Incorporating molecular tools into routine HAB monitoring programs: Using qPCR to track invasive Prymnesium

Microscopy, a staple of monitoring programs for tracking the occurrence and abundance of harmful algal bloom (HAB) species, is time consuming and often characterized by high uncertainty. Alternate methods that allow rapid and accurate assessment of presence and abundance of HAB species are needed. For many HAB species, such as the toxigenic haptophyte, Prymnesium parvum, molecular methods including quantitative real-time PCR (qPCR) have been developed with the suggestion that they should be useful for monitoring programs. However, this suggestion rarely has been put into action. In this study, we modified a recently developed method for detecting P. parvum using qPCR and tested its efficacy as an alternative to microscopy for P. parvum detection and enumeration in a long-term monitoring program in a recently invaded subtropical US reservoir. Abundance estimates of P. parvum were similar for both methods, but we detected P. parvum at multiple sites using qPCR where it previously had gone undetected by microscopy. Using qPCR, we substantially reduced processing time, increased detection limit and reduced error in P. parvum abundance estimates compared to microscopy. Thus, qPCR is an effective tool for detecting and monitoring P. parvum, particularly at pre-bloom densities, and should likewise prove useful in monitoring programs for the other HAB species for which qPCR methods have been developed. (C) 2011 Elsevier B.V. All rights reserved.