Kelp is on the way: Swetha Sivakumar, on how to make the most of seaweed

On a trip to California recently, my daughter and I were both knocked down by playful waves at the beach. As we were laughing together, my gaze settled on some seaweed clinging to bare rock nearby, and I found myself wondering: How do they do it? How are they not just surviving but thriving in this harsh environment?

Seaweed are a type of algae, and as such, completely lack root systems. This means they can’t even burrow into a surface as a plant would.
The more I looked into these species, the deeper my respect grew.
Like most algae, seaweed reproduce via spores. These spores settle into cracks in a surface such as rock, and secrete a sticky substance that acts as a glue, helping them stay in place. This anchor point, known as the holdfast, has a grip so strong that the rock may crack further under the force of wind or waves; a fragment may even break off and float away; but the seaweed still holds, floating along with it.
It helps that these algae have a flexible stem, called a stipe, which allows them to absorb external force better and literally bounce back.
How does it deal with all the salinity, in the water and the air?
It turns out, seaweed has a little salt factory running within it that desalinates water by isolating the absorbed sodium in vacuoles within its cells. This keeps the salt from causing dehydration or other corrosive damage. The algae is then free to absorb the nutrients in the water, such as nitrogen, phosphorus and potassium. So skilled has it become at separating these two that it is now used, on a small scale, to absorb and filter out heavy metals from wastewater, thus helping in environmental clean-ups.
In the food processing industry, seaweed is quite prized for its complex polysaccharides such as algin, carrageenan and agar. These substances are viscous and help it retain its moisture amid the heat and salinity. In food factories, the polysaccharides are used as gelling and thickening agents in products such as jellies, cakes, whipped desserts and marshmallows.
Seaweed has evolved ways to combat damage from the extensive exposure to ultraviolet sunlight. Its unique chemical defences include protective pigments, antioxidants and bioactive compounds that are extracted for use in the pharmaceutical and cosmetics industries, particularly in sunscreens, moisturisers and balms.
Something this hardy, of course, also poses a risk.
Seaweed so thrives amid adversity that it can worsen the effects of effluent pollution. Wherever fertiliser runoff raises carbon-dioxide levels in water, for instance, one can expect to see such algae thriving, making it even more difficult for other aquatic life to continue. Sometimes, they grow so abundantly that they even clog up coastlines, necessitating expensive clean-up efforts.
Now for their role on the plate: These hardy algae are packed with vitamins, nutrients and antioxidants. Overall, they have left me so impressed that I have decided to incorporate more seaweed into my diet. Initially, the aroma and texture did not appeal to me, but perhaps that was a matter of getting past preconceived notions of what food should be like, and where it should come from.
Anyone who likes umami foods should have no problem with it. In fact, the Japanese chemist Kikunae Ikeda described and named the flavour “umami” after studying the glutamates in kombu, a type of seaweed, in 1908. He was trying to uncover what made Japan’s dashi stocks so delicious.
I am now determined to use it in more experiments too.
(To reach Swetha Sivakumar with questions or feedback, email [email protected])