Early detection of harmful algal blooms

Bloom of toxic algae (Alexandrium pacificum) in Nydia Bay, Pelorus Sound. © Lincoln MacKenzie, Cawthron Institute

We are trialling two innovative technologies to detect and monitor harmful algal blooms in coastal waters. 

Project leader: Dr Lincoln Mackenzie, Cawthron

Duration: July 2017 – June 2019
Budget: $300,000 
Status: Ongoing 

Harmful algal blooms are natural phenomena that sometimes occur in coastal ecosystems. They can have detrimental effects on human health, seafood harvesting and aquaculture businesses.  

We are trialling two new complementary technologies for detecting and monitoring algal blooms. Our aim is to apply new technologies and develop simple, cost-effective and sensitive tests that can be used by public health agencies, the aquaculture industry and communities in Aotearoa New Zealand. 

The first method detects and quantifies algal DNA in the water. In mid-2018, we field trialled this method when a major bloom of toxic algae (Alexandrium pacificum) occurred in Pelorus Sound. We were able to estimate the amount of the algae present from multiple locations in the area within 90 minutes of collecting samples. The method was sensitive, simple and practical, and we are now working to improve estimates of the quantities of algae present.  

The second method we are evaluating uses a robotic submersible microscope developed by an American company (McLane Research Laboratories). The device, an Imaging FlowCytoBot, can automatically identify and count microscopic algal cells underwater. Before we can start using it, we need to train the software to recognise local species. For this work, we are collaborating with the aquaculture industry and an international expert who has experience with this instrument.  

Our aim is to use these technologies as an early warning system so that impacts on shellfish and finfish harvesting are minimised, and risks of recall of contaminated products are reduced.  

Journal articles

Ruvindy R, Bolch CJ, MacKenzie L, Smith KF & Murray SA (2018).  qPCR assays for the detection and quantification of multiple paralytic shellfish toxin-producing species of Alexandrium. Frontiers in Microbiology 9:3153 DOI: 10.3389/fmicb.2018.03153

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