Landcare Research links Wanaka snot and Seattle slime; wins $1 million study grant

Dr Phil Novis of Landcare research holds a sample of lake snot.
Joseph Johnson

Dr Phil Novis of Landcare research holds a sample of lake snot.

Lake snot, lake snow, lake slime: anyway you say it, it's the same stuff and Landcare Research scientists have just won $1 million to do more research on it.

The Ministry of Business Innovation and Employment's funding announcement for a Lake Snot Tool Box on September 13 came on top of the release of an Otago Regional Council-commissioned study by Landcare Research scientist Dr Phil Novis and colleagues on the DNA of lake snot.

Novis et al found the genetic source of Lindavia intermedia (the algae responsible for creating the lake snot mucous) is highly likely to be from outside New Zealand, though it is not clear how it got here.

Lake snot in Lake Wanaka.

Lake snot in Lake Wanaka.

It backs up what Otago University Scientist Marc Schallenberg reported in June 2016: the floating mucous in Lake Wanaka was similar to an overseas slime in Lake Youngs, near the Washington, US city of Seattle. 

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Otago Regional Council technical committee chairman Andrew Noone is keen for a multi-agency national project that can work on potential solutions and minimise the effects of the mucous.

Lake Wanaka has been invaded by an alien organism responsible for lake snot.
Marjorie Cook

Lake Wanaka has been invaded by an alien organism responsible for lake snot.

He was unaware of Landcare Research's successful application to the MBIE's 2017 Endeavour Round until contacted by Stuff.

"I am ecstatic for the community. This has been hovering around for quite some time, [people asking] "what is it, what do we do". Now our stars are lining up. There has been frustration in the community but now we are starting to get some traction," Noone said.

Lake snot causes problems with recreation and water supply in lakes in New Zealand and around the world. It fouls boat motors, clogs water filters, sticks to skin and clings to fishing line.

White flocs on the surface of Lake Wanaka are a sign of heavy snot infestation.

White flocs on the surface of Lake Wanaka are a sign of heavy snot infestation.

Filtering the organism could cost councils and ratepayers millions of dollars.

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The council commissioned Landcare Research to do genetic tests of lake snow samples after a multi-agency expert workshop in Wanaka in 2016.

Landcare Research found that specimens from Lake Youngs and all NZ lakes were identical in more than one respect.

Noone said now more was known about the genetics of lake snot, a more intensive research programme could get under way to understand the diatom and work towards potential solutions.

 "We know that lake snow has been causing ongoing concerns across New Zealand, and particularly that there are frustrations about this in our own backyard in affected areas in the Otago region." 

"Whilst lake snow is clearly a nuisance to lake users, I want to be very clear that water quality in our lakes is excellent and this species is not harmful to human health," Noone said.

The council has been liaising with key stakeholders and the Ministry of Primary Industry on the Landcare Research report findings.

"Our council feels strongly that this is an issue that needs to be tackled nationally with our key partners," he said.

Dunstan constituency councillor Ella Lawton said Landcare Research's report was "pretty good" and "as clear as you can get for science". 

The report threw up many interesting issues, including why Lindavia intermedia could not always been found when people went out to collect samples, likely because of variable conditions.

"It has highlighted again, it is quite fickle . . . The really important thing that we need to find out is what causes it to make the mucous. It can live in the lake without creating the mucous . . . If it is going to disappear should councils spend a lot of money on it?," Lawton said.

Another interesting issue was the value of lake snot for fish species, she said.

The report prepared for the regional council was the first in a series of studies on lake snow, including its origins, dominance, effective sampling and monitoring, methods to stop the spread and whether it can be managed.

The regional council will present the report and take questions at a public meeting at the Lake Wanaka Centre on October 4 from 7pm.


The Ministry of Business Innovation and Employment announced on September 13 it had allocated $1 million from its 2017 Endeavour Round to Landcare Research's new project, The Lake Snow Tool Box.

The project is one of 68 new science research projects receiving about $250 million over five years.

The Lake Snow Tool Box summary describes Lindavia intermedia as "a threat to tourism, municipal water supply, irrigation and hydroelectricity infrastructure, and to the recreational and cultural values of some of NZ's most pristine lakes".

Like didymo, it threatened New Zealand's highest-quality freshwater ecosystems. Scientists, councils and other stakeholders had agreed eradication was impossible.

To reduce or eliminate slime production, a much better understanding of its ecology, was needed. This required new tools to quantify both the alga and the slime it produces. 

Landcare Research wants to create low-cost, mass produced sensors that specifically detect lake snow 'threads' and exclude other types of particles.

The project would benefit organisations and communities vulnerable to millions of dollars in annual lake snow management costs. It would also assist iwi and iwi partners as guardians and developers of freshwater resources. 

 - Stuff


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