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Entries in Stony Brook (2)

Monday
Jan242011

Putting the world's commercial ships to work

The University of Miami’s Peter Ortner calls the Royal Caribbean cruise ship Explorer of the Seas” the world’s most luxurious research vessel”.  That’s because he and his colleagues affixed instrument packages and even built a small lab on the luxury liner.  Why do this?  Well, if you think about it, cruise ships and commercial ships are criss-crossing the oceans all the time.  What an awesome opportunity to collect data!

Commercial shipping lanes of the world - the ultimate scientific transects?

One of the best sorts of data that Peter’s team collects is called ADCP, for Acoustic Doppler Current Profiling.  Its a sonar method of sorts, but not for measuring the distance to the bottom.  Instead, it can tell you the direction and strength of the current (i.e. its vector) at every depth under the ship.  That’s because the speed that sound travels through the water is distorted by current the same way that the speed of sound through air is distorted by speed (you hear this as, for example, the change in pitch when an ambulance goes by). 

ADCP current vectors (black arrows) recorded by a ship and mapped on temperature of the Gulf Stream. You can see how well they match up

By putting a bunch of ADCPs on a bunch of different ships that cruise regular paths, oceanographers can build up a very detailed picture of currents across ocean basins, on a scale that individual oceanographic vessels could never match.  Along the way, they have discovered new features, especially eddies of various sorts in some unexpected places.  An eddy is a circular current, sort of like a gentle cyclone in water; sometimes they form by themselves, but more often they spin off the edge of a current as it passes through another body of water; these are called frontal eddies.  Eddies can go clockwise or anti-clockwise and they can have a warm core or a cold core or a ring-like structure, depending on how they form.  Eddies are important because they profoundly affect the biology within them - either stimulating or dampening productivity.  They can also be really important for weather and climate, because an eddy can take a lot of heat energy from a warm current like, say, the Gulf Stream, and move it somewhere else.  Climate and weather prediction models work much better when eddies are properly accounted for.

What an eddy looks like by ADCP. The ship travels left to right across the top. Red pixels is where water is coming towards you out of the screen, while blue is it going away from you, into the screen

 

ADCP also gives you BIOLOGICAL data. Here, backscatter shows variations in the distribution of plankton as the ship crosses an eddy like the one in the previous figure

The idea of using commercial ships to collect oceanographic data has proven popular and now a UN committee is working on an implementation plan that would see many ships constantly gathering oceanographic data in all the oceans of the world.  That program is called Oceanscope, and when it reaches maturity, Peter’s dream would have become and reality and he can kick back and watch the data roll in.

 

Friday
Jun042010

Doing my bit to help shape the next generation of fish doctors

Off to NY today to participate the AQUAVET courses, which are a collaboration between Cornell and U. Penn vet schools that aims to train veterinary students interested in fish health.  Historically, its been held at the Marine Biological Laboratory in Woods Hole, MA, but this year its in Southampton, Long Island, at the Southampton campus of Stony Brook University (shown below).  Its a terrific course: the students live in dorms for 2-4 weeks while a steady stream of faculty from all sorts of backgrounds cycle through for a couple of days each, to give lectures on their particular areas of expertise.  My part is aquarium health management principles, and how to identify parasites in histological (tissue) sections.  I am excited about the change of venue this year because the School of Marine Sciences at Stony Brook was where I was teaching before I went to work for Georgia Aquarium.  While I am out there, I'll be giving a public lecture on whale sharks; if you're in the Long Island area and are interested in the big spotty sea dogs, I'd love to see you there.