The sediment event sensor

June 18, 2013

Today we brought up the sediment event sensor (SES), a recent MBARI invention that collects sediment for a few hours at a time, and then takes a picture of it rather than collecting the sample. The SES takes thousands of pictures over the course of a deployment, and allows us to get a better understanding of the timing of sinking material. It complements the traditional sediment traps at the base of the mooring, which collect for 10 days. From the sediment trap cup samples we can see one 10-day period (cup 17 in the picture below) that may have documented one of the largest sedimentation events in history at Station M. Once we’re finished processing the SES images, we will be able to look at the finer detail in the timing of this event, and possibly relate it to the climate conditions leading up to it.

Sediment trap samples, each represents 10 days of collection.

Sediment trap samples, each represents 10 days of collection.

We also brought up the elevator with Henry Ruhl’s respirometry experiments, measuring the oxygen consumption of sea cucumbers at 4,000 meters (13,000 feet) depth. This took longer than planned. In order to “tell” the elevator to rise to the surface, the remotely operated vehicle (ROV) crew sent an acoustic signal into the water at a specific frequency set to the sensors on the elevator. By tracking the signal they received back from it, the ROV crew could see that its depth wasn’t getting shallower. It was stuck in the mud, so the ROV dove to freethe elevator’s base. Meanwhile, maintenance continued on the Rover and the SES to get them ready for their deployment the next day.

—Crissy Huffard