Could plankton magnets reduce oceanic dead zones and help feed the world?

Itai Katz, a physicist at Technion, Israel's Institute of Technology, says he initially came up with the idea for the startup while at home with some friends. Seven years later, having brought on board his friends Shahar Noked (a civil engineer with special forces and construction experience) and Arik Pinto (a mechanical engineer with special forces and sales experience) the concept is beginning to prove its worth. Despite some of the unforeseen complexities they’ve encountered on the way.

“When we started this idea, we thought that there's enormous quantities of plankton out there and we just have to go and grab it. We thought we could just place a net and let the natural ocean currents bring it inside,” reflects Katz.

However, he soon realised that huge quantities of power would be required to extract the plankton using such a method of obstructive filtration, due to the viscosity of water. Undeterred, he decided to look into alternatives.

The first port of call was a local desalination plant, where Katz found out that they removed the plankton and other particulate matter from the seawater by using a coagulant that capitalised on the negative electric charge that these particles naturally carry.

“We said: ‘Great, the plankton is negatively charged. Let's make a system using fibres with a large surface area which is positively charged. And our target, the plankton, is going to stick right to it’. And it worked remarkably well, despite the fact that it's only effective for a very, very short distance of nanometres,” Katz explains.

“This filtering scheme, not based on physical obstruction, circumvents many problems arising from water viscosity, which is very significant at the tiny dimensions of phytoplankton, and permits passage of water through the filter without enormous energetic expenditure,” he adds.

These initial experiments were carried out in a very small scale, in the lab. But not only did they show that the plankton could be extracted from the seawater, but also that it could then be retrieved from their synthesised, positively charged fibres using mechanical means. And they have also validated a downstream processing protocol to remove any heavy metals and sediment using filtration and purification.

Following these initial experiments in the lab, they then scaled up, placing their next filter in a raceway fed by a stream of water pumped in from the Mediterranean. After less than an hour the system’s white fibres were green with phytoplankton, which had been trapped by the electrostatic charge, Pinto recalls.

Geographical scope

Although phytoplankton might not only be a key part of the marine food web, but also help to absorb atmospheric carbon dioxide, blooms of these minute plants can reach excessive densities – in particular in areas that are impacted by anthropogenic eutrophication, as caused by runoff from agricultural fertilisers, for example. In these areas the excessive nutrient levels cause vast blooms of plankton which have a hugely negative effect on marine life.

“The Gulf of Mexico [which suffers from huge algal blooms] is fed by the Mississippi River, which carries all the fertiliser surplus used by corn and crop growers all over the American Midwest. The Baltic Sea is very, very prone to this problem. As is the Northern Adriatic. In fact, any coast that borders an ocean on one side and a heavily populated or heavily farmed region on the other side is similar,” notes Pinto.

“When there's light, the phytoplankton produce oxygen, but during the night they breathe it in and [if there’s excess plankton] the water becomes completely hypoxic and everything dies, they sink to the bottom and they decay. The decay process consumes all the oxygen at a very, very high pace, killing everything on the sea bed too,” adds Katz.

If they can remove a meaningful quantity of this plankton, SeaCrop say that they can help to reduce the size and severity of these dead zones. It’s a view that has garnered the backing of one of Israel’s most respected marine biologists, Prof Amatzia Genin.

“In my view, the planned initiative of SeaCrop will contribute to the mitigation of a major, global environmental problem. I see no adverse effects of the planned operations, on the contrary, depending on the scale of SeaCrop’s operation, severely deteriorated ecosystems may be partially or fully revived,” he wrote in a letter of support.

Key markets

Once they have refined how to trap and harvest the phytoplankton, SeaCrop intend to sell it to a number of markets, starting with aquafeed, but with longer term ambitions to move into pet food and consumer products too.

“The global fish feed market is valued at more than $65 billion, expected to reach $110 billion by 2032. There is accordingly a growing need and market for year-round, cost efficient, high-quality, nutrient-rich aquafeed products. Environmental awareness and concerns over the depletion of wild fish stocks used in traditional fishmeal and fish oil production are strongly shifting the industry toward more sustainable, plant-based, and eco-friendly feed alternatives, such as algae, insect meal, and by-products from agriculture and food processing. Our product is very well suited to the aquafeed market, even in a minimally processed form, thanks to the fact that plankton is what fish eat in the wild,” Pinto explains.

While the suitability of phytoplankton for aquafeeds is not in doubt – and SeaCrop’s trials show that it has a useful nutritional profile with a high protein content – the biggest challenge will be to produce it at volume, and for a price that can compete with existing feed ingredients – be they mainstream commodities such as soy protein concentrate or emerging alternatives that include bioreactor-grown algae.

“The price is the painful part of it. But we believe we have a very unique technology because we are using the natural resources of the ocean,” says Pinto.

As he observes, unlike growing soy, for example, there’s no need to prepare and sow the field, or fertilise and water the plants, which should all be huge advantages.

They will, however need to show that the technology works – both practically and financially – at scale, and they have calculated that they will need to produce at least 11,000 tonnes (dry weight) a year to reach critical mass.

“We believe that our technology is well-suited for providing the product at competitive commodity prices. However, since it requires substantial offshore infrastructure associated with high costs, profitability can only be achieved if these costs are distributed across large production volumes. Therefore, this technology necessitates a rather large-scale operation right from the beginning of the commercial phase,” Pinto explains.

The practical set up

In order to achieve this they envisage capturing the algae by suspending positively charged fibrous curtains between two anchored points, hundreds of metres apart. To avoid damage from storms and large vessels, the tops of these curtains are likely to be around 15 m below the surface of the sea, and stretch down to the 25 or 30 m mark, as the upper layers of the water column tend to be the most productive for phytoplankton, due to the penetration of sunlight.

It’s a fairly low tech idea concept, which is one of its major advantages, although the system would likely require an autonomous device to travel back and forth along the curtain, harvesting the collected plankton and delivering it to a central point.

Challenges to come

Scaling – and doing so in an economical fashion – is SeaCrop’s main long term challenge, but before they do this, they are determined to fine-tune their system, first in the lab and then via an oceanic prototype.

“The R&D process is first in order to make sure that technology is working perfectly. Afterwards the plan is to build the prototype and put it in the ocean, rather than pumping seawater into the lab. This will give us some more experience about the ocean,” says Katz.

“The knowledge is there but, bottom line, you need to make sure that this business makes sense,” adds Pinto.

The startup has so far raised around $140,000 – largely from grants – and plans to raise $2 million to take them to the next level.

“We have recently completed a comprehensive due diligence process with a foodtech incubator, resulting in an investment memo and a term sheet. The round size is projected to be approximately $2 million, but is still open and additional investments are of course welcome,” notes Pinto.

While he admits that there are still some uncertainties to overcome, he emphasises that long-term rewards could be substantial.

“We are here to build a huge project to provide another source of food. Today you have rice, wheat, soybeans… and we want to bring another one [plankton] to the table. It's working, and if we're be able to make it on a large scale, it's a game changer,” Pinto concludes.