We will be taking sediment samples with a box corer. This is a large box, open on top and bottom, which digs down into the sediment on the ocean floor. A spade then closes on the bottom of the box. Then the box corer is pulled back up onto the boat. The sediment in the box corer is then divided into three different groups which are tested in different ways. We dry some samples and run them on the RaDeCC (picture on water sampling page) like the manganese fiber samples. This lets us know how much radium is on the sediment.

Some of the sediment is packed in plastic petri dishes. These dishes are then placed in a machine called a gamma counter. The gamma counter tests for radium, but a different isotope of radium than the RaDeCC. The gamma counter detects gamma radiation that is given off by the sample. Different elements give off different types of gamma radiation. This is how we can tell what element is in the sample.

Other parts of the sediment are put in a pore water squeezer. A hose connected to the top of the squeezer forces air into the round tank. This builds up the pressure in the tank, and forces the water out the bottom while a filter prevents the sediment from getting out. This ‘pore’ water lands in a beaker beneath the extruder. The pore water can then be tested for radium or nutrients.