Trace metals in water: why some algae struggle more than others

Algae act like the grass of underwater worlds, turning sunlight into food for fish and other creatures. But tiny amounts of metals in water can harm them. A new study looked at how different algae types react to these metals. Researchers found that diatoms—algae with silica shells—are easily damaged by metals. Green algae, which have softer walls, handle metals better. Some metals, like mercury and tin compounds, are extra dangerous. Others, such as selenium and nickel, barely bother algae. Freshwater algae dislike cadmium, copper and chromium more than saltwater algae do. But saltwater algae are hit harder by lead.The study also checked pollution levels in the Pearl River Estuary in China. About 40% of spots there had risky amounts of metals for algae. That matters because cleaner algae mean healthier food chains. Scientists hope this data will help set better rules for keeping metals out of water.