Scottish Marine and Freshwater Science Vol 8 No 24

A small number of phytoplankton species have the ability to produce algal toxins which can accumulate in filter feeding bivalves such as oysters, scallops and mussels. The bioaccumulation of algal toxins can potentially cause serious health issues to shellfish consumers. Countries with a shellfish aquaculture industry (such as Scotland) have set up for their classified production areas a phytoplankton monitoring programme as part of their legal obligations (EC 854/2004 and amendments). This involves the regular collection of water samples to assess the phytoplankton community using light microscopy, with a particular emphasis on the toxin producing species. However, this technique lacks the ability to identify some key phytoplankton to a species level (e.g. Pseudo-nitzschia sp., Alexandrium sp.), which is critical to appropriately assess the potential toxicity of a phytoplankton bloom event. The objective of this project was to evaluate a microarray technique which was developed during the MIDTAL project (Microarrays For The Detection of Toxic Algae: http://www.midtal.com/) to identify phytoplankton to species level. Microarrays are modified glass supports on which are printed RNA probes that are species-specific. Each targeted phytoplankton species is defined by a set of probes that are statistically unique to each one. For the purpose of this project, water samples were collected offshore from Stonehaven (East coast of Scotland) over a two years period (starting in 2015) and processed using the microarray to assess its specificity and sensitivity in relation to the identification and potential semi-quantification of toxic strains of phytoplankton.