercises, like they are currently ongoing within NeXOS. Integrating the MatrixFlu in many platforms, including Argo floats and gliders, will push the insight we can get on complex biogeochemical interactions to a new limit.
For more information, see “A New Generation of Optical Systems For Ocean Monitoring.” Uses for MatrixFlu include detecting and quantifying hydrocarbon pollutants associated with ship traffic and sewage runoff. The sensor has been commercialized by TriOS in Germany.
This is part of a series of NeXOS articles. The others are below:

This article was funded in part by the NeXOS project by Grant Agreement No. 614102 under the call FP7-OCEAN-2013.2 from the European Commission.

Jeff Kart is managing editor of IEEE Earthzine.