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Geology LibreTexts

1.4: Modern Ocean Science

This page should have a summary of the development of modern oceanography, including

  • Sonar and mapping the sea floor
  • The Deep Sea Drilling Program (later known as Ocean Drilling Program, and International Ocean Drilling Program)
  • US UNOLS vessels
  • Deep Sea Submersibles and Remotely Operated Vehicles
  • Autonomous Underwater Vehicles (AUV's)
  • Satellites
  • International research efforts

People have been exploring the ocean for many of thousands of years. In those first days of explorations, it was for the requirements of daily survival while living near the coast instead of the scientific exploration we see today. It wasn’t until the early 1800’s, that President Jefferson funded the United States Coast survey for ocean exploration (NOAA). In 1872, Challenger Expedition conducts the first oceanic expedition. On this mission, salinity, density, temperature and hundreds of new species were discovered and looked at for the first time (NOAA).

In 1912, with the sinking of the Titanic in the deep seas, prompted the need to develop ways of exploration using acoustics, so objects could be detected before making contact with a ship. This was accelerated during WWI, with both sides devising ways of being able to detect enemy submarines (National Geographic).

Mapping the Ocean Floor

Mapping of the seafloor is typically done by measuring the water depth at a certain point, which was historically done using a "lead line". This process was extremely time consuming and inaccurate. Advanced seafloor mapping became possible in the 1920s due to the advent of underwater sound projectors (called "sonar") (NOAA). The technology was created in order to allow allied ships to combat German U-boats, precursors to modern submarines, by projecting sound through the ocean and measuring amounts of echolocation (OIC). This could give users distance and direction measurements of underwater objects.

After the end of the war, the Coast and Geodetic Survey (which would later become NOAA) turned the military tech down into the depths to allow them to begin mapping the western coast of text Atlantic, producing the first detailed maps of the ocean floor (NOAA). Even with the advance of this technology, mapping the seafloor was still a difficult task, as early sonar systems could only take depth measurements directly below the vessel, making mapping a tiresome process of moving back and forth over the surface and connecting individual data points together.

In the 1970s methods became more accurate and efficient when the US Navy declassified "multi-beam" sonar, which allowed research vessels to make more accurate and larger images of the ocean-floor. This and the increase of computer processing power has allowed researchers to collect large amounts of data and quickly compile them into detailed and accurate maps.

Sources

  1. NOAA, National Oceanic and Atmosphere Administration, oceanexplorer.noaa.gov
  2. OIC, Oceanic Imaging Consultants, oicinc.com/history_sonars.htm
  3. Deep Sea Drilling Project DSDP - http://www.deepseadrilling.org/about.htm
  4. DSDP Glomar Challenger - http://www.iodp.tamu.edu/publicinfo/...hallenger.html
  5. Woods Hole Institution Drilling History - http://www.divediscover.whoi.edu/his.../drilling.html