Oceanography (compound of the Greek words ὠκεανός meaning
"ocean" and γράφω meaning "write"), also known as
oceanology, is the branch of Earth science that studies the ocean. It covers a wide
range of topics, including ecosystem dynamics; ocean currents, waves, and
geophysical fluid dynamics; plate tectonics and the geology of the sea floor;
and fluxes of various chemical substances and physical properties within the
ocean and across its boundaries. These diverse topics reflect multiple
disciplines that oceanographers blend to further knowledge of the world ocean
and understanding of processes within: astronomy, biology, chemistry,
climatology, geography, geology, hydrology, meteorology and physics.
Paleoceanography studies the history of the oceans in the geologic past.
Early history
Humans first acquired knowledge of the waves and currents of
the seas and oceans in pre-historic times. Observations on tides were recorded
by Aristotle and Strabo. Early exploration of the oceans was primarily for
cartography and mainly limited to its surfaces and of the animals that
fishermen brought up in nets, though depth soundings by lead line were taken.
Although Juan Ponce de León in 1513 first identified the
Gulf Stream, and the current was well-known to mariners, Benjamin Franklin made
the first scientific study of it and gave it its name. Franklin measured water
temperatures during several Atlantic crossings and correctly explained the Gulf
Stream's cause. Franklin and Timothy Folger printed the first map of the Gulf
Stream in 1769-1770.
1799 map of the currents in the Atlantic and Indian Oceans,
by James Rennell
(adsbygoogle = window.adsbygoogle || []).push({});
Information on the currents of the Pacific Ocean was
gathered by explorers of the late 18th century, including James Cook and Louis
Antoine de Bougainville. James Rennell wrote the first scientific textbooks on
oceanography, detailing the current flows of the Atlantic and Indian oceans.
During a voyage around the Cape of Good Hope in 1777, he mapped "the banks
and currents at the Lagullas". He was also the first to understand the
nature of the intermittent current near the Isles of Scilly, (now known as
Rennell's Current).
Sir James Clark Ross took the first modern sounding in deep
sea in 1840, and Charles Darwin published a paper on reefs and the formation of
atolls as a result of the Second voyage of HMS Beagle in 1831-6. Robert FitzRoy
published a four-volume report of the Beagle's three voyages. In 1841–1842
Edward Forbes undertook dredging in the Aegean Sea that founded marine ecology.
The first superintendent of the United States Naval
Observatory (1842–1861), Matthew Fontaine Maury devoted his time to the study
of marine meteorology, navigation, and charting prevailing winds and currents.
His 1855 textbook Physical Geography of the Sea was one of the first comprehensive
oceanography studies. Many nations sent oceanographic observations to Maury at
the Naval Observatory, where he and his colleagues evaluated the information
and distributed the results worldwide.
Modern oceanography:
Despite all this, human knowledge of the oceans remained
confined to the topmost few fathoms of the water and a small amount of the
bottom, mainly in shallow areas. Almost nothing was known of the ocean depths.
The Royal Navy's efforts to chart all of the world's coastlines in the mid-19th
century reinforced the vague idea that most of the ocean was very deep,
although little more was known. As exploration ignited both popular and
scientific interest in the polar regions and Africa, so too did the mysteries
of the unexplored oceans.
HMS Challenger undertook the first global marine research
expedition in 1872.
The seminal event in the founding of the modern science of
oceanography was the 1872-76 Challenger expedition. As the first true
oceanographic cruise, this expedition laid the groundwork for an entire
academic and research discipline.In response to a recommendation from the
Royal Society, The British Government announced in 1871 an expedition to
explore world's oceans and conduct appropriate scientific investigation.
Charles Wyville Thompson and Sir John Murray launched the Challenger
expedition. The Challenger, leased from the Royal Navy, was modified for
scientific work and equipped with separate laboratories for natural history and
chemistry. Under the scientific supervision of Thomson, Challenger travelled
nearly 70,000 nautical miles (130,000 km) surveying and exploring. On her
journey circumnavigating the globe, 492 deep sea soundings, 133 bottom
dredges, 151 open water trawls and 263 serial water temperature observations
were taken. Around 4,700 new species of marine life were discovered. The
result was the Report Of The Scientific Results of the Exploring Voyage of
H.M.S. Challenger during the years 1873-76. Murray, who supervised the
publication, described the report as "the greatest advance in the
knowledge of our planet since the celebrated discoveries of the fifteenth and
sixteenth centuries". He went on to found the academic discipline of
oceanography at the University of Edinburgh, which remained the centre for
oceanographic research well into the 20th century. Murray was the first to
study marine trenches and in particular the Mid-Atlantic Ridge, and map the
sedimentary deposits in the oceans. He tried to map out the world's ocean
currents based on salinity and temperature observations, and was the first to
correctly understand the nature of coral reef development.
