Take part in the Big Seaweed Search 2023!
The Natural History Museum is inviting volunteers around the British coastline to take part in an annual survey to record and monitor the distribution and abundance of different species of seaweed.
The Big Seaweed Search is run by the Natural History Museum in partnership with the Marine Conservation Society (MCS). Monitoring our shores is very important, but scientists need more help. That’s where we all come in.
Since 2009 hundreds of volunteers have submitted data from observing and recording what’s happening on our local beaches. This gives researchers vital information needed to monitor the effects of climate change and rising sea temperatures on this crucial marine plant, helping us to manage and conserve our coasts for the future.
What is seaweed?
Seaweed is the common name for a variety of different species of marine plants and algae that grow in the ocean, as well as rivers, lakes and other bodies of water.
There are over 12,000 known species of seaweed around the world, with over 650 species living and growing around the UK (around 7% of the total).
Their colours vary, but are usually broken down into three groups:
- Brown seaweeds: Phaeophyceae
- Red seaweeds: Rhodophyta
- Green seaweeds: Chlorophyta
Generally, they anchor to the bottom of the sea or other solid structures using root-like ‘holdfasts’ and are distributed at different shore levels (upper, middle, lower). Species that have adapted to being out of the water for longer during tidal changes are found further up the shore.
Why do we need seaweed?
Seaweed has existed on our planet for over 200 million years and plays a vital role in our eco system. The marine plants that live out to sea absorb carbon dioxide from the atmosphere. As they die or decay, and drift to the bottom of the ocean, the carbon is locked away. This is known as ‘blue carbon’ or ‘carbon sequestration’. They also create oxygen; in fact, research suggests they create even more oxygen than plants on the land. This is why it is so important for us to monitor seaweed species to understand and manage these vital resources for the future.
Architecturally seaweed provides habitats, including nursery grounds, and is a food source for thousands of creatures, including fish, invertebrates, birds and marine mammals.
It also helps to protect the coast from erosion, providing a barrier against damaging wave and storm action. Around Britain there is as much kelp forest as there is forest on the land. But kelp is disappearing from many parts of the world, or changing its distribution. The consequences for coastal erosion may be very serious.
Last but not least, seaweed has hundreds of uses for humans. It is edible for humans and frequently used in animal feeds and fertilisers; it’s used in medicines and cosmetics, and even toothpaste. But it’s also used to create biofuels, and some scientists have actually begun to extract cellulose from fast growing species to make suitable plastic alternatives.
What is the purpose of this research?
Climate change and the warming of the seas is impacting this crucial biodiversity. Certain species are in decline, and others have been identified as changing their distribution. These ‘indicator species’ are the focus of The Big Seaweed survey.
Recording and monitoring how marine life changes over time gives scientists valuable insight into the effects of environmental changes, helping us fight for the future of our seas.
Gathering data on the range and biodiversity of indicator species helps scientists monitor three major environmental changes:
- Rising sea surface temperatures: evidence suggests that as our sea temperature rises (we have seen a 2C temperature increase over the past 40 years), cold water seaweeds are moving further north, and the reach of warm water seaweeds is expanding.
- Ocean acidification: around half of the carbon dioxide present in the atmosphere is absorbed by the sea. As CO levels rise, the water in our oceans is becoming more acidic, and this may corrode the chalky skeletons of some seaweeds, impacting both their abundance and distribution.
- Increase in the arrival and spread of non-native species to our shores: as non-native species expand, they escape their normal predators, and often outcompete native species for food, light or space.
How do I join the Big Seaweed Search?
Visit the Natural History Museum or the Marine Conservation Society websites for further information. Some areas of the UK are running in-person seaweed searching events, with training available to get you confident in seaweed searching.
If there are no events near you, you can conduct your own Big Seaweed Search. The Big Seaweed Search recording form and free seaweed guide are available for download, with details of the 14 indicator species that form the focus of this survey.
The best time to start is one hour before low tide. You will need to select and mark out a five-metre wide area of the beach, running from the top of the shore down to the sea.
You should only record living species, as washed-up seaweed could have been transported by waves or storms from other areas. So look for an area that contains rocks, sea walls, piers or other structures containing seaweed, nothing whether its growth is dense and band-forming, patchy or sparse.
Sources:
https://www.nhm.ac.uk/take-part/citizen-science/big-seaweed-search.html
https://www.mcsuk.org/what-you-can-do/citizen-science/big-seaweed-search/
https://www.americanoceans.org/facts/seaweed-information-guide/
