In the fight to slow down the runaway freight train of the destructive impact of humanity on Earth, scientists are increasingly looking at the role our oceans can play.
In collaboration with industry, University of Southern California scientists have discovered a ‘kelphyser’ technique that produces enough seaweed, which could potentially provide a high-yield biofuel to wean us off fossil fuels.
Many biofuels on land that can power cars, planes, ships and trucks are currently sourced from mass production farms such as maize, soybeans and ryegrass. There are several problems with these options, including the use of limited food space for food, large amounts of water, pollution by pesticides and fertilizers, and the disadvantage of rare biodiverse habitats.
The reliance on giant marine algae such as seaweed not only avoids these problems, but the biology of seaweed is also more suitable for use as biofuel.
Giant kelp (Macrocystis pyrifera) can grow at an impressive rate of up to 35 cm (14 inches) per day, in ideal conditions. They are constantly forming new fronds, which harvest the mature pig leaves, which can be 30 meters long and otherwise only deteriorate and die without affecting the kelp’s growth.
Since kelp is a protis, rather than a plant, the molecular composition does not have the solid plant lignin that complicates the process of converting land crops into fuel. In addition, kelp also captures carbon dioxide, which in turn raises pH levels and oxygen supply in the immediate area, helping to reduce the local effects of ocean acidification.
But there are still questions about whether we can cultivate enough seaweed to fuel our future in an environmentally friendly way. Now researchers may have discovered a way to produce kelp effectively by increasing and decreasing the depth of the kelp in the water.
“We found that kelp grew at depth much faster than the control group kelp, which produces four times the production of biomass,” said Diane Young Kim, an environmental scientist at the University of Southern California.
By driving through the depths of the kelp for a day, the team discovers that it is taking nutrients from deeper into the water that are lacking closer to the surface at night, which has fueled the extra growth while still providing enough access to sunlight in shallower depths get during the day.
The team found that the kelp exposed to greater depths experienced physiological changes that better equipped them to cope with the increased pressure. Their pneumatocysts – the air-filled structures that drive kelp leaves closer to the sun – have become thicker and more filled with fluid.
The researchers built a kelp lift off the coast of California from fiberglass and stainless steel, with horizontal beams on which they could “plant” juvenile kelp. The entire structure was driven through the water column using an automatic solar shaft.
“The good news is that the farming system can be assembled from the products without the new technology,” explained one of the team, Marine BioEnergy chief engineer Brian Wilcox. “Once implemented, depth cycling can lead to a new way of producing affordable, carbon-neutral fuel year-round.”
This technique can open up for farming large areas in the nutrient ocean where kelp will not normally grow, enabling us to protect vital carbon shells from natural kelp forests while still using the brown algae.
The team called for further research in this area, as there is still a lot to work out before we can see if this idea is really as good as it sounds, including the costs and energy needs associated with growing, transporting and converting it. the kelp biomass in liquid fuels.
But other scientists, such as the bisexual of the Woods Hole Oceanographic Institution, Scott Lindell, are also working on the selective breeding of harder and larger kelp species that would be even more suitable than biofuels.
“In a warmer and drier world of the future,” Lindell said in 2019, “it will be difficult to find a better resource for biofuels than farmed seaweed that requires no arable land, no fresh water, and no fossil fuel fertilizer. in contrast to modern land crops. ‘
This research was published in Renewable and sustainable energy reviews.