NOAA Teacher at Sea
Onboard NOAA Ship Ronald H. Brown
October 2 – 24, 2001
Mission: Eastern Pacific Investigation of Climate Processes
Geographical Area: Eastern Pacific
Date: October 17, 2001
Latitude: 10º S
Longitude: 85º W
Air Temp. 19.2º C
Sea Temp. 18.6º C
Sea Wave: 2 – 3 ft.
Swell Wave: 3 – 4 ft.
Visibility: 10 miles
Cloud cover: 5/8
Mooring Retrieval Day
Did you know that glass floats? Well it does when it’s round like a balloon and full of air. Try putting a holiday ornament in a bowl of water. Did you know that glass can be stronger than steel? Well it is. That’s why 80 air filled glass balls, each 17 inches in diameter, were attached to the anchor that was holding the mooring in place at 10S, 85W. They had to be strong enough to withstand the incredible pressure at 4000 m. below the surface. But when an acoustic signal was sent out to the hook that was holding the rope to the anchor, the hook released the anchor to the bottom of the sea and the balls floated to the surface in one big group. That was the first step in retrieving the mooring.
The big deal with getting the mooring on board the ship is that it all weighs so much. Just imagine the thick rope leading from the surface all the way down to the anchor. The rope alone weighs thousands of pounds! All along the rope there are science instruments that have been collecting and storing data about things like current, temperature, and salinity. So when the glass balls floated the bottom end of the rope, it allowed us to pull it in from the bottom up. A small orange boat called a RHIB (rigid hull inflatable boat) was sent out to hook onto the balls and guide them to the ship. They were hoisted onto the deck of the ship using a big winch. Take a look at all the simple machines in the photos! Pulleys, levers, inclined planes, wheels with axels, and so much more. Slowly the rope was brought in and wrapped along a big spool. Each instrument was carefully detached and catalogued. They will be carefully transported back to Dr. Weller’s laboratory in Massachusetts where the information will be studied. The instruments from lower end of the rope came up nice and clean. The instruments that were attached to the middle part of the rope had a few creatures stuck on to them. But the instruments near the surface were covered with crabs and mussels and barnacles! How did they get there? Remember that the food chain often starts off quite small. The barnacles that you see in the photo started off as really tiny “plankton” that drift around until it finds something to attach itself to (like the rope!). Then they start to grow, attracting other sea creatures to feed off of them. In no time at all there is a complete food chain living on and around the buoy.
When most of the rope was onboard the RHIB went back out to secure the mooring. This time I got to ride along! It was thrilling to be in such a little boat so far away from the RON BROWN. Even though the sea wave height was only 3 – 4 feet, the little boat got really knocked around! It was like an amusement park ride! You can see that I’m wearing my safety vest and hardhat and I’m holding on tight! We guided the mooring to the ship and then a big crane took hold of it and lifted it onto the deck. Finally the mooring was on board.
Today was a big day on board the RON BROWN. The mooring that was set out here a year ago was located and retrieved. To the uninitiated that may not sound like the biggest deal, but it really is an unbelievable undertaking that requires a lot of forethought, communication, equipment, and muscle. The safety aspects alone require so much preparation. Fortunately it was a successful retrieval and no one was hurt. Now we get to look forward to cleaning the instruments of all those barnacles!
Science fact: The “glue” by which a barnacle sticks (adheres) to something is one of the strongest adhesives known to man!
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