Acid, alien and hot! Beach visitors to put seaweeds under the spotlight


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Beach visitors are being asked to turn scientist this summer to help understand a bit more about the seaside’s unsung hero – seaweed!

The Marine Conservation Society (MCS) has teamed up with the Natural History Museum on a project to get people out on our shores to help study seaweeds. With their 3D structure and multi-coloured forms, seaweeds create shelter and food for an immense diversity of other marine organisms and also support commercial fisheries. But most people don’t give them a second look, and even consider them a slippery nuisance we could do without!

The Big Seaweed Search, a new citizen science project, will help to map out the distribution of seaweeds around Britain. Seaweed distribution and abundance around our coasts is changing. To investigate why this might be and what’s out there, the Big Seaweed Search will try and establish just what is affecting seaweeds on British coasts.

Miranda Krestovnikoff, TV presenter and diver says: “This is a great way to find out more about our beautiful UK seaweeds, and to help researchers track how they are faring in changing environmental conditions. And anyone can join in. At last, seaweeds will get the attention they deserve!”

The seashores and shallow seas around Britain support over 650 species of seaweed, making them globally significant and an important component of British biodiversity. The study will focus on 14 species, to increase our knowledge of how sea temperature increase, sea level rise, impacts of non-native species and increasing acidity are affecting the distribution of different species of seaweed.

“It’s easy to take them for granted, but seaweeds are fascinating, provide shelter and food for an immense variety of marine wildlife, and are of enormous use to humanity”, says Professor Juliet Brodie, of the Natural History Museum. “People are unaware that our daily lives are affected by seaweeds in many ways, from foods and medicines to buffering the effects of rough seas on our vulnerable coastlines”.

In the Big Seaweed Search, eight species of conspicuous wracks (part of the common names of several species of seaweed) have been selected for the public to record. Many of these will probably be familiar, such as bladder wrack, Fucus vesiculosus, with its bladders resembling bubble-wrap that pop underfoot, and knotted wrack, Ascophyllum nodosum, which produces a single egg-like bladder once a year and can live for an estimated 50-60 years.

The study also hopes to unearth more about non-natives and their impact on British coasts. “One of the most well-known ‘aliens’ listed in the study is wireweed, Sargassum muticum, a brown seaweed that was first recorded on the south coast of England in 1973 and has spread very rapidly since then. Another conspicuous non-native seaweed and a favoured food in Japan, Wakame, Undaria pinnatifida, was first recorded in Britain in 1994 on pontoons but is now starting to colonise rocky shores. These ‘aliens’ are here to stay so we need to learn to live with them,” says Juliet.

Justine Millard, MCS Head of Education and Outreach, says the study will establish whether any of these seaweeds are changing in their range, or becoming more or less widespread.  “Anyone can be a citizen scientist. We’ll provide simple instructions and an identification guide so that everyone can make a valuable contribution to our knowledge of this important and underappreciated group.”

To take part, register at

Photo: Frogfish Photography

Nick and Caroline Robertson-Brown

Nick and Caroline Robertson-Brown

Nick and Caroline Robertson-Brown are a husband and wife team of underwater photographers. Both have degrees in environmental biology from Manchester University, with Caroline also having a masters in animal behaviour. Nick is a fellow of the Royal Photographic Society in underwater wildlife photography and he also has a masters in teaching. They are passionate about marine conservation and hope that their images can inspire people to look after the world's seas and oceans. Their Manchester-based company, Frogfish Photography, offers a wide range of services and advice. They offer tuition with their own tailor made course - the Complete Underwater Photography Award. The modules of the course have been written to complement the corresponding chapters in Nick's own book: Underwater Photography Art and Techniques. They also offer equipment sales and underwater photography trips in the UK and abroad. For more information visit

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