A Biosensor Monitoring Approach for Toxic Algae: Field Validation of Selected Probes for Benthic Toxic Species Attached to Macroalgae at Boa Vista Cape Verde Islands

Toxic benthic dinoflagellates are predicted to increase with increased temperature stratification and eutrophication. Total rRNA was extracted from cells washed off macroalgae collected at low tide from selected sites on north and western coasts of Boa Vista Cape Verde. The rRNA was tested for the presence of certain toxic dinoflagellates using a molecular barcode to each target species and detected with electrochemical measurement methods in order to establish which macroalga could harbour benthic dinoflagellates. We provide a first rough indication of their density and distribution and probe sensitivity. Toxic planktonic dinoflagellates were also collected from the washes of the macroalgae, indicating that they had likely settled out of the plankton and were trapped on the surface and within the branches of macroalgae. Notably certain benthic dinoflagellates were also found to be abundant in the two plankton samples taken. Electrochemical detection with a biosensor is an alternative cheaper and easier to use method for the detection of toxic algae. A northward progression of emergent toxic tropical species has been now detected with our methods from Cape Verde to the northern Iberian Peninsula because climate change has modified ocean temperatures to enable their survival.