Invisible to the naked eye, kelp spores are released in vast clouds from adult plants and immediately set off on a high-stakes journey. Each one swims using two tiny hair-like appendages called flagella — and they are surprisingly quick. Scaled up to human size, a kelp spore would swim the length of an Olympic swimming pool in the time it takes you to blink.
But speed alone isn’t enough. Spores have only a short window of energy to find the right place to settle. Coastal waters are turbulent and often murky, and the surface they land on can make the difference between success and failure. The ideal home for a kelp spore is a stable rocky reef — like the chalk reefs found in places along the Sussex and Kent coast — where a firm surface allows the spore to attach securely and begin to grow. Unstable, shifting, or sediment-smothered surfaces offer far fewer chances of success.
When a spore does find a promising spot, it doesn’t just stop. Settlement is a carefully choreographed process involving arrival, attachment, and the release of a natural glue that hardens to anchor the spore in place. Only then can the next stage of kelp life begin.
These tiny moments have big consequences. Kelp forests act as ecosystem engineers: they provide habitat and food for marine life, help buffer wave energy and protect coastlines, and play an important role in capturing carbon. Successful spore settlement underpins the ability of kelp forests to recover after storms, heatwaves, and human impacts. Without it, forests thin, fragment, or disappear altogether.
My research focuses on these earliest, most overlooked stages of kelp life — how spores move, how they interact with surfaces, and how changes in water quality can tip the balance between success and failure. By understanding these tiny travellers, we can better understand how kelp forests regenerate — and how we might help them thrive.
Written by guest author, Marianne Glascott, Doctoral Tutor and PhD Researcher at the School of Life Sciences, University of Sussex