Marine Biologists

Marine biologists started to make their study into a real science around the 19th century with a series of British expeditions. In 1872, the HMS Challenger set sail with scientists Sir Charles Wyville Thomson and Sir John Murray on the most important oceanographic mission of all time. Over four years, they traveled 69,000 miles and cataloged 4,717 new species of marine plants and animals. Many marine scientists view the reports from this expedition as the basis of modern oceanography.

Before this time, marine scientists believed that sea creatures inhabited only shallow waters. They believed that the intense cold, pressure, and darkness below about 1,800 feet could not support life. Then, in the late 1860s, the HMS Lightning and the HMS Porcupine made hauls from below 14,400 feet that contained bizarre new creatures.

Scientists began to build precision equipment for measuring oceanic conditions. Among these were thermometers that could gauge the temperature at any depth, containers that could be closed at a desired depth to collect seawater, and coring instruments used to sample bottom sediments. Scientists also figured out techniques for measuring levels of salt, oxygen, and nutrients right on board ship.

Twentieth-century innovations such as underwater cameras, oxygen tanks, submersible craft, and heavy-duty diving gear that can withstand extremes of cold and pressure have made it possible for marine biologists to observe sea creatures in their natural habitats.