The best bang for the buck!

July 11, 2013

I have had the good fortune to participate in many expeditions with different groups over my 11 plus years at MBARI. I’ve been to sea with benthic ecologists, molecular biologists, geologists, and chemists, and they have all been amazing experiences that I wouldn’t trade for the world. I will say though, that the Haddock lab cruises are really designed for getting the most bang for the buck! It costs many thousands of dollars to operate the Western Flyer each day we are at sea, so the more science we can pack into each day, the better.

To that end, today we started by launching ROV Doc Ricketts at 7:00 a.m., immediately descending to the seafloor at nearly 3,000 meters. Even on or near the seafloor, there are gelatinous animals of interest to the science team. There are small siphonophores that use tentacles to attach to the seafloor so they can float above the bottom and catch tiny plankton as they sweep by with the current. There are also small jellies that sit on the seafloor!

The little white and pink ball that the arrow points to on the left is the siphonophore Stephalia, attached to the seafloor by a tentacle. On the right, you can see a small red jelly, Ptychogastria that sits on the seafloor.

The little white and pink ball that the arrow points to on the left is the siphonophore Stephalia, attached to the seafloor by a tentacle. On the right, you can see a small red jelly, Ptychogastria that sits on the seafloor.


We then spent the rest of the 12-hour dive ascending slowly, searching for interesting animals. Among some of the most striking animals we saw were: (clockwise from upper left): the lobate ctenophore Bathocyroe, the narcomedusa Aegina, a purple narcomedusa Solmissus, and an undescribed mollusc that we call the Mystery Mollusc because it was unknown what group to put it in when it was first discovered.

We then spent the rest of the 12-hour dive ascending slowly, searching for interesting animals. Among some of the most striking animals we saw were: (clockwise from upper left): the lobate ctenophore Bathocyroe, the narcomedusa Aegina, a purple narcomedusa Solmissus, and an undescribed mollusc that we call the Mystery Mollusc because it was unknown what group to put it in when it was first discovered.

While the ROV was diving in the afternoon, the blue-water divers went for a SCUBA dive to collect shallow animals.

Engineer Olin Jordan holds a line to the RHIB as the crane lowers it over the side. For more on blue-water diving, see yesterday's log.

Engineer Olin Jordan holds a line to the RHIB as the crane lowers it over the side. For more on blue-water diving, see yesterday’s log.

Both the SCUBA divers and the ROV’s collections went very well. Every sampler from the ROV was full when it came up at 7:00 p.m.

We filled 12 detritus samplers (in foreground) and 12 suction sampler buckets (background). Lynne Christianson checks the sample log as the science team quickly takes the animals out of the samplers to put in the dark cold room.

We filled 12 detritus samplers (in foreground) and 12 suction sampler buckets (background). Lynne Christianson checks the sample log as the science team quickly takes the animals out of the samplers to put in the dark cold room.

The day is not over yet! At 7:30 p.m., Meghan Powers and Alexander Jaffe deployed the midwater trawl. This net is sent down closed and a messenger is tripped when it reaches depth to open the net. The net is towed for a few hours and then a second messenger is sent to close the net. Then the net is hauled in. This process will take over three hours, then it typically takes hours to sort the animals in the trawl. There are many animals that can be collected in a trawl that are just too difficult or inefficient to catch with the ROV. Combining use of the ROV with SCUBA divers and the deep midwater trawl ensures that we get a nearly complete view of the diversity in the water column at this site. Today alone, there will probably be over 100 animals preserved or processed for further molecular analysis.

Meghan and Alex deploying the midwater trawl net from the stern of the RV Western Flyer.

Meghan and Alex deploying the midwater trawl net from the stern of the RV Western Flyer.

If all goes well, we’ll be doing all three sampling methods throughout the cruise!

— Susan von Thun