Surge in Nitrogen Has Turned Sargassum into the World’s Largest Harmful Algal Bloom

Scientists have discovered dramatic changes in the chemistry and composition of Sargassum, floating brown seaweed, transforming this vibrant living organism into a toxic “dead zone.” Results suggest that increased nitrogen availability from natural and anthropogenic sources, including sewage, is supporting blooms of Sargassum and turning a critical nursery habitat into harmful algal blooms with catastrophic impacts on coastal ecosystems, economies, and human health. Globally, harmful algal blooms are related to increased nutrient pollution.

Red Algae Thrive Despite Ancestor’s Massive Loss of Genes

You’d think that losing 25 percent of your genes would be a big problem for survival. But not for red algae, including the seaweed used to wrap sushi. An ancestor of red algae lost about a quarter of its genes roughly one billion years ago, but the algae still became dominant in near-shore coastal areas around the world, according to Rutgers University–New Brunswick Professor Debashish Bhattacharya, who co-authored a study in the journal Nature Communications.