But whether it is fast oxygen sensing, very high turbidity measurement, conductivity cells with integrated anti-fouling wiper, or multi-frequency fluorometer for phytoplankton classification, JFE Advantech has always worked closely with scientists to give them the necessary tools. A recent example is a specialized fluorometer and analysis technique that can identify certain specific algae species, such as Karenia mikimotoi and Chattonella antiqua, which are well known to cause harmful algal blooms (HABs).
Advancing HAB Measurements
HABs are common and significant worldwide problems, causing mass mortality of marine organisms, especially fish in aquaculture cages or shellfish hanging from rafts, and shellfish contamination can sometimes lead to human fatalities. In situ monitoring of cell abundance of harmful algae is an urgent necessity to reduce the damage caused by HABs.
A Relative Fluorescence Intensity graph. (Image credit: Swale)
Fluorometers have been widely used for quantification of phytoplankton in freshwater and marine environments for some time. Although using fluorescence generated by a single wavelength excitation in the blue region of the light spectrum can assess total phytoplankton biomass, it is not able to provide algal classification as performed by microscope counts; thus, the algal species composition in the water could not be understood.
Differentiating Species
The HAI instrument takes advantage of the Fluorescence spectral Shift Index (FSI) of two species, which is relatively high compared to other species (FSI is the ratio of fluorescence intensity at 690 nm to that at 670 nm in wavelength). Karenia mikimotoi (Dinophyceae) and Chattonella marina var. antiqua (Raphidophyceae) have been monitored daily for many years as the main species contributing to HAB disasters to aquaculture and fisheries in Japan, mostly by sampling water and microscope counts. In order to find an alternative monitoring technology to microscopic cell counting, the FSI method was developed and tested with Karenia mikimotoi and Chattonella marina var. antiqua. This new method is not only able to provide an estimate of the cell abundance of specific algae, but it also calculates its ratio in the algae population composition.
To find out more about the HAI sensor, visit: www.jfe-advantech.co.jp
This feature appeared in Environment, Coastal & Offshore (ECO) Magazine’s 2023 Winter edition Fisheries & Aquaculture, to read more access the magazine here.
