Satellite monitor of NZ’s algal blooms

An Alexandra-based company has joined forces with Nasa on an Earth-observing satellite mission to detect some of Earth’s most microscopic producers of harmful or potential killer toxins.

Regional research institute Xerra Earth Observation Institute was accepted as an early adopter to the space agency’s Plankton, Aerosol, Cloud and ocean Ecosystem (Pace) mission last month.

The purpose of the Pace mission is to assess ocean and lake health by measuring phytoplankton — the tiny plants and algae that sustain the marine food chain.

It will also record key atmospheric variables associated with air quality and Earth’s climate.

Xerra scientist Moritz Lehmann said Xerra’s inclusion in the programme offered New Zealand scientists the opportunity to collaborate with scientists across the globe in the application of the satellite data to advance research of global ocean colour, biogeochemistry, and ecology, as well as carbon cycle, aerosols, and clouds.

"It is a bit of an unusual approach for Nasa to design a mission in that it is designed for the end user."

Dr Lehmann said his work, in conjunction with the University of Waikato and the Nelson-based Cawthron Institute, would involve harmful algal bloom monitoring and detection in New Zealand inland and coastal waters.

"It’s a mission that will be able tell harmful algal blooms from non-harmful algal blooms."

That meant utilising high-tech satellites that would circumnavigate the globe every two days.

The technology includes an ocean colour instrument — an optical spectrometer capable of measuring the colour of bodies of water from ultraviolet to shortwave infrared.

That technology was superior to a video camera, which only recorded colour made up of red, green, and blue pixels, he said.

"It measures light at many nuances across the spectrum."

Algal blooms can be toxic to humans and animals, and New Zealand coastal waters and large lakes are increasingly threatened by such blooms, Dr Lehmann said.

Alive or dead, the blooms were a problem.

While some could be short-lived, others could be persistent, and when cells died out, that created other issues, he said.

"They die and sink to the bottom of the lake, and their decomposition process takes oxygen from the water."

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