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Source: NIWA – National Institute of Water and Atmospheric Research

Looking for a visually striking coffee table book that’ll really get people talking? NIWA principal scientist Wendy Nelson’s just-published field guide to New Zealand seaweed could be the answer.

Published by Te Papa Press, the book is a great one to flick through. It’s beautifully illustrated with underwater and microscopic photographs, herbarium scans and reproductions of images from one of New Zealand’s foremost botanical artists Nancy Adams. Over 150 genera and 250 New Zealand seaweed species are described.  

Seaweed, or macroalgae, can contain fascinating substance. For example, alginate found in brown seaweed has commercial use in products like dental moulds, paint, fire retardants, welding rods and more. Some people are even brewing beer from seaweed! 

New Zealand has over 1,000 different kinds of seaweed. Coloured green, brown or red, Wendy says the different groups have distinctive pigments, and a range of ways of reproducing 

Seaweed have many uses in the kitchen. Sprinkle it in soups, use it in an omelet or add it to mashed potatoes or fishcakes. You can even use it wet to wrap and bake fish fillets. Wendy says you should only collect your seaweed from places with clean water. 

Believe it or not, seaweed compounds can be found in lots of foods you buy from the supermarket shelves – including chocolate milk, pizzas and microwave meals. That’s because hydrocolloids found in some seaweeds are often used as thickeners and emulsifiers.   

In another interesting fact, New Zealand began harvesting and processing agar (natural jelly or a phycocolloid) from seaweed in the 1940s as part of the war effort. Up until then, the global supply of agar was from Asia. 

Elsewhere, seaweed has some interesting anti-viral and anti-fungal compounds that we’re learning more and more about, says Wendy. 

The beloved macroalgae is under threat from various kinds of pollution, climate variability, temperatures extremes, increased storm frequency and ocean acidification. Wendy says temperature extremes are a particular concern, with kelp forests globally, including in New Zealand, shrinking.