{"id":596826,"date":"2026-04-10T00:54:16","date_gmt":"2026-04-10T00:54:16","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/596826\/"},"modified":"2026-04-10T00:54:16","modified_gmt":"2026-04-10T00:54:16","slug":"how-science-is-rewriting-the-rules-of-marine-taxonomy-one-seaweed-at-a-time","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/596826\/","title":{"rendered":"How science is rewriting the rules of marine taxonomy, one seaweed at a time"},"content":{"rendered":"


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\n By\u00a0
\n Bonnie Radcliffe<\/a>
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\n 9 April 2026
\n 5 min read \n<\/p>\n


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Along the southern coastline, researchers\u00a0dive\u00a0deep to\u00a0collect seaweed from kelp forests and rocky platforms, taking small samples and\u00a0the\u00a0location\u00a0of each sample. Back in the lab, the specimens are preserved\u00a0\u2013\u00a0some dried, others kept alive \u2013 so they can be studied,\u00a0cultured\u00a0and sequenced.\u00a0<\/p>\n

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Much\u00a0of the seaweed lining our beaches,\u00a0which shapes underwater forests and feeds marine life, remains scientifically mysterious. Researchers estimate that as much as half of seaweed species are still unknown to science\u00a0\u2013\u00a0not because\u00a0they\u2019re\u00a0rare, but because many look deceptively similar and were historically grouped together.\u00a0
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\n Dr Cintia Iha is a seaweed taxonomist and research scientist at CSIRO. Image: CSIRO\/Matt Marrison.
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Seaweeds create vital underwater habitats, support marine life, help stabilise coastlines and are becoming important ingredients for new industries.\u00a0Understanding where\u00a0different\u00a0species come from enables researchers to make informed decisions about conservation, how to\u00a0protect\u00a0and preserve\u00a0underwater environments\u00a0and\u00a0monitor\u00a0changes to the environment.\u00a0<\/p>\n

Dr Cintia Iha, seaweed taxonomist\u00a0and research scientist\u00a0at CSIRO, explained that\u00a0identifying\u00a0seaweeds was traditionally done by eye and hand, using features like colour,\u00a0texture\u00a0and\u00a0microscopic sections.\u00a0<\/p>\n

\u201cTaxonomy is the science of\u00a0identifying\u00a0and naming a species, but\u00a0it\u2019s\u00a0also like an art. You make sections, look at cells and structures, and sometimes you can guess a species by its smell or the way it feels,\u201d said Dr Iha.\u00a0<\/p>\n

\u201cSome seaweeds have a\u00a0sweet smell\u00a0\u2013\u00a0for example,\u00a0Undaria\u00a0pinnatifida,\u00a0the seaweed that produces wakame,\u00a0whereas\u00a0others are noticeably pungent like ammonia.\u00a0Those scents, plus the texture and feel\u00a0\u2013\u00a0slimy, brittle,\u00a0rubbery, velvety, even\u00a0crunchy \u2013\u00a0can provide clues\u00a0about what a sample might be.\u201d\u00a0<\/p>\n

Today, that skill is being fused with molecular technology to update and refine the seaweed family tree, changing how new compounds for health, materials and climate solutions are discovered.\u00a0<\/p>\n

A shifting\u00a0methodology\u00a0<\/p>\n

Two seaweeds might look similar, but their DNA can tell\u00a0a very different\u00a0story.\u00a0
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\n A seaweed sample stored at the Australian National Algae Culture Collection. Image: CSIRO\/Andrea Wild.
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As DNA sequencing has advanced, researchers have repeatedly found that one \u2018species\u2019 is\u00a0actually several. Dr Iha recalled an example where a seaweed long thought to be a single species turned out to be four or five\u00a0different species\u00a0once scientists examined its DNA.\u00a0<\/p>\n

\u201cYears ago, identification was often subjective\u00a0\u2013\u00a0\u2018this seaweed looks like that one, so they\u2019re the same\u2019.\u00a0Molecular data gives a more objective view. We can test whether groups are truly the same species, or understand how they differ,\u201d\u00a0explained\u00a0Dr Iha.\u00a0<\/p>\n

But modern technology\u00a0doesn\u2019t\u00a0replace the old rules, nor does it rewrite them.\u00a0<\/p>\n

\u201cAn organism is much more than its DNA. Modern taxonomy brings field skills together with molecular tools.\u00a0That\u2019s\u00a0how we get the complete picture.\u201d\u00a0<\/p>\n

The quiet biodiversity of Australia\u2019s seas\u00a0<\/p>\n

Along Australia\u2019s southern coastline\u00a0\u2013\u00a0especially around the\u00a0Great Southern Reef,\u00a0which stretches around the southern half of the continent\u00a0and Tasmania\u00a0\u2013\u00a0seaweeds have evolved in relative isolation, creating a collection of species found nowhere\u00a0else.\u00a0
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\n The Great Southern Reef, which stretches around the southern half of the continent and Tasmania is home to many endemic species of seaweed.
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\u201cThese coastlines host an old and varied marine environment, shaped by currents, temperature gradients and sheltered micro\u2011habitats,\u201d said Dr Iha.\u00a0<\/p>\n

\u201cThe Great Southern Reef has a mix of cold and milder waters that creates small pockets where\u00a0different species\u00a0can evolve. It really is a hotspot, not just for the number of species, but for how many are unique to this region.\u201d\u00a0<\/p>\n

This diversity comes at a time when the\u00a0expertise\u00a0needed to study it is increasingly rare. Australia has a long tradition of seaweed taxonomy, but many of the specialists who built that foundation have since retired.\u00a0A\u00a0small group of the next generation of taxonomists, including Dr Iha,\u00a0is\u00a0now stepping in to continue the work.\u00a0<\/p>\n

Australia\u2019s living\u00a0algae\u00a0library\u00a0<\/p>\n

Supporting this effort is CSIRO\u2019s\u00a0Australian National Algae Culture Collection<\/a>\u00a0(ANACC)\u00a0\u2013\u00a0a living \u2018library\u2019 of more than 1,000 strains of algae, including\u00a0microscopic algae and seaweeds,\u00a0from across Australia, Antarctica and beyond. Each strain is cared for and\u00a0maintained\u00a0so it can be studied,\u00a0compared\u00a0or used in future research.\u00a0<\/p>\n

\u201cA strain is\u00a0basically a\u00a0living snapshot of what was in the ocean at a certain place and time. Because\u00a0it\u2019s\u00a0still alive, we can study it, compare it with other species, or even use it to help restore ecosystems,\u201d\u00a0Dr Iha\u00a0explained.\u00a0<\/p>\n

Keeping that snapshot alive takes dedication.\u00a0Microalgae\u00a0cultures are regularly renewed on a set schedule \u2013 typically every three to\u00a0six\u00a0weeks\u00a0for faster\u2011growing species and less\u00a0frequently\u00a0for slower\u00a0strains. Technicians transfer each culture into fresh, sterile media and\u00a0maintain\u00a0\u2018parent, child and grandparent\u2019\u00a0lines so there is always a backup if one falters.\u00a0<\/p>\n

\u201cSeaweeds can also grow in cultures.\u00a0Imagine the process of growing plants in pots. What\u00a0we\u2019re\u00a0doing in the living library is\u00a0similar, although obviously a little more complex because it requires sterile seawater and supplying the\u00a0seaweed\u00a0with the correct nutrients.\u201d\u00a0<\/p>\n

Maintaining\u00a0living cultures\u00a0is important.\u00a0One example is\u00a0giant kelp,\u00a0a seaweed\u00a0that can reach 60 meters\u00a0in height\u00a0and\u00a0forms extensive sea forests, which are\u00a0under\u00a0threat\u00a0due to increasing\u00a0seawater temperatures. <\/p>\n

As\u00a0these\u00a0underwater kelp forests decline, researchers are\u00a0preserving reproductive cells which can be kept for years and used to\u00a0support\u00a0restoration projects\u00a0\u2013\u00a0including the ability to select strains that may cope with changing conditions, like warming waters.\u00a0<\/p>\n

\u201cWe\u2019re\u00a0helping safeguard species. If a species like giant kelp were\u00a0ever wiped out from the natural environment, we could use the cells we store to grow new plants.\u00a0It\u2019s\u00a0one way we can help protect seaweed biodiversity.\u201d\u00a0<\/p>\n

Reimagining bioprospecting\u00a0<\/p>\n

Bioprospecting is the process of looking for useful natural compounds in living organisms\u00a0\u2013\u00a0things like oils, gels, pigments and chemicals that could become new medicines,\u00a0foods\u00a0or materials. In seaweeds and\u00a0algae, these compounds can have huge value, but\u00a0finding them\u00a0has\u00a0historically\u00a0taken a lot of time.\u00a0

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\n Dr Anusuya Willis and Dr Cintia Iha are research scientists at the Australian National Algae Culture Collection. Image: CSIRO\/Matt Marrison.
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Scientists would grow a species, extract its different\u00a0compounds\u00a0and then test each one to see if anything promising turned up. It’s careful work which\u00a0can be slow,\u00a0costly\u00a0and often a matter of trial and error.\u00a0<\/p>\n

Dr Iha and her colleagues are working on a way to make this kind of bioprospecting faster and more targeted.<\/p>\n

\u201cInstead of relying on trial and error,\u00a0we study\u00a0the biology of each species in depth\u00a0\u2013\u00a0observing\u00a0its\u00a0molecules, the proteins it makes and the natural chemicals already inside it. Together, these pieces\u00a0provide us with important clues about what the species might be capable of producing.\u201d\u00a0<\/p>\n

This approach could make\u00a0a big difference. Seaweeds already support industries\u00a0\u2013\u00a0from the nori used in sushi to the ingredients that help thicken creams and food products.\u00a0There\u2019s\u00a0also\u00a0growing interest in using algae for things like omega\u20113 oils, new medicines, bioplastics and even supplements that help reduce methane from cattle.\u00a0<\/p>\n

\u201cThere are similar prediction tools for bacteria and fungi, but not for algae.\u00a0That\u2019s\u00a0what makes this work exciting.\u201d\u00a0<\/p>\n

Building\u00a0the family tree\u00a0<\/p>\n

Taxonomy can seem distant from everyday life,\u00a0but\u00a0it\u2019s\u00a0a\u00a0quiet\u00a0foundation for\u00a0marine science. <\/p>\n

When\u00a0researchers\u00a0understand exactly which species\u00a0they\u2019re\u00a0working with, we can protect the right habitats, restore damaged\u00a0ecosystems\u00a0and choose the best seaweeds to grow for food,\u00a0materials\u00a0or other products.\u00a0
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\n Dr Iha’s research combines traditional taxonomy and molecular technology to update and refine the seaweed family tree. Image: CSIRO\/Matt Marrison.
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As Australian scientists revise and refine the seaweed family tree, the benefits ripple outward: better conservation decisions, more effective restoration\u00a0efforts\u00a0and\u00a0the ability to unlock\u00a0useful compounds.\u00a0<\/p>\n

\u00a0\u201cThis is because understanding\u00a0evolutionary relatedness is the best prediction tool we\u00a0have to navigate seaweed diversity.\u201d\u00a0<\/p>\n

\u201cWe\u2019re\u00a0building the foundations for the next generation of ocean solutions. When we know what a species really is, we can finally understand what\u00a0it\u2019s\u00a0capable of,\u201d\u00a0concluded Dr Iha.\u00a0<\/p>\n


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