Judith Unsworth, a 78-year-old pensioner, recently experienced a remarkable sight during her regular coastal walk on the Llyn Peninsula. Last Saturday, she observed a striking visual phenomenon where the sea displayed two distinct shades of blue, separated by a clear line. The event unfolded shortly after high tide, igniting curiosity among local residents and prompting discussions about the cause.
Having spent over six decades walking the coastal paths, Unsworth found herself captivated by the view between St. Tudwal's West island and the mainland. To share her experience, she posted a photo on social media, inquiring if others had noticed the unusual colour variation. She was quick to clarify, “It wasn't cloud cover as some have suggested as it was perfectly clear,” dispelling the notion that the weather conditions were responsible for the phenomenon.
Local discourse quickly erupted around potential explanations, ranging from environmental factors to humorous conjectures. Some speculated that sand movements and silt suspended in the water were responsible for the change in colour, following strong easterly winds in the days prior. Paul Shepherd shared his thoughts on Facebook, suggesting that recent weather conditions may have stirred the sediment.
Contributors to the discussion, such as Nick Hine and Ian Edmondson, offered additional theories regarding the influence of the river Soch and the role of currents, sediment, and light conditions in creating the distinct underwater boundary. Marvin Hall noted that shifts during low tide can disturb the sandy seabed, which could explain the observed colours.
For deeper insight, Frankie Hobro from Anglesey Sea Zoo provided an expert explanation. He described the observable effect as resulting from the meeting of varying substrates on the seabed, specifically a transition from lighter sandy areas to darker rock formations, often accompanied by sudden changes in depth. He explained that “distinct underwater zones like this are relatively common running parallel to the shoreline here in North Wales,” though not always as visible under normal conditions. Factors such as calm weather and clear skies, as experienced during the sighting, can significantly enhance the visibility of these underwater landscapes.
The phenomenon has not only intrigued Unsworth but also engaged the local community in a lively exploration of the natural world around them. As discussions continue, the event serves as an example of the fascinating interplay of environmental forces that shape coastal experiences.
Source: Noah Wire Services