Sunday, September 26, 2010


Station 14
37° 41.713’ N, 68° 28.402’ W
04:19 EST
Winds: 19 knots
Sea Surface Temperature: 80°F

The CTD was in the water and we were in the computer lab operating the winch. Kilometers of wire unspooled on a video monitor and data streamed across our computer monitors. At night, against the backdrop of a black sea, Atlantis’ machinery appears to float in empty space. But not tonight. Something was different. Something barely perceptible on the video monitor was moving outside. Something big. I opened the door and walked onto the back deck. The ship’s frame obscured my view. I walked further and turned around. And there they were. Three giants reflected in the water.

There is nothing quite like moonlight on a calm sea. The bright light of a waning gibbous beamed silver ribbons across the waves from the horizon to our ship. It was being chased by a deceptively small but unusually bright companion. Not quite large enough to burn with the nuclear fires of sun, but presently close enough to reflect ample light, this bright “star” was actually the planet Jupiter. Together, these two giants wandered peacefully across the sky, looking over us while another giant wandered beneath us.

If we look beneath the shimmering moonlight, beneath the waves that batter our ship, we find a system of currents as wide as the Atlantic Ocean (which happens to be about as wide as the Moon). The strongest lies at the surface and is known as The Gulf Stream. This mighty current wanders along the North American margin, carrying warm water from the tropics to colder northern latitudes. It is one of the primary reasons why London’s climate is milder than the more southerly New York City. It is also easy to see why this is the case: the sea surface temperature is 80°F today. This is in stark contrast to the frigid bottom-water temperature of 35°F. Clearly, the system of currents that runs through the deep is complicated. The speed, width, depth, and locations of these currents have been observed to vary seasonally. They surely have varied on much longer timescales as well. What is certain, however, is that they carry more than water and heat. Like rivers running through the landscape, currents carry the physical, chemical, and biological fingerprints of their source waters. That is why we chose to study this site. Particle transport associated with ocean currents needs to be untangled before we can understand how our planet works. In addition to radiocarbon, we are measuring the concentrations and isotope ratios of dissolved Oxygen, noble gases, Radium, Thorium, Protactinium, Neodymium, and dissolved lignin—tracers that allow us to compare the abundance of material transported horizontally by various currents to that raining down from above.

Today we leave Line W and move south toward Cape Hatteras for our third and final transect. With a little help from the wanderers below and illumination from the wanderers above, we will continue to read the message bottles of Earth.

No comments:

Post a Comment