Beneath the beauty of the San Francisco Bay, a silent toxin has infiltrated the complex ecosystem: mercury. Mercury’s effects are everywhere in the food chain. The toxin has detrimental impacts across the entire ecosystem, from marine life to land animals. A study by the San Francisco Estuary’s Regional Monitoring Program found high mercury concentrations in the South Bay caused lowered hatchability in the eggs of double-crested cormorants and Forster’s terns.