(Encyclopedia) marines, troops that serve on board ships of war or in conjunction with naval operation. A British marine corps was established in 1664, and the need for skilled riflemen aboard? 1865April 27, Mississippi River, nr. Memphis, Tenn.: explosion on steamboat Sultana killed 1,547.See also ShipwrecksHurricaneWorst United States DisastersMine (Encyclopedia) merchant marine: see shipping. (Encyclopedia) marine insurance: see insurance. (Encyclopedia) marine pollution: see water pollution. (Encyclopedia) marine biology, study of ocean plants and animals and their ecological relationships. Marine organisms may be classified (according to their mode of life) as nektonic, planktonic, or? (Encyclopedia) marine engine, machine for the propulsion of watercraft. The earliest marine power plants, reciprocating steam engines, were used almost exclusively until the early 1900s. In later? (Encyclopedia) Mariner space program: see space exploration. (Encyclopedia) Papah?naumoku?kea Marine National Monument, 582,578 sq mi (1,508,870 sq km), in the Pacific Ocean surrounding the NW Hawaiian Islands, c.270 mi (435 km) NW of Oahu; est. 2006 as? (Encyclopedia) Census of Marine Life, an international program (2001?2010) to assess and explain the diversity, distribution, and abundance of living organisms in the oceans. A project involving more?