The region’s seaweed-harvesting and culture industry is growing, with an increasing number of businesses licensed to harvest wild aquatic plants along the coast for food, animal feed, fertilizer, skin-care products and other uses.
The ocean surrounding Vancouver Island provides all that is required for seaweed to thrive — ample sunlight and cold, nutrient-rich water. More than 630 species are known to grow along our coast.
Global seaweed production has doubled in the past decade, and many local harvesters and producers are seeking to develop and meet North America’s growing appetite for seaweed products and help fill Asia’s longstanding hunger for clean, uncontaminated sea macroalgae.
Indeed, Victoria and area has more than 70 eateries that serve sushi or Japanese food.
All of this means that if any of us craves temaki, nori, seaweed salad, the slightly chewy bits of seawood found in miso soup, or dulse or kelp crackers, we have options — fresh, dried, local or imported.
Considered a kind of miracle plant, seaweeds actually aren’t plants. Like plants, they produce food through photosynthesis, but they lack a plant’s structures — roots, stems, leaves and specialized multicellular reproductive structures.
Instead, seaweeds are a kind of macroalgae.
The miracle part is they require only seawater and sunlight to grow. They provide habitat for other sea life. They also moderate ocean acidification.
And key to the emerging Blue Economy — which the World Bank defines as “economic growth, social inclusion and the preservation of livelihoods while ensuring environmental sustainability of the oceans and coastal areas” — they absorb and hold carbon. Because of seaweed, the ocean is one of the largest reservoirs of carbon on the planet.
Unappreciated but critical players in this ocean carbon cycle are the marine bacteria that break down seaweed.
Thanks to some of those same microbes, we humans are able to digest wakame and nori, extracting the protein, minerals, vitamins, omega-3 fatty acids and antioxidants found in the seaweed.
A little over a decade ago, scientists found the genes that enable ocean bacteria to degrade the complex carbohydrate known as porphyran, found in cold-water seaweed, in a stool sample collected from a Japanese adult.
Earlier this year, research revealed those genes are more common in our guts than had been thought. Of particular interest to pointy-headed folk, the genes entered our gut microbiome through a process known as lateral gene transfer, horizontal gene transfer or, as Nature Boy prefers, “weird bacteria sex.”
Bacteria swap genes among each other. This nifty trick allow bacteria to adapt quickly to new environments. Bacteria needn’t wait for rare mutations to arise. They can pick up tried-and-true genes from their neighbours to become resistant to antibiotics or exploit new resources — like any seaweed we eat.
During digestion, our gut bacteria break down the dietary fibre, or polysaccharides, found in fruits, vegetables, and grains. The polysaccharides found in seaweed, however, have very different chemical structures than those in our usual land-sourced foods.
And, somehow, genes from the ocean-dwelling Bacteroidetes — a group of bacteria that plays a key role in the microbiome — found their way into our intestines.
When researchers analyzed the bacteria’s ability to degrade seaweed-derived polysaccharides porphyran, laminarin, alginate and carrageenan, they found that genes for processing laminarin were broadly represented in the U.S. population they sampled, with the genes possibly linked to the related ability to process complex sugars found in oats and whole grains. The other seaweed polysaccharides were used by fewer bacterial species and were present less often.
A search of gene databases of gut microbiomes around the world showed the genes for degrading porphyran were enriched in samples from China and Japan, where seaweed has long been enjoyed at the dinner table.
Genes for processing carrageenan, consumed for 2,500 years in China and a common food additive for decades in North America, were also plentiful in samples from China, Japan and here in North America.
The researchers also discovered that the bacteria Firmicutes, which are even more prevalent in the human gut than Bacteroidetes are, also had acquired genes to feed on seaweed polysaccharides.
Firmicutes are known to live in fish intestines, and the closest ancestors of the genes that seem to have jumped into human gut Firmicutes are those found in fish.
Thanks to weird bacteria sex, we have yet another link to the ocean that helps us enjoy the bounty from the ocean around us.
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