Scientists have warned of a potential “regime shift” in the oceans, as the rapid growth of huge mats of seaweed appears to be driven by global heating and excessive enrichment of waters from farming run-off and other pollutants. On a global scale, we appear to be witnessing a regime shift from a macroalgae-poor ocean to an macroalgae-rich ocean. Hu and his colleagues carried out the research in response to reports of expanding seaweed blooms in the Atlantic and Pacific. The best-known example, the Great Atlantic Sargassum Belt, is visible from space, stretching from the Gulf of Mexico to the mouth of the Congo. The team, who say their study provides the first global picture of algae floating in the world’s oceans, found that seaweed blooms increased in area by 13.4% a year over the period examined.

Source: Irish Examiner January 19, 2026 12:33 UTC