"If the last blue whale choked to death on the last panda, it would be disastrous but not the end of the world. But if we accidentally poisoned the last two species of ammonia-oxidizers, that would be another matter. It could be happening now and we wouldn't even know..."
--- Microbiologist Tom Curtis in Nature, 2006
Most marine microbes are marine organisms too small to be seen by the unaided human eye (that is, roughly less than 0.1 mm). They make up 98 percent of ocean biomass, are the foundation of all marine food webs, and are a major driver of most of Earth’s biogeochemical cycles, including those of carbon, nitrogen, oxygen, and phosphorus (not to mention those of sulfur, hydrogen, sodium, potassium, magnesium, calcium, and chlorine).