Making the most of good weather

June 16, 2013

Today we made the most of the good weather. In the morning we launched the remotely operated vehicle (ROV) Doc Ricketts, which descended at 35 meters (115 feet) per minute to make its way to Station M by around breakfast time.

The dive had several missions. The first was to recover deep-sea sponges that are part of a growth-rate study. Last November, collaborator Amanda Kahn used the ROV to put chambers over these sponges and inject dye into the water. We picked up the chambers a few days later, hoping the sponges had taken the dye into their tissues and formed a distinct growth ring that Amanda can trace back to known dates. Today we picked up one of those sponges. We will mail it back to Amanda once we’re back on shore, and she will measure how much the sponge has grown since it was dyed. After picking up the sponges, we put sea cucumbers into the respirometry chambers on the elevator, and then videotaped three kilometers (1.8 miles) of the seafloor. In collaboration with MBARI’s video lab team, we will use this video to identify and count the animals living at Station M. Over time we can use ROV footage to measure changes in diversity and abundance in animal communities.

A low-resolution frame grab from the high-definition video taken by the ROV Doc Ricketts. This marker helped the ROV pilots relocate the exact same sponge that was dyed in November 2012 (the sponge is the white disc at the base of the marker).

A low-resolution frame grab from the high-definition video taken by the ROV Doc Ricketts. This marker helped the ROV pilots relocate the exact same sponge that was dyed in November 2012 (the sponge is the white disc at the base of the marker).

The next objective for today was to redeploy the camera tripod and sediment-trap mooring. While the ROV was in the water, Henry Ruhl and Rich Henthorn were in the control room with the ROV pilots overseeing operations on the bottom. At the same time, the engineers were on deck and in the lab preparing the camera tripod, and I was preparing the sediment traps for deployment this afternoon. We downloaded data, checked software, changed batteries, cleaned O-rings, reprogrammed the equipment, and put cups back on the sediment traps (so they can catch a new batch of sediment every 10 days). By the time the ROV was on deck we were ready to deploy the mooring.

The first sediment trap is redeployed. The entire mooring—floats, lines, and all—is about 800 meters (half a mile) long and takes about two hours to place carefully into the water. Each instrument needs to be staged on deck and deployed in a specific order. The last item to go in the water is the camera tripod (on the right).

The first sediment trap is redeployed. The entire mooring—floats, lines, and all—is about 800 meters (half a mile) long and takes about two hours to place carefully into the water. Each instrument needs to be staged on deck and deployed in a specific order. The last item to go in the water is the camera tripod (on the right).

—Crissy Huffard