Sulfate-reducing microorganisms are responsible for the sulfurous odors of salt marshes and mud flats. Much of the hydrogen sulfide will react with metal ions in the water to produce metal sulfides. These metal sulfides, such as ferrous sulfide (FeS), are insoluble and often black or brown, leading to the dark color of sludge.
The largest aircraft used for a scheduled domestic service in the USA that is a DOMESTIC route only, is the Boeing 777, though the most common is a Boeing 757 and 767. Some airlines use larger aircraft on domestic legs on an international flight throughout the USA, which do include the 747, however some airlines don't have a license to carry domestic passengers on those routes.
The Airlander 10 is the world's largest aircraft. It looks something like cross between an overgrown blimp and a very large airplane. In a few weeks, the Airlander 10, the world's largest aircraft, will take off for its first full-fledged commercial test flight in the U.K. The aircraft, designed by Hybrid Air Vehicles, is a 100-yard-long aircraft that was first designed for the U.S. Army in 2009. It can be configured to carry up to 10 tons of cargo or hold up to 48 passengers. The Army eventually passed on it, and it is now being re-conceived for commercial use.