A Boring Life

摘要

In the deep oceans, carbonate minerals precipitate slowly, forming the building blocks of limestone or the shells of many marine organisms. Some filamentous bacteria, including photosynthetic autotrophs, can bore deep into these carbonates, but this biological mining process remains a paradox; photosynthesis usually causes carbonates to grow, not dissolve. Garcia-Pichel et al. showed how one type of cyanobacteria-originally isolated from a marine snail shell-was able to bore into chips of calcite (CaCO_3) in laboratory experiments by controlling the saturation state of calcium.