The UK Met Office forecasts an "extreme" marine heatwave around parts of the UK later this week, with sea temperatures up to 4 to 5C above average in places and the strongest warmth off the coasts of eastern and southern England. Scientists say the event was fuelled by the heat domes that produced record air temperatures in May and June, on top of long-term ocean warming from human-caused climate change. Shallow waters in the southern North Sea and the English Channel can heat quickly, raising concern that seagrass beds and kelp forests will face heat stress that can reduce growth or cause mass mortality. Researchers warn mass die-offs among some seagrasses, shellfish and other species are possible, while warm-water species such as octopus are becoming more common around south-west England. Prof Matt Frost of the Plymouth Marine Laboratory said rising octopus numbers can displace native species and prey on crabs, lobster and scallops, and Dr Zoe Jacobs at the National Oceanography Centre said temperatures now resemble end-of-August conditions. The Met Office projects marine heatwave conditions may become typical by mid to late century if greenhouse gas emissions are not cut, raising the prospect of more frequent and intense ecological impacts on UK marine habitats and the species that depend on them.
