In the struggle to curb the destructive effect of humanity on Earth, the runaway freight train, scientists are increasingly studying the role our oceans can play.
Teaming up with the industry, scientists at the University of Southern California have discovered an algae lift technique that produces abundant algae, which can provide a high-performance biofuel to help us detach ourselves from fossil fuels.
Many terrestrial biofuels capable of feeding cars, planes, boats, and trucks currently come from mass-produced agricultural crops such as corn, soybeans, and grass. There are several problems with these options, such as the use of limited terrestrial spaces for food, the consumption of massive water, pollution by pesticides and fertilizers, and the invasion of rare biodiversity habitats.
Relying on giant seaweed like algae avoids these problems, but algae biology is also better suited to use it as a biofuel.
Giant algae (Macrocystis pyrifera) can grow at an impressive rate of up to 35 cm per day, under ideal conditions. They constantly form new fronds, which allows the harvest of mature fronds, which can reach 30 meters in length and otherwise would only deteriorate and die without affecting the growth of algae.
Because algae are a protist, rather than a plant, their molecular composition lacks the resistant plant lignin that complicates the process of converting terrestrial crops into fuel. In addition, growing algae also captures carbon dioxide, which in turn raises pH levels and oxygen supply to immediate areas, helping to mitigate the local effects of ocean acidification.
But questions remain about whether we can grow enough algae to feed our future in an environmentally friendly way. However, it is possible that researchers have discovered a way to effectively produce seaweed in bulk, increasing and decreasing the depth of the alga in the water.
“We found that deep-cycled algae grew much faster than the algae control group, producing four times the biomass production,” said environmental scientist Diane Young Kim of the University of Southern California.
By traversing the depth of the algae for a day, the team discovered that it was taking nutrients from the deepest missing waters closer to the surface at night, feeding its additional growth, while still receiving enough access to sunlight at lower depths during the day.
The team found that the algae exposed to greater depths underwent some physiological changes that made them better equipped to cope with the increased pressure. Their tires, the air-filled structures that help algae flowers float closer to the sun, became thicker and filled with fluid.
Researchers built an algae lift off the coast of California with fiberglass and stainless steel, with horizontal beams to be able to “plant” juvenile algae. The entire structure was circulated through the water column using a solar-powered automated winch.
“The good news is that the farming system can be assembled from products marketed without new technology,” explained one of the teams, Marine BioEnergy’s chief engineer Brian Wilcox. “Once implemented, deep-cycle cycling farms could lead to a new way to produce affordable, carbon-free fuel year-round.”
This technique could open up to the cultivation of huge nutrient-poor ocean regions, where algae did not grow normally, which would also allow us to protect the vital carbon sinks of naturally occurring algae forests all making use of brown algae.
The team urged further research in this area, although much remains to be resolved before checking whether this idea is really as good as it seems, including the costs and energy requirements involved in growing, transporting and converting the crop. algae biomass in liquid fuels.
But other scientists, such as Woods Hole Oceanographic Institution biologist Scott Lindell, are also working on the selective breeding of harder, larger algae species that would be even more suitable for use as a biofuel.
“In a world of a warmer, drier future,” Lindell said in 2019, “it will be difficult to find a better resource for biofuels than crop algae that do not require arable land, fresh water, or fossil fuel fertilizers. contrast to modern land crops “.
This research was published in Renewable and sustainable energy reviews.