Aquatic Science Applications

CytoBuoy and Aquatic Science

Aquatic science is the main target field for the development of our products, and has been since 1986. Currently the CytoBuoy flow cytometers have the largest range of deployment options, the largest range of particle sizes and concentrations and the largest range of analysis options available. A wide range of aquatic research and monitoring is done with our instruments.

Challenges

The two main challenges of this field are:

  • the enormous range in particle types, sizes, their concentrations and physiological states. 
  • dynamic ecosystems requiring sampling at critical scales: the temporal and/or spatial scales at which data must be collected in order to resolve patterns and processes (including early warning).

Briefly those two challenges require an instrument that combines a high level of information content and a high frequency in sampling times and/or space (coverage).

High frequency, high data quality

Whereas traditional flow cytometers analyze thousands of cells per second acquiring only a few fluorescence and light scattering numbers per cell, the recording of full photos at similar count rates would yield an unmanageable data flow. The CytoBuoy instruments use silico-imaging (pulse shapes) as basic data format: data-extensive but highly informative optical fingerprints obtained by fluid driven laser scanning of individual particles. Libraries of these fingerprints allow the automatic classification and enumeration of groups and species from large data sets as well as online warning for target (HAB) species.

Size range

The size range of the CytoSense is exceptional. Thanks to years of development, picoplankton (very small) as well as big diatoms, chains and filaments etc can be detected with the same machine. The maximum diameter 800 um and length may be several mm, while particles of sub-micron length can still be detected. This also solves the problem of instrument clogging with running field samples through the instrument:  fractionating or filtering the sample is not required, neither concentrating. The volumetric sample dosing allows the direct reading of concentrations whereas the automatic flow rate adjustment assures optimum data quality for sediment rich and/or eutroph to oligotroph conditions.

A world of applications

Thanks to these qualities the applications in the field of aquatic science span as wide as screening of phytoplankton cultures, natural samples, detection of rare species, population dynamics research, general phytoplankton monitoring, assessment of biodiversity, bio-indicators, HAB's (harmful algal blooms), grazing, (micro)zooplankton, protection of aquaculture, bathing water, resource water, lake restoration, alarm for herbicides, invasive species control and bio-effect monitoring, marine optics and lake or sea truth tables for remote sensing. This versatility is acknowledges by the market: our instruments are in operation all over the world.

Several partners in the Dymaphy project - all aquatic scientists - on a CytoSense calibration meeting in Boulogne

Length estimation with the CytoSense

The CytoSense can make an exceptionally good estimation of the length of particles over a very big size range. In this graph the length estimated by the CytoSense (in um) is plotted against the length of the same particles in a picture taken with the Image in Flow module. The very strong correlation shows that the estimate is near perfect. This allows for length analysis of 1000+ particles per second!

A water flea - extremely large! - imaged. Here the advantage of the pulse data is clear: we can see two phytoplankton cells that are eaten by the creature, but still fluorescent inside its body.