Whale poop contains iron that may have helped fertilize past oceans

A recent theory proposes that whales weren’t just predators in the ocean environment: Nutrients that whales excreted may have provided a key fertilizer. Analysis of whale excrement shows significant amounts of bioavailable iron, a vital element that’s often scarce in ocean ecosystems, and nontoxic forms of copper, another essential nutrient. Large populations of whales in past oceans may have helped support marine ecosystems.