There are a variety of methods used to sample water in the deep sea. To collect water that is seeping slowly from the sea floor the geochemists use benthic barrels. The barrels are placed over areas where pore water is expected to be flowing upward. A barrel may be left for a few hours or up to several years. Hopefully, it will fill with the seeping fluid. When the site is revisited, a tube is inserted through an opening in the top of the benthic barrel and the water is pulled into a canister.

There are a variety of benthic barrel designs. The one used on the Conical Seamount chimney is a half dome of PVC (plastic) about 18 inches in diameter and 12 inches tall. It has a funnel sticking out of the top. The funnel is a guide to help direct the sample tube when Jason’s pilot attempts to collect the water. The whole apparatus has an odd, non-scientific appearance, hence the nickname, “party hat.”

The huge, active chimney at Conical Seamount was photographed from every angle. Jason’s pilot was able remove the top of the chimney by applying pressure with the base of Jason’s collecting tray. Pore fluids could be seen rising from the top of the chimney’s broken surface. This was an exciting moment as activity at chimneys has been seen so rarely. The party hat was placed over the cut in hopes of collecting some of the escaping pore fluids. The diameter of the chimney at the break was almost 2 feet. This is an exceptionally large chimney. Patty Fryer believes this chimney was one she saw in 1987. If this is the case, by her calculations, it has grown about 3 meters in the past 16 years.

While waiting for pore fluids to seep into the party hat, we traveled with Jason over a large area of Conical’s summit. The bathymetry was varied including ridges, scarps, rocky fields and areas made smooth by a build up of sediment or mud. When the sea floor is covered with sediments that have fallen from the water above, there are numerous sea cucumber tracks. The sea cucumbers eat organic material in the sediments. When the sea floor is serpentine mud that has flowed up from the mantle, there are no sea cucumber tracks. There is no food for them in the serpentine mud.

After more than 12 hours of exploration, we returned to the giant chimney. Using tools stored on Jason’s collecting tray the pilot was able to use Jason’s manipulators to perform a variety of tests. Water was taken from the party hat, I mean benthic barrel, and the barrel was retrieved for future use. A temperature reading was attempted but the temperature probe was not functioning properly. Several large pieces of the chimney were collected and placed in boxes on the collecting tray. Six push cores were taken in the area around the base of the chimney. Push cores are short tubes, about 12 inches long and 3 inches in diameter that collect samples of sediment and mud with a simple push of Jason’s arm. The geochemists were anxious to get samples of mud so close to an active flow. They will study the chemistry of the pore water while the geologists study the mud.

Jason is back on the surface before dark. The scientists gather their samples and rush for the lab. A piston core is scheduled for 0030 (that’s midnight thirty) so everyone is anxious to get started on the lab work.

Science Summary - Day 20, April 11th

Science Objectives, Day 20:

The twentieth day of the cruise, Apr. 11, is being influenced by rising winds and seas as a tropical storm located south of us moves west-northwest. We hope to spend the bulk of the day doing a Jason2/Medea lowering at a site at the summit of Quaker Seamount. If, however, weather precludes the lowering, we will do a piston core at a small serpentinite mud protrusion site we have nicknamed the “nip,” which lies to the east of Quaker Seamount and perform bathymetry surveys to determine the structural context of Quaker seamount and Shamrock Seamount south of Quaker.

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