MCS: Big Seaweed Search

Our coast is home to an amazing array of seaweeds, which can tell us vital information about our climate. Get involved in the Big Seaweed Search to help monitor the impacts of climate change on our marine environment and the unique species that live there.

The Big Seaweed Search is a community science project from Marine Conservation Society (MCS) run in partnership with the Natural History Museum.

Through it they want to learn more about some of the key seaweed species found in our waters, record where they are and find out how their distribution is changing over time. You can help to collect this vital information.

Why is seaweed important?

Seaweeds play a major role in marine ecosystems and are a vital part in the marine food chain providing nutrients and energy for other animals.

Importantly they also help mitigate the effects of climate change and store blue carbon.

As climate change is affecting our marine environment we are seeing sea temperature increases, sea level rise and ocean acidification. These changes alter the distribution of different seaweed species.

Through the Big Seaweed Survey we are recording the distribution of specific species to help us measure the impact of environmental changes.

Know your seaweed

Some of the most common and best known seaweeds are the brown seaweeds bladder wrack, with distinctive air-filled bladders, and spiral wrack, which often has a spiral twist. Also common and easily identified is kelp, which forms thick strands of leathery brown leaves. Kelps are cold water species found all around the UK (and in many other parts of the world), though in particularly large quantities around the coast of Scotland.

There are over 650 species of seaweed around the UK. But we just need you to help us map the distribution of 14 of them. Your survey data will help us learn more about how these seaweeds are important in preserving the health and diversity of our ocean.

The Big Seaweed Search

It’s easy to take part. The Big Seaweed Search guide explains what you need to do, and provides photos to help you to identify each of the seaweeds we are focussing on. You can complete the simple survey on a mobile, tablet or computer.

The survey can be carried out at any time of year and as an individual or in groups – it’s up to you.

Register to take part and download your guide and recording form at

This blog post was originally published as Big Seaweed Search by Marine Conservation Society.

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