New Zealand seaweed expert Dr Wendy Nelson on Wellington's south coast. Photo / Nicola Edmonds
The country's top seaweed scientist tells Kim Knight not to take algae for granted.
Flotsam and jetsam. Stinky and salty. "What's this slimy one?" I ask.
New Zealand's foremost seaweed scientist tightens her eyes just a little. "Silky," she corrects.
Minutes later, Wendy Nelson slaps a sopping wet handful of something on my reporter's notepad. "Look how beautiful that is," she says, separating the feathery red tips. My notes are dissolving before my eyes but this is for science.
"Sometimes you can see it better against a white background," she says. "This is the seaweed that was used as the basis for the agar industry in New Zealand."
It's mid-March and we've driven to Moa Point on Wellington's south coast. Planes still scream overhead, a bunch of volunteers comb the pebbly beach for rubbish and Nelson is in her element. I see seaweed, singular - and she sees "at least" 40 separate species.
New Zealand split from Gondwanaland between 65 million-80 million years ago. We are, to subvert the poet, a whole bunch of islands unto ourselves, with about 1500km of coastline and an extended marine territory about 15 times larger than our land mass. We are home to a lot of seaweed we know about - and even more that we don't.
Nelson puts it more technically:
"In total, about 1000 species of seaweed are known to occur in the New Zealand region, although some of these have still not been formally described and it is very likely that many more new species are yet to be discovered," she writes in the forward to a revised and full-colour edition of New Zealand Seaweeds: An illustrated guide.
Why does seaweed matter?
"I try to be polite about this stuff," says Nelson. "But come on, give us a break! More than half of the oxygen that we breathe, that we are really dependent on, comes from aquatic plants. Seventy per cent of the planet is covered by seawater. Instead of being the nutty fringe - 'Oh how weird, why would you study seaweed?' - Why would you not?"
Nelson is a principal scientist for the marine biology section of the National Institute of Water and Atmosphere and a professor of biological sciences at the University of Auckland. She was born in Dunedin and, as a child, was obsessed with rock pools. She drew pictures of the seaweed she found at the beach, wondering what species it was. In 1968, Morton and Miller's The New Zealand Seashore was released - 600-plus pages of animal and plant ecology.
"I still remember going to Whitcombe and Tombs and buying that book and it being something I just poredover. Finding out names, reading about shores that I had not been to."
The grown-up Nelson wears earrings shaped like whale tails and carries gumboots in the back of her car. She spent the morning prior to this interview examining two species of red algae only recently detected in Lyttelton harbour ("and it's likely there is more - they haven't been reported here before and their presence has made us question a whole of lot of other things") and looking at discoveries made in Fiordland in December, strategising how this work will be written up and what additional data is required.
"And the sample I got from Auckland quarter of an hour before you arrived is really interesting - a red seaweed that grows in huge quantities in Manukau harbour and we still don't have a name for it."
Seaweed research, says Nelson, needs more funding.
"We really lack investment in fundamental biological diversity, the databases, the collections and the underpinning taxonomy - that's really crucial ... Should we be species-driven or habitat-driven? There will never be enough money but let's do it on an evidence-based approach."
I nod and dutifully write all of this down. Of course, what I really want to know is can we eat it? Actually, says Nelson, we already do.
She points me to a recent academic journal article titled "the rise of seaweed gastronomy". It cites archaeological excavations in southern Chile that date human consumption of seaweed back to 14,000BCE. Much more recently, seaweed has been at the forefront of two huge high-end restaurant trends - molecular gastronomy and foraging. Its presence is an umami boost (think dashi, the extract made from Japanese konbu, and a key component of miso soup). In summary, seaweed is far more than sushi.
"The majority of food product use is in things called phycocolloids," says Nelson. "Things like agar and carrageenans and alginates."
Many of those gels, foams and bits of spherical magic that came to fame in Spanish chef Ferran Adria's's El Bulli restaurant were, for example, courtesy of the emulsifying, thickening, gel-forming and encapsulation attributes of different seaweeds, she says.
A little closer to the home kitchen: "If you go down an aisle in a supermarket and you look at all these salad dressings and cheesecakes and things like that ... and also, because of the interest in vegan and vegetarian food, seaweed is replacing gelatin and other animal-based things."
There is a seaweed in New Zealand, she says, that can be used to create a gel that won't melt until it is heated to more than 100 degrees celsius. There is another that is so acidic that when it dries on a rock it leaves an etched outline (scientists routinely get calls about this one from people who think they have found a seaweed fossil).
It is possible to farm seaweed but, Nelson says, "you'd have to really know what it is you were wanting to do, and work backward to your product".
The internet abounds with suggestions that seaweed could save the planet. Nelson has co-authored a paper on the potential of kelp forests in the fight against climate change and the use of seaweeds as biofuels. It has long been recognised as a good source of compost and even (according to a 1937 report in the Nelson Mail) a possible component in the production of boots and furniture.
"We can produce seaweed linoleum, walls, furniture, boots and shoes at half the present cost of those articles," boasted Scottish businessman J.S. Campbell. "My seaweed products are rot-proof, fireproof and sound-proof."
The veracity of his claim is, sadly, lost to history.
In New Zealand, many may remember eating Gregg's Seameal Custard, high in iodine and promoted as a goitre preventative. Nelson says that during World War II the supply of Japanese agar (used mainly by pharmaceutical producers to grow bacteria and fungi cultures) dried up and the local industry came into its own.
Her notes on seaweed as sea vegetables reference the bright green Caulerpa, sometimes called "sea grape" and various species of Ulva, known as sea lettuce, "which can be eaten in soups or stews, or used finely cut". Karengo is the Māori name for nori (the seaweed we know best as a dried sushi wrapper) and Japanese wakame (Undaria) is also found here.
She says if you are harvesting for home consumption, you should research water quality standards - don't collect seaweed from an area where you wouldn't collect shellfish. Also, she stresses, don't forget that seaweed is a natural phenomenonand that while there are sometimes nuisance outbreaks of algae, the large loads that are dumped on beaches by storms have an ecological benefit.
"That stuff that gets washed up is really important for nesting seabirds, as a habitat for a whole variety of things. Some of that stuff is going to be washed back out to sea and be resuspended and it will be broken down and the filter feeders like mussels will be filtering out those little bits of yumminess from the ocean. You can't just go, 'That's slimy and yucky.' It''s just completely ignoring the interconnectedness between land and sea - and our dependence on natural processes."
Down at the beach, Nelson hands me what looks like a blob of mucous. How can that be seaweed, I ask? "I don't understand that question," she says. "It lives in the ocean, it's related to the other brown algae. It belongs to a particular group of sacs and tubes and its closest relatives can be long tubes, like strings of sausages. That's just the way it grows."
Sometimes, she says, this member of the genus Colpomenia can grow to bath-cap size. Turns out, seaweed is not just swishy Durvillaea (which you might call kelp) though if you can see that massive brown algae that Māori used as a storage bag for muttonbirds, then you know for sure you're in the Southern Hemisphere. Turns out seaweed is sometimes a pink rock (covered in corraline algae) or the sculptural dried bit off the end that I have just learned is not a root but a "hold-fast". Also, it's okay to interchange "algae" with "seaweed".
Nelson knows better than anyone what we don't know about seaweed. Last year she was the lead author of a Department of Conservation report that assessed the status of 938 New Zealand macroalgae - 874 of them for the first time. Some 609 were labelled "data deficient" meaning they are very poorly understood. Two seaweeds were assessed as nationally critical, including one which was collected on a single occasion from a now-destroyed wooden wharf at Campbell Island.
Nelson: "It seems there is an invisibility about it. A perception that it's not that exciting."
She has her gumboots on and Cook Strait is lapping at her ankles.
"There's a cast of thousands in there. That's habitat, that's what it's about. Things living cheek-by-jowl ... we don't know what we're losing and what we need to protect. We're very coastal, we're only recently settled in the last 1500 years or so, and if we can't get it right with a small human population in a place of high diversity where the human footprint has been relatively light ... I mean, what hope is there?"
New Zealand Seaweeds: An Illustrated Guide, by Wendy Nelson (Te Papa Press, $65)
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