Monday, May 16, 2011

Mapping the Ocean Floor

13th May 2011

Hello, from the multibeam desk! My name is Shannon and I am an undergraduate student at the College of Charleston in Charleston, SC. This is my fifth cruise participating as a mapping technician. I first got interested in mapping the seafloor during my sophomore year at college, when a professor of mine took me on a two week cruise from Charleston to around Nova Scotia. Learning this tool has been a fantastic opportunity for me, as it allowed me to participate in multiple cruises all over the world. I have been able to travel to Key West, Hawaii, Guam, Indonesia and now Chile and the Southern Ocean all because of learning this tool two years ago.

For those of you who have not had the pleasure to work with multibeam, it is a sonar that sends down beams of sound that hit the seafloor and then reflects back to a receiver on the ship. The acquisition system uses the travel time of sound in water to determine the depth from that “ping”. All these individual pings can then be used to construct a bathymetric map (e.g., topography of the seafloor). While as mappers we do not bring up colorful animals or fossils, we produce colorful maps, which in my opinion, is just as exciting!

As a mapper, one must be able to sit at the computer for long periods of time. On this cruise I am working between 0100 and 1300. I find tiny dots conveying information about the seafloor very interesting, and get so excited when we find new features on the seafloor, or fill in areas that have not been covered during previous cruises. Some find it silly that I can get so enthused by little dots on the screen, but these dots hold the key to so much more information. Multibeam mapping can be used to chart the waters, to discover new features that were thought to not exist before, or to find sunken ships or pipe lines. We can discover information about the seafloor at depths exceeding 8000m! Down here in the Southern Ocean, most of the seafloor that we are mapping has never been mapped before. I am so excited to map new areas of the seafloor while aboard the R/V Nathaniel B. Palmer and to see what questions will arise due to these hundreds of dots on a computer screen.

By: Shannon

Weather: 24F, 17 knots of wind and sunshine!

Shannon shows Kathy through some of the newly acquired multibeam (R. Waller).

Three-dimensional view of the seafloor acquired during the NBP1103 cruise aboard the Nathaniel B. Palmer generated in CARIS HIPS and SIPS 7.0 ©

Sometimes we do let Shannon away from her desk. Here she is helping sort a dredge sample that contained a wealth of corals (R. Waller).

Yesterday we did a Kaston core that collected around 2 ft of sediment and corals from 300m. Here Kais begins to process the sample.

This little Galatheid squat lobster came up in an early morning trawl from 800m! (R.Waller).

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