August 19: Bumper-Car Rides

08-19_BoulderTeamWe have picked up the boulder team from Hall Land; they and their rock samples are safely on board and they cleaned up pretty well after a few weeks in the field.  Now they are adjusting to life on the ship – so different from the land camp.  In Washington Land they had relatively low winds and surprisingly warm weather. And when they went to a boulder, they were sure it would stay put while they sampled.  And they sampled tons of boulders (literally).  Every rock is bagged, labeled, categorized, and stored for chemical and isotopic analysis.

08-19_DriftingSeaIceOn the ship we live in constant motion.  Thankfully there is no significant swell, but we bounce our way through the ice.  We cannot go to a site and expect to stay there – the current is about 1 knot (roughly 1 mile per hour) and the ship drifts in the wind. Thicker sea ice and icebergs that extend deeper into the water are carried by subsurface currents and may drift in entirely different directions, making our operation akin to the bumper-car ride at the county fair.

08-19_MulticorerWe try to set the ship up about a mile up current of our preferred sampling site, and hang the gear in the water ready to sample as we drift across. This has worked perfectly sometimes, and other times not so much.  We must assemble the record of sedimentation as a kind of jigsaw puzzle, use different coring devices to sample the shallow sediments (a small “multicorer” that gets 40-50 cm cores with a pristine top) and the deeper sediments (a big piston corer that samples up to 12 meters into the sea floor, but may blow away the top sediments).

It is nearly impossible to put these different cores in the same place.  We are trying to pick large targets of “typical” sedimentation so that even if the cores aren’t from an identical place they can be put together in a logical way.  If something goes wrong, it can take hours to re-position the ship and try again.  Sounds frustrating, but it is normal and the salty seagoing scientists take it in stride.

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