Early this month, Margate resident Owen Francomb ventured out with his dog Gertie for a stroll along Kent's scenic Thanet coast, but he had no idea that he would need to be saved from a tide of hazardous sludge. However, French bulldog Gertie started to fear when she started sliding under a heavy layer of rotten seaweed on the beach at Newgate Gap.

She was immobile, Francomb claims. "So, expecting the seaweed to be a foot deep, I scrambled down the slipway and leaped down into the beach, but it came up to my belt. I had a lot of trouble getting through it. He and Gertie had to be pulled out of the foul sludge by another dog walker.

Thanet District Council cleaned more than 1,000 tonnes of seaweed from beaches between Minnis Bay and Broadstairs at a cost of £65,000 in just five weeks starting in the first week of July this year, compared to an estimated average of between 400 and 800 tonnes in a full season.

Residents are accustomed to seaweed blooms since they occur frequently when the weather warms up, according to Amy Cook, founder of the neighborhood organization Rise Up Clean Up Margate, which coordinates frequent beach clean-ups and neighborhood environmental projects. This year, though, the entire town has been overcome by the scent of seaweed, which is unusual.

The suffering is not limited to Margate. Another popular tourist destination affected this summer by an exceptionally high amount of decaying seaweed on its beach is Weymouth in the Dorset county.

Extreme marine heatwaves in the North Sea and other favorable growing conditions have benefited the seaweed this year. Strong winds and exceptionally high tides have also caused abundant seaweed to be beached in the south-east of England. Warming waters cause a spread of warm-water organisms, especially fleshier species like kelp and seagrass.

A macroalgae called seaweed can only grow in seawater. It can release the gas hydrogen sulphide during decomposition, which is toxic to fish and can even be fatal. In humans, it can also lead to respiratory issues and eye irritation.

Dr. Brian Lapointe, a Florida-based researcher, has been examining the connection between wastewater and seaweed blooms like those on the Kent coast since 1973. He claims that the hydrogen sulfide odor is a "real issue" and that "people need to take precautions if they're living in an area with those odors."

He explains that because the gas produces sulphuric acid, "[the gas] can affect the electronics in your home. People have lost electronic items, including air conditioners, all around the Caribbean where Sargassum seaweed has been such an issue.

According to UK government recommendations, "notable discomfort" may be felt by the average person after continuous exposure. Increased intake may result in headaches, bronchial tightness, exhaustion, and dizziness.

Due to the presence of a chalk reef, a marine protection zone, Thanet District Council is unable to remove the decaying seaweed from specific sites. Residents are currently advised to close their windows and avoid exercising outside when the stench is present, especially if their breathing rate increases.

Professor Daniel Franklin, a specialist in environmental science, keeps an eye on the effects of abnormally high nitrogen levels in Poole Harbour. The biggest issue with enormous seaweed accumulations, according to him, is that they could result in significant ecological changes and have an adverse impact on various human activities, like tourism.

Agricultural run-off and sewage discharge both contribute to nutrient enrichment of coastal waters in the Kent area.

According to data given by Surfers Against Sewage, Southern Water has already spilled sewage into the ocean through storm overflows at least 374 times between Herne Bay and Whistable alone in 2023, 181 of those occurrences occurring since the start of May during the peak summer season.

Lifeguards in Broadstairs, where E coli and intestinal enterococci colonies have reached as high as 960 per 100 ml this summer, frequently have to keep swimmers out of the water rather than ensuring their safety.

Internationally, seaweed blooms have been connected to health problems. Inès Léraud, a journalist, wrote a best-selling graphic novel titled Green Algae on the proliferation of green algae along the Brittany coastline, which is thought to be caused by intensive factory farming. This summer saw the release of the book's movie version.

Bryony Carter, a founding member of SOS Whitstable, claims the protest organization has observed "a substantial increase in seaweed over the last three years," adding that if it keeps expanding at the rate we've witnessed, it "may cause issues for swimmers in the future."

In a statement, Southern Water stated that it was "committed to reducing use of storm overflows and working to increase our wastewater treatment storage capacity along with nature-based and engineering solutions to divert rainwater away from the sewer system and back into the environment".

They were unable to produce readings for hydrogen sulfide gas in Kent, nor could Thanet Council.