Analysis of Prochlorococcus marina, the smallest photosynthetic organism

Using a CytoSense the researchers from the Mediterranean Institute of Oceanography (MIO), Aix-Marseille University, successfully analyzed Prochlorococcus marina. With diameter of around 0.6 μm, this marine cyanobacterium is the smallest known photosynthetic organism. At the same time it is the most abundant photosynthetic organism on Earth. Quantitative analysis of Prochlorococcus marina with the CytoSense facilitates understanding of the role of this species in ocean ecosystems. 

Analysis of Microcystis, from single cells to colonies

The wide particle size range measured in the CytoSense enabled researchers to analyze Microcystis single cells and colonies present in Lake Taihu. Since September 2016 a CytoSense is applied to continuously monitor dynamics of this harmful cyanobacterium. It is a part of a large-scale program set up to protect water quality in Lake Taihu, drinking water source to over 30 million people. The CytoSense project is realized by the Taihu Basin Authority in partnership with the Dutch Ministry of Infrastructure and the Environment.

More information: Zhou et al. 2012 , CytoBuoy News

5 years (and counting) of river water quality monitoring

The CytoSense on the river Meuse analyses phytoplankton community hourly from March till November. It is an important part of the early warning system on this drinking water providing river. The project is led by the Dutch Ministry of Infrastructure and the Environment, in close collaboration with CytoBuoy and Thomas Rutten Projects.

More information: Real-time results, CytoBuoy News

Remotely controlled flow cytometry on a solar-powered buoy

The researchers from the Mediterranean Institute of Oceanography (MIO), Aix-Marseille University were the first to place a flow cytometer on a moored solar-powered buoy EOL (OVLFR). Throughout the 2 months deployment the CytoSub was controlled remotely. Resulting data was transferred via WIFI connection on a distance of 1.7 km. With this innovative approach, the researchers observed influence of wind, precipitation and phytoplankton community structure on the development of a spring bloom. Data collected every 2 hours showed phytoplankton community dynamics related to the daily cell cycle.

More information: Thyssen et al. 2014

The CytoSense during installation on the EOL buoyThe CytoSense during installation on the EOL buoyThe CytoSense during installation on the EOL buoyThe CytoSense during installation on the EOL buoyThe CytoSense during installation on the EOL buoyThe CytoSense during installation on the EOL buoySolar-powered EOL (Environnement Observable Littoral, CNRS-Mobilis) buoy. Photo credit: Denis et al. 2014
The CytoSense during installation on the EOL buoy
The CytoSense during installation on the EOL buoy
The CytoSense during installation on the EOL buoy
The CytoSense during installation on the EOL buoy
The CytoSense during installation on the EOL buoy
The CytoSense during installation on the EOL buoy
Solar-powered EOL (Environnement Observable Littoral, CNRS-Mobilis) buoy. Photo credit: Denis et al. 2014

Hourly monitoring of phytoplankton community dynamics in the Berre Lagoon (Marseille)

High frequency (hourly) monitoring of phytoplankton community in the largest brackish water lagoon in Mediterranean area was realized by means of a CytoSense by the researchers from MIO, Aix-Marseille University. Clusters revealed upon analysis of phytoplankton community were shown to be functional response groups, both regarding the daily variations as well as sudden environmental changes. The measurements showed dynamics of Akashiwo sanguinea throughout a strong wind episode (mistral). This species is known to form harmful algal blooms (HAB).

More information: Dugenne et al. 2014Dugenne et al. 2015 

Analysis of fresh, untreated phytoplankton during ship cruises

With a CytoSense on board the researchers from Université du Littoral Côte d'Opale (CNRS-LOG) observed abrupt changes in composition and in abundance of Synechococcus spp., picoeukaryotes (< 2 μm), haploid and diploid Phaeocystis globosa, Cryptophytes, Diatoms and Coccolitophores. During another cruise, the CytoSense detected on average 10x more Cryptophytes in comparison with microscopic quantification which required sample fixation. 

More information: Bonato et al. 2015, Bonato et al. 2016

Fighting a Harmful Algal Bloom in the Netherlands

At the start of august 2012, a dangerously high concentration of the dinoflagellate Alexandrium Ostenfeldii was found within a creek near Ouwerkerk, Zeeland. This species is known to produce very toxic substances (saxitoxine among others), and with concentrations of millions of cells per liter this could pose a threat to humans and wildlife. Luckily these algae could be isolated in time. But how to get rid of them?

In a cooperative effort between Rijkswaterstaat, Arcadis, the University of Amsterdam and the local authorities a newly developed method was tested. By adding low concentrations of hydrogen peroxide the bloom could be destroyed. The CytoSense instrument owned by Rijkswaterstaat was used for analyzing the effects of the treatment. By closely monitoring the concentrations and activity of the species using the Cytosense, the effects of the treatment could be tracked in real time. The results of this analysis were used to tune the exact amounts of H2O2 to be added. Within two hours after the addition of the peroxide the photosynthetic capacity was dimished by 97%, and after two days the concentrations of Alexandrium Ostenfeldii was brought back to only 1% of its original value, making the water fit for mixing with other surface waters again. Since peroxide breaks down into water and oxygen, it poses no long-term threats to the ecosystem.

Phytoplankton community changed by personal care products

The CytoSense at the Swiss Federal Institute of Aquatic Science and Technology provided interesting data on the influence of micropollutants present in common pharmaceuticals and personal care products on the phytoplankton diversity and biomass.

More information: Pomati et al. 2017 

Fungi monitoring in filamentous bioprocess

The researchers from TU Wien monitored spore germination real-time by means of a CytoSense with accuracy >95%. Analysis of stained Penicillium chrysogenum spore with a CytoSense revealed activation of their metabolic activity and simultaneous change in their size and surface character. This flow cytometric analysis was possible despite the presence of other particles common for complex media used in filamentous bioprocess.

More information: Ehrgartner et al. 2016aEhrgartner et al. 2016b

Scatterplot obtained with a CytoSense showing clear discrimination of the Prochlorococcus and Synechococcus. Photo credit: Gerald Grégori
Monitoring station on Lake Taihu, China, where a CytoSense is used to monitor Microcystis.Setting up the CytoSense in the monitoring station on Lake Taihu, China.
Monitoring station on Lake Taihu, China, where a CytoSense is used to monitor Microcystis.
Setting up the CytoSense in the monitoring station on Lake Taihu, China.
Monitoring station on river Meuse where since 2013 a CytoSense is used for hourly monitoring of phytoplankton community. Photo credit: Rijkswaterstaat
Real-time Monitoring in Ouwerkerk using the Cytosense (picture: Bram van Weerdenburg)
The Alexandrium Ostenfeldii before the treatment (left) and after (right) Pictures were made using the CytoSense