Development of an `early warning system' for harmful algal blooms using solid-phase adsorption toxin tracking (SPATT)

Solid-phase adsorption toxin tracking (SPATT) is founded on the observation that when low levels of toxic dinoflagellates are present in the water column significant amounts of toxins are dissolved in seawater. Previous researchers demonstrated a lag between detection of dissolved toxins adsorbed onto porous synthetic resin, phytoplankton peak cell densities and highest toxin concentrations in shellfish. Here we report on optimised protocols (resin type, type and volume of solvent extraction) for SPATT and subsequent field trials at Loch Ewe (Scotland) which used SPATT in the form of suspended SEPABEADS® SP700 held within a mesh sachet. Sachets were suspended at 7 m and retrieved weekly with new ones put in and water samples for phytoplankton collected. Phytoplankton cells were identified using conventional light microscopy. The resin from the mesh bags was extracted and analysed for lipophilic toxins using liquid chromatography with mass spectrometry (LC-MS). Results demonstrate the potential of SPATT to provide time integrated sampling to monitor the occurrence of toxic events.