A wide shot of seaweed on the sandy shores of the Scottish Atlantic Coast. In the distance are rolling hills.

Seaweed science

Find out about a study led by Professor Juliet Brodie and the Big Seaweed Search team that was published in 2022
Find out about the Big Seaweed Search

    A study led by Professor Juliet Brodie and the Big Seaweed Search team examined the survey data collected between June 2016 and May 2020, assessing both the scientific value of the findings and the effectiveness of the project’s approach. The study also explored how the results could support future research and identified opportunities to strengthen and expand the next phase of citizen‑science development.

    The Big Seaweed Search: Evaluating a citizen science project for a difficult to identify group of organisms

    Using four years of publicly collected Big Seaweed Search data, this study analysed and mapped the distribution of 14 different seaweeds. Collecting and studying this data over time allows us to spot trends in how our coastlines may be changing in response to environmental factors like sea temperature rise.

    The study also showcased the amazing efforts of Big Seaweed Searchers and allowed us to review progress and make decisions on future project developments.

    A person with long brown hair, wearing a black jacket and blue jeans, is kneeling by a rocky shore and looking at a guide book for identifying seaweed

    Student engaging in the Big Seaweed Search on Rottingdean Beach  |  Image credit: Kate Whitton

    Seaweeds in the UK

    The UK coast is rich in seaweed species. Seaweeds capture carbon, act as nurseries for fish, and support a diverse array of organisms. However, seaweed species are declining or disappearing altogether because of environmental change. Rising CO2 emissions, coastal pressures caused by human population growth, and consumption of finite resources, such as fossil fuels, are increasingly putting seaweeds at risk.

    Monitoring of seaweed distribution and abundance has been inconsistent over time and there is limited data available to track changes. Challenges in accessing remote locations and a lack of professional seaweed scientists makes it difficult to carry out this work nationwide.

    a rocky coastline at Priory Bay, Isle of Wight, with moss-covered boulders in the shallow, calm water during the daytime under a blue sky with white clouds. A wooded area lines the right side of the beach.

    Seaweed made visible by a retreating tide at Seaview, Isle of Wight.  |  Image credit: Chris Hodges

    A group of people participating in a Big Seaweed Search. They are exploring a rocky intertidal zone covered in bright green seaweed, with some individuals standing in shallow pools of water. Green hills are visible in the background under an overcast sky.

    Take part in the Big Seaweed Search

    The Big Seaweed Search asks the public to record their observations of the state and abundance of various species. Whether you live by the sea or only visit every now and again, you can get involved in the Big Seaweed Search! It’s free, fun, and suitable for everyone – you don’t need to be a scientist to get involved.

    Take part today

    How was the study carried out?

    Data collection

    Starting an hour before low tide, participants surveyed a five-metre-wide plot on a UK beach for around one hour and recorded how many of the 14 target seaweed species they spotted there. They then uploaded their findings to a website, along with photographs of the survey location and each species they spotted.

    3 people huddled around a stream of water on a beach looking in depth at some live seaweed. They are surrounded by seaweed. All three are holding clipboards.

    Volunteers participating in a Big Seaweed Search survey  |  Image credit: Billy Barraclough

    Verification

    Each record was validated using the photographs provided as part of the project. Validation included confirmation that the seaweed was attached and alive and that the species had been identified correctly by the search participant.

    A close-up of a person's hand holding a small, reddish-brown piece of seaweed over an open, illustrated seaweed field guide on a beach. The guide contains images and text about non-native species and ocean acidification.

    Volunteers checking a piece of seaweed against a seaweed identification guide  |  Image credit: Natural History Museum London

    What did we discover?

    After verification, 1,007 data records were accepted and have been used in a Red List assessment of British seaweeds. A Red List categorises species according to how endangered or at risk from extinction they are, proving how important this data is.

    Whilst some of the data could not be verified, this still provides the research team with insight into the challenges associated with the methodology design or species identification. This information can allow future work to focus on developing areas of the project to improve data quality and make the project more accessible for participants.

    Read the full scientific paper.

    What did the research find?

    • Data from June 2016 to May 2020 were analysed (378 surveys, 1414 people, 1531 hours)
    • The highest number of surveys were carried out in the Southwest and Celtic Seas regions (43.7%) [Map 1]
    • The seaweed that was most often correctly identified was the common low shore species, Serrated wrack (Fucus serratus, 66%)
    • The least correctly identified species was the invasive species, Wakame (Undaria pinnatifida, 5%) [Graph 1]
    • Calcified crusts and coral weeds were most often recorded as patchy across survey plots
    A bar graph titled 'Graph 1: Correct identifications for each species (%)' showing the percentage of correct identifications for 14 different seaweed species.

    Seaweed identification graph

    Image credit: Natural History Museum London

    Learn more about seaweed

    The potential of seaweed

    Seaweed is something we’re all familiar with from trips to the beach, but its potential as a business opportunity for the aquaculture industry is now emerging.
    An orange lumpsucker fish hiding in some kelp.

    What seaweed can teach us about climate change

    There are over 650 species of seaweed found around the UK and each plays a vital role in supporting the health of our ocean and planet and can tell us key information about the effects of climate change.

    Meet the seaweed types

    There are over 650 species of seaweed found around the UK and we’re on the lookout for 14 of them for The Natural History Museum and Marine Conservation Society's Big Seaweed Search.

    Your seaweed surveys make a difference

    Take part in the Big Seaweed Search