Israelis Find the Secret to Killing Deadly Algae Blooms

Toxic blankets of cyanobacteria and dinoflagellates are choking the world's seas and lakes. One company, BlueGreen Water Technologies, has a solution and it’s affordable and environmental to boot

Ruth Schuster
Ruth Schuster
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Blooms in Lake Erie
Green is the worst algae bloom Lake Erie has experienced in decades: Image captured by the Landsat-5 satellite.Credit: Jesse Allen and Robert Simmon / NASA Earth Observatory
Ruth Schuster
Ruth Schuster

Four billion years ago, something in the primordial ooze came alive. The first creatures may have been capable of photosynthesis: harvesting solar energy to create their food. In other words, the first organisms may have been primeval cyanobacteria.

Cyanobacteria are among the most successful organisms ever to have lived, given that they’re still here. In fact, as the organism that usually crowns itself the most successful of all sends the planet reeling out of balance, vast “algae blooms” consisting of cyanobacteria and dinoflagellates are choking our waters, creating vast “dead zones” and making us sick. Given our trajectory, cyanobacteria could be the last beings to survive on Earth.

Their blooms can be so enormous they can be seen from outer space. And one Israeli startup can do a unique thing: kill them, claims Dr. Moshe Harel, chief technology officer and BlueGreen cofounder. Kill them effectively, affordably and “greenly.”

Founded in 2014 in Israel, BlueGreen has two patented “Lake Guard” formulations, subsidiaries in the U.S. and China, and since commencing commercial operations in 2017, it has many a cyanobacterial scalp on its belt.

One is Ohio’s Lake Chippewa, which had been considered untreatable. Every year the bloom got worse, fed by spores from the prior season. Also, during heavy rains, cyanobacterial scum would be flushed downstream, infecting other watersheds. BlueGreen treated Chippewa in early August 2019, deploying its granules in less than an hour. Within 24 hours the bloom was history and the micro-organismal balance was shifting back towards natural. The company is also working in water bodies in Florida, South Africa, Israel and much more.

In Yixing, China, fishponds and waterways by Lake Tai had become badly contaminated. It took two days to beat the bloom and two weeks to restore normal phytoplankton balance, the company says. Further work in China is on ice right now because of the coronavirus outbreak. In Russia, the company treated the perpetually-plagued Park Pobedi lake in Tatarstan in October 2018. A year later it was still bloom-free. It’s also working on drinking water sources in South Africa, where the heavily contaminated Roodeplaat Dam is being remediated. In Israel BlueGreen works extensively with the national water company Mekorot.

The bright green is cyanobacterial blooms off Fiji, seen from outer space
The bright green is cyanobacterial blooms off Fiji, seen from outer spaceCredit: Norman Kuring / NASA Earth Observatory

“We can treat any water body, any size, any shape, depending on the budget,” says Harel. The treatment may cause grayish foam to form on the lake surface: it’s a sign that the cyanobacteria are dying, and will pass in a week or two.

Tickled pink

The benefit to everyone from mankind to fishkind of beating back blooms would be immense. Conditions have combined in favor of these ancient microbes: global warming (they love it), sewage disposal into waterways and seas (they eat it), farming that culminates in fertilizer and waste entering local waterways, lakes and seas (they eat that, too).

Happiest in spring and summer, some cyanobacteria are cold-resistant to begin with, indicating that the family in general have the propensity to survive winters too. Feeding on our waste and ecstatic in the warming waters, cyanobacteria are gaining domination in watery ecosystems.

Why are blooms such a problem? One: over billions of years of evolution, cyanobacteria evolved toxic waste that is dangerous to everybody that’s not them, causing dermal, neural and hepatic problems and they may even be associated with Alzheimer’s.

Two: below the cyanobacterial mat, it’s too dark for algae to photosynthesize, and atmospheric oxygen can’t mix into the water column. The starved algae die and the fish suffocate. Thus dead zones are born.

Duck swimming in cyanobacteria infected Lake Tai in China
Duck swimming in cyanobacteria infected Lake Tai in ChinaCredit: ASSOCIATED PRESS

Three: the cyanobacterial biomass clogs pipes, and you can’t just pick up and move a pipeline, BlueGreen’s chief marketing officer, Maayan Nave, says.

Four: blooms have been unsolvable, as the world’s waters warm, and because we keep feeding them with pollution.

If you kill everything

Until now the only solution for an algal bloom has been to wait for winter and hope the microscopic bastards freeze to death and don’t become cold-resistant. “We call it cyanobacterial infection. You have to cure the infection,” Harel says of their novel microbiological approach.

BlueGreen is advised by Prof. Aaron Kaplan of Hebrew University, a world expert on phytoplankton, and Dr. Waleed Nasser, an expert on infectious disease. The company makes two products, Lake Guard Oxy and Lake Guard Blue, based on hydrogen peroxide and copper sulfate respectively. Both have been approved for use in drinking water – the gold standard - by the U.S. Environmental Protection Agency. Oxy leaves no environmental trace whatsoever; Blue causes some copper to sink to the lake bottom, but the amount is small and it isn’t toxic, the company says.

The trick is to encapsulate the cyano-terminator in granules that float together with the cyanobacteria, slowly releasing the agent of doom, hydrogen peroxide.

Coccolithophore bloom off Brittany
Coccolithophore bloom off Brittany, seen from outer spaceCredit: Jacques Descloitres, MODIS Rapid Response Team, NASA/GSFC

Hydrogen peroxide causes the cyanobacteria to experience oxidative stress. That can harm any microorganism, including good bacteria and algae. But cyanobacteria are peculiarly vulnerable.

Hit a few times with hydrogen peroxide, the stress is repeated and the cyanobacteria enter a process called programmed cell death, Kaplan says. The first oxidative stress plays havoc with their proteins. It’s better population-wise for the cell to die and not produce new generations that would be defective.

Now: BlueGreen’s slow-release granules float with the bloom for hours, blown hither and yon by the wind. As the microbes die, a chain reaction ensues: dying cyanobacteria emit a molecule that sensitizes naïve cyanobacteria to hydrogen peroxide. The result is spreading circles of programmed cell death. C’est tout.

It also means they can use tiny amounts, well below the lethal dose compared with single massive application, Kaplan says.

But much depends on the size of the water body and the degree of its infestation.

In the South African project currently in execution, for example, BlueGreen has to apply several tons of their Oxy solution into selected parts of the Roodeplaat Lake because of intense cyanobacterial infection.

Moshe Harel, wearing hat, and Maayan Nave at the dam of heavily infected Roodeplaat Lake in South Africa: The green scum is an algae bloom
Moshe Harel, wearing hat, and Maayan Nave at the dam of heavily infected Roodeplaat Lake in South Africa: The green scum is an algae bloomCredit: Francois Flair

“Roodeplaat is a concrete arch dam with an approximate surface area of 439 hectares, or 4.4 square kilometers,” Harel tells Haaretz. “It was constructed in 1956 as an irrigation dam but [the lake] developed into an important water source for the northern areas of Pretoria. Soon after its creation, this dam gained popularity for recreational purposes and to this day is regarded as the best rowing venue in South Africa. But due to the influx of sewage treatment effluent, the conditions of the dam are highly eutrophic and often result in algal, cyanobacterial and hyacinth blooms.”

Due to an population growth and the prevalence of drought, South Africa’s renewable water resources per capita is at an all-time low. Pressure is mounting on the demand for fresh water resources that are suitable for human consumption. Less than an estimated 50% of South African households have piped water access to their homes and many in impoverished communities need to share a communal tap. They need what water they have.

Another advantage of the technique is that one doesn’t have to float in a boat batting away mosquitoes and spraying toxic compounds all over the algae bloom, a hopeless, inefficient and costly proposition if the bloom is any kind of respectable size. Moreover, if you rely on spraying the whole bloom surface, you’re going to miss a lot. The problem will inevitably recur.

In appropriate cases they use Blue, which contains copper sulfate, which damages the cyanobacteria’s proteins. The germ again winds up in the production of active oxygen compounds, causing oxidative stress. Where possible the company uses Oxy because it is more direct, Kaplan says.

Angles of attack

BlueGreen is far from the only group to focus on the demon blooms, the thing is, other solutions haven’t worked so far. Or at least, they didn’t work well, or weren’t efficient, or were environmentally destructive.

“I think hundreds of millions of dollars went into researching with zero result,” Harel says. “Reducing nutrients, monitoring, prediction, consequences – zero results. In any case, prediction can’t help if you can’t treat the infection.”

Futile attempts include collecting the scum from the surface, which resulted in more scum, Nave describes; there were attempts to dismay the cyanobacteria using aluminum, but it was expensive and the main ones being dismayed were benthic dwellers on the lake bottom, who found themselves living in metallic sludge. Nobody wants that.

Red tide
Red tideCredit: Marufish

Killing by ultrasound sounds intriguing but has been another flop in the field. “Generally laboratory studies are OK but large scale field trials are the problem,” Prof. Timothy Mason of Coventry University told Haaretz.

Asked how research on low-energy ultrasound for algaecide has been progressing, Dr. Miquel Lurling of the Environmental Sciences Group at Wageningen University was clearer: it’s “pure nonsense,” he says.

“The energy used is far too low to cause [the cyanobacteria] any damage and if one would use more energy, everything in close vicinity of the power beam [would] be killed,” Lurling told Haaretz. Having tested it, the results “as well as the physical laws in our universe make that we have concluded that there is no music in fighting cyanobacteria with ultrasound.” They won’t be putting a penny more into research in that direction, he added.

Soon BlueGreen will start treating blooms in the oceans, too, Harel says. Kaplan agrees that the technique should work the same with dinoflagellates, the cause of red tides.

Like any infection, the earlier you catch it, the easier and cheaper it is to treat, Harel says. One treatment in a lake can suffice for a whole season, if done soon enough.

Also, the earlier you catch a bloom, the less it will cost, starting at about $600 per acre with guaranteed success for three months, the company says. If the lake is seriously infected the price can triple or more, as treatment may have to stretch over days. Call too late and the fish and lake bottom—dwellers will all be dead anyway.

Apropos payment, that’s the main reason why the company hasn’t treated any ocean blooms yet. Who’s going to pay? But once financing is allocated, Harel says, they can tackle it, and then other microorganisms will reestablish themselves. He also points out that they can only treat a dead zone if the cause is the cyanobacteria or dinoflagellates. If it’s something else like toxic waste, they can’t help.

Trying to fish in water infected by cyanobacteria
Trying to fish in water infected by cyanobacteriaCredit: REUTERS

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