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What’s in a CORK?
Submitted by JR Microbe on Sat, 10/22/2011 - 17:52
Sometimes, scientists want to know what’s happening down beneath the seafloor over long periods of time when we’re not there to collect samples. In order to answer those questions, they designed CORKs. Today, I got to talk with Dr. Keir Becker, who has worked with lots of CORKs. He told me all about them!
CORKs are observatories—they are long tubes filled with instruments to help scientists measure, or observe, the ocean floor. They are lowered down into the holes we drill and form a seal at the ocean bottom, just like a cork in a bottle. Inside, there are instruments that will collect data like water temperature and pressure, and take water samples until we go and take them out again. We can also go back to the seafloor with an ROV (a robot vehicle that can be controlled from the ship) and download the data or collect some water samples to study. Here’s a look at what’s inside:
OsmoSamplers: Plain old table salt is what works these pumps! They have a long tube filled with salty water next to another section filled with fresh water. The fresh water moves across a special material called a membrane that the salt can’t cross. As it moves, it pulls water from the seafloor into the super-long but really thin collection tubes. We connect a long train of OsmoSamplers together in order to sample water at all depths in the CORK.
Temperature Loggers: These little instruments are about as big as a magic marker. They measure the temperature and record it in their memory chip so scientists can download it when they pick them up. They go inside the OsmoSamplers so that scientists can compare the temperature to other measurements they take and samples they collect.
Pressure Sensors: Long, thin tubes called umbilicals bring water up from different depths inside the CORK, and these sensors measure the pressure of the water in each section. Scienstists use these pressure measurements to figure out how the water flows through the hole. They can even see pressure changes from the tides way down at the bottom of the sea!
Data logger: This records and stores all of the data from the pressure sensors. The data can be downloaded by an ROV, or can be collected when the CORK is returned.
ROV connectors: These are big connectors that can be plugged in underwater by the claw arm of an ROV to download information from the CORK.
And here's how it all fits together!