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. 

Help Shape a High- Frequency Plankton Observation Guide

To support harmonisation across the community, Dr. Veronique Creach (Cefas) is developing a Terms of Reference (TOR) within the ICES Working Group on Phytoplankton and Microbial Ecology (WGPME): “Create a guide for determining consistent plankton observations at high frequency.”

High-frequency flow cytometry and imaging are increasingly used to characterise phytoplankton diversity, including community cell-size structure. This approach aligns with the GOOS-edited (2025) Essential Ocean Variable Specification Sheet and supports higher-order products such as Phytoplankton Functional Types. As autonomous, high-sampling deployments expand, shared best practices for
collection, measurement, and analysis are essential.

To support harmonisation across the community, we are developing a Terms of Reference (TOR) within the ICES Working Group on Phytoplankton and Microbial Ecology (WGPME): “Create a guide for determining consistent plankton observations at high frequency.”

Who we’re looking for: CytoBuoy users (any platform or configuration).
What to share: sampling workflows, calibration/QA approaches, processing pipelines, metadata practices, and lessons learned from autonomous/high-frequency deployments.
Why participate: help establish consistent methods and improve
comparability across datasets and regions.

If you use a CytoBuoy instrument and would like to contribute, please contact Dr Veronique Creach (veronique.creach@cefas.gov.uk) or Nicole Poulton (npoulton@bigelow.org). A brief note describing your instrument configuration and use case is enough to get started.