A striking phenomenon observed off the coast of the Llyn Peninsula has generated intrigue among local communities, particularly among seasoned walkers and nature enthusiasts. Judith Unsworth, a 78-year-old pensioner who has trekked the coastal paths for over six decades, experienced an unexpected sight during her walk last Saturday.
Unsworth, who owns property in Abersoch, was captivated by the two distinct shades of blue in the sea, marked by a clear line down the centre of the channel between St. Tudwal's West island and the mainland. She shared her observation on social media, inviting fellow walkers to ponder whether they had noticed the unusual water colours, whilst asserting it was not a result of cloud cover since the sky was clear.
“It was a shame there was no one else passing or I would have spoken to them about it; it was an amazing sight,” Unsworth remarked in an interview with North Wales Live. “I personally thought it could be sewage but others don’t think that.”
Unsworth noted that the phenomenon occurred around two hours after high tide, spurring various discussions among social media users. Responses ranged from plausible geological explanations to more humorous observations. Paul Shepherd speculated that the colouring could be due to sand and silt stirred up by strong easterly winds experienced earlier in the week. Similarly, Nick Hine suggested that sediment from the River Soch, flowing out between the island and the mainland, could account for the striking difference in water colour, especially given the unseasonably warm weather.
The conversation continued with Ian Edmondson dismissing the idea that depth or seabed was responsible, suggesting instead that currents and sediment were more likely factors. Marvin Hall echoed this sentiment, highlighting how changing tides disturb the sand, creating similar visual effects in shallow areas.
Adding a lighter note to the discourse was Alan Pierce Jones, who cheekily remarked, “Light blue is for the Chester people. Dark blue is Welsh water.”
To provide some scientific context, Frankie Hobro from Anglesey Sea Zoo weighed in on the phenomenon. He explained that various natural factors can indeed cause distinct colour differences in coastal waters. Hobro noted that the boundary between different substrates—such as lighter sands and darker rocky reefs—can often appear well-defined under optimal conditions, such as calm seas and clear skies. “In perfect conditions with calm seas and clear skies with the sun overhead,” he said, “these natural underwater landscapes prove to be very distinct and beautiful.”
The distinct line of colour observed by Unsworth may be attributed to the layering of clearer water over a lighter substrate, while darker water lies above a rocky bottom slightly further out. Hobro emphasised that this interplay can be accentuated during calm weather, preventing the usual mixing of the waters, which allows for more visible distinctions.
The event highlights not only the natural beauty of the region but also the inquisitive nature of its residents. As Judith Unsworth continues her walks along the scenic coastal paths, the recent experience stands as a testament to the surprises that nature can reveal, prompting ongoing discussions among those who cherish the landscapes of North Wales.
Source: Noah Wire Services