Hurrah for Marine Sediments!

July 13, 2010

Location: West of the Azores / West Flank of the Mid Atlantic Ridge

Coordinates Lat / Lon: 37* 14.4029'N / 30* 41.7697' W

Air Temp: 22.50*C / 72.5*F

Humidity: 77.7%

Sea Surface Temp (SST): 23.642*C / 72.5*F

Salinity: 35.7 psu

Depth: 2800 m / 2.8 km / 1.74 miles

Hurrah for marine sediments! It was a very successful sampling day on the R/V Knorr. In the gray morning with lightly spitting rain the team completed a gravity core (no breaks!). The horizon was a smudge of gray, blurred by the rain. And the air felt different today. Obviously it feels humid but the air has a distinctly marine-air dampness to it.

The cores were completed in relatively rapid succession. I say "relatively" because coring the ocean floor more than a mile beneath you inevitably takes time. All cores require careful preparation before they are lowered. A gravity core at this depth takes about 1.5 hours from the time it is lowered into the water to the time it is brought back to the ship. We have been getting back 2-3 sections of PVC full of ocean floor sediment that measure about 1.5 m (~5 feet) in length each. The multi core, which samples only the top portion of the seabed, takes about 2 hours to make the trek down to the seafloor and back up with sediment cores. I tell you this so you have a frame of reference to understand how impressive the CDH Long Core actually is.

With a successful CDH long core we get back more than 20 sections of PVC full of ocean sediment, also 1.5m long each. Today we ended up with 22 sections (three were less than 1.5m). The trip down and back up take ~ 3 hrs however the preparation for lowering significantly adds to that time. Look carefully at the image to the right. The long core is visible as a the orange "pipe" extending along the length of the boat visible in this image.

If you missed the animation of WHOI's long coring system watch it here - it's a really nice overview. The scale of this corer is just unreal! Find Bob White and Paul Walczak in the picture at the top of this page. They are moving the super heavy core clamps after the long core has been released into the water.

WHOI's CDH Long core is an exciting development in oceanography. It is a very long core that is driven into the seabed by a piston. It is a type of gravity core. It's terrific because a great deal of sediment, which reflects the history of the ocean and climate, can be gathered at once and kept neatly in chronological order (oldest at the bottom). Click here to see a great image of the R/V Knorr CDH Long core.

More to follow on the long core...

A last note for today's blog. My bunkmate Sarah and I were talking today about how being out on the ocean in a ship this far from a continent shifts one's perspective. The ocean sprawls out before you with seemingly endless stretches of water in all directions. You get the feeling that you are remarkably tiny. I have been thinking a great deal about people throughout human-time who have crossed expansive waters to migrate to new lands, to search for resources, to engage in battle. The sailing ships, the rowing ships, refugee vessels, military, pioneers, canoes, and colonists all facing the wide sea and going forward. Such remarkable spirit, drive, motivation and curiosity they must have had. And here I am, crossing the Atlantic with people passionate about increasing our understanding of our world. And in them I find remarkable spirit, drive, motivation and curiosity.