Midwater Ecology 2013 Expedition

March 22-28, 2013

In order to document the effects of declining oxygen concentrations on midwater communities, the midwater ecology research group has conducted approximately one remotely operated vehicle (ROV) dive per month, compiling a time series which measures the identity, abundance, and vertical distribution of the constituents of the midwater fauna at specific sites. The results of the time series demonstrate that several species have already been displaced by the expanding oxygen minimum zone (OMZ). OMZs are depths, typically 300 to 1,000 meters below the surface, where oxygen concentrations are already quite low in many parts of the world’s oceans.

The midwater team will be examining the physiological characteristics of midwater animals relative to the expanding OMZ. This research utilizes the midwater respirometry system (MRS), an instrument which gathers oxygen consumption measurements in situ, to gauge the metabolism of animals without subjecting them to the stresses of decompression during transport to the surface. Data provided by the MRS helps to determine the oxygen level at which each species switches from “regulation” to “compensation.” Once these oxygen levels are known for a number of species, the future of how expansion of the OMZ will change the spatial composition of the midwater community can be predicted, as well as the ecological implications of such changes.

In addition, the MBARI research team will be joined by a group of husbandry staff from our sister organization—the Monterey Bay Aquarium. The Monterey Bay Aquarium is interested in the potential for creating an exhibit of deepwater organisms and will be working closely with MBARI on organisms such as jellies and cephalopods.


Examples of bad and good images of the pteropod Clio recurva. In the left image, you can see a great view of the mouth parts (the dark part in between the wings), but the wings are obscured due to movement of the animal in the tank.

Patience and the money shot

If you follow MBARI expedition blogs (and you should!), you’ve surely read a lot about deep-sea species. But how do we define a species? And how can we tell which individuals belong to a given species? Those may seem like simple questions, but in fact, sometimes they are not.
This Vampyroteuthis infernalis is about 20 centimeters (eight inches) long from arm tips to the tip of its mantle.

Finally, a vampire squid (or two)!

For those of you who have been following the midwater lab’s blogs over the last couple of years, you know that one of our target animals is the vampire squid, Vampyroteuthis infernalis.
This "Mystery Mollusc" is related to snails, even though it has no shell. The pink part in the middle of its body is digestive gland and stomach. The oral hood on the left surrounds the mouth and the "tentacles" to the right undulate when it swims.

Let's descend fast to the bottom – wait, no STOP!

Today, our dive site was the deep Midwater Respirometry System (MRS) site again. Each morning we start our dives at 6:30 a.m., which means the ROV pilots are prepping for the dive before 6:00 a.m. This morning, we started descending quickly to a depth of 2,700 meters (8,800 feet).
This image from the ROV control room shows ROV pilot Randy Prickett (left) hooking the Midwater Respirometry System (MRS) onto an attachment point on the ROV. He then slid the MRS off the hanger and backed away from the mooring.

Collecting squids and the oxygen minimum zone

Today we had two dives. The first was for collections. We collected quite a few squids, including two Octopoteuthis deletron, which Alicia Bitondo and Chris Payne will try to keep happy and healthy in the ship’s cold room.
Galiteuthis in the shipboard tank. Photo by Kat Bolstad.

Here's looking at you!

Today we moved to a deeper site in Monterey Canyon (about 2,800 meters or 9,100 feet). First, we collected small shrimp-like animals called mysids with the Midwater Respirometry System (MRS).
The tail is lost in adult Chiroteuthis calyx, as you can see in this image.

Cephalopod day!

Today we started the day by conducting midwater transects. The midwater lab has done this regularly for the last 16 years. The ROV flies at a steady velocity in 10-minute intervals, from 100 meters (325 feet) down to 1,000 meters (3,250 feet).
The trawl was full of midwater animals like arrow worms, jellies, squid, and fish. Photo by Kat Bolstad.

Setting sail

Today we set sail from Moss Landing Harbor at 0800 hours and after a few hours were faced with high winds making remotely operated vehicle operations difficult.