Monterey Bay Aquarium Research Institute
2012 midwater ecology cruise

Day 5 – Important observations
July 17, 2012

This morning we started our dive at 6:30 and searched for Sergestes similis shrimp for a new series of Midwater Respirometry System (MRS) experiments. We rapidly collected the six samples we needed, and flew the remotely operated vehicle (ROV) to the mooring to hang the MRS. We will recover it in 24 hours. The ROV was back on deck around 10:00 a.m. and the pilots prepared the ROV for a new type of mission: video transects. A transect is a term used in ecology that defines a determined path followed by scientists surveying the occurrence of a phenomenon of interest (e.g., the presence of a certain type of animal on a defined path). In our case, the goal is to quantitatively measure the different forms of life encountered at different depths in the water column (pelagic habitat). We ran transects from a depth of 200 meters (650 feet) down to 1,000 meters (3,280 feet), at intervals of 100 meters. The transects are run for 10 minutes at a constant speed.

Frame grab taken during a transect at 600 meters (2,000 feet).

The Midwater Time Series project has provided us with almost 16 years of distribution data for mesopelagic animals—those living in the ocean at a depth of between 180 meters (600 feet) and 900 meters (3000 feet)—at the Midwater 1 station here in Monterey Bay. This collection of video measurements, merged with environmental data (e.g., oxygen concentration, salinity, and temperature), gives us information about changes in the density of animals over the course of a year or between years, and also changes in their depth distribution over time. For example, we are able to pinpoint when organisms appear that we haven't seen in the bay for quite some time. The siphonophore Praya was commonly seen on our early transects, but had been absent for several years. In the past few years, we've again observed a number of these interesting siphonophores that can grow to be longer than a blue whale.

Our observations help us to determine which organisms are changing their vertical depth distributions in response to changes in the oxygen minimum zone (OMZ), an area of low oxygen between 400 to 800 meters (1,300 to 2,600 feet). As this area expands, oxygen-rich habitat for some organisms is limited to the upper layers of the ocean. In some cases, organisms will move into the euphotic zone, the upper 200 meters (650 feet) of the ocean, and become prey items to animals that inhabit this sunlit layer. The broadening of the OMZ over time could lead to reduced numbers of key pelagic species here in Monterey Bay. Time series are crucial for identifying long-term changes in populations, and in distinguishing anthropogenic (human-caused) effects from natural cycles. Ours is the only mesopelagic time series of its kind in the world.

—Kris Walz and Rob Sherlock

After the transects, we started searching for interesting species and collected Tomopteris worms and an amphipod living on jellyfish. The ROV was back on deck at 6:30 p.m. and, while the scientists took care of the samples, the pilots prepared the ROV for tomorrow, already the last day of this expedition! But the day is not over, tonight we will first launch a third trawl net and, after recovering it, Henk-Jan Hoving will launch his camera system for an overnight midwater observation.

Tomopteris worm.
It was a beautiful glassy day on "Lake Monterey," which ended with an amazing sunset and green flash! (Green flash not captured in photo.)

—Geraldine Fauville

Previous log Next log


Day 6 Day 6
July 18, 2012
Seeing in the dark

Day 5 Day 5
July 17, 2012
Important observations

Day 4 Day 4
July 16, 2012
A squid's diet

Day 3 Day 3
July 15, 2012
Science never sleeps

Day 2 Day 2
July 14, 2012
Searching the deep sea

day one Day 1
July 13, 2012
Our first dive


R/V Western Flyer

The R/V Western Flyer is a small water-plane area twin hull (SWATH) oceanographic research vessel measuring 35.6 meters long and 16.2 meters wide. It was designed and constructed for MBARI to serve as the support vessel for ROV operations. Her missions include the Monterey Bay as well as extended cruises to Hawaii, Gulf of California, and the Pacific Northwest.

ROV Doc Ricketts

ROV Doc Ricketts is MBARI's next generation ROV. The system breaks new ground in providing an integrated unmanned submersible research platform, with many powerful features providing efficient, reliable and precise sampling and data collection in a wide range of missions.

Midwater respirometry system (MRS)

The MRS conducts oxygen consumption rate measurements in situ gauging the metabolism of animals without subjecting them to the stresses of transport to the surface. MRS has been modified to operate in deeper water with an expanded capacity, enabling respiration studies on animals that live deeper than 1,250 meters.

Detritus sampler

Detritus samplers are large plexiglass containers with lids that can be controlled by the pilot of the ROV and gently closed once an organism is trapped inside.


The CTDO is mounted on the ROV and takes in situ measurements of environmental parameters such as conductivity, temperature, depth, and oxygen concentration.

High frequency suction sampler

This sampler acts like a vacuum cleaner sucking up samples and depositing them into one of the 12 buckets.

 Research Team

bruce robison Bruce Robison
Senior Scientist, MBARI

Bruce Robison's research is focused on the biology and ecology of deep-sea animals, particularly those that inhabit the oceanic water column. He pioneered the use of undersea vehicles for these studies and he led the first team of scientists trained as research submersible pilots. At MBARI, his research group has focused on the development of remotely operated vehicles as platforms for deep-sea science.

kim reisenbichler Kim Reisenbichler
Senior Research Technician, MBARI

Kim's general area of interest is the study of midwater and deep sea animals. He has developed many tools and techniques to observe, manipulate, and collect these organisms, and to maintain the animals in the lab.

rob sherlock Rob Sherlock
Senior Research Technician, MBARI

Rob is interested in the ecology of midwater invertebrates. He has worked in the Robison lab and been involved with the Midwater Time Series since he came to MBARI in 1996, identifying and quantifying mesopelagic animals and the changes in that community over time, depth and relative to other physical factors. He is looking forward to more sea-time this year than last!

kris walz Kris Walz
Research Assistant, MBARI

Kris works with the Midwater Ecology group, analyzing ROV video transects between 50 and 1,000 meters in depth to identify biological organisms from all taxonomic levels, most of which spend their entire lives in the oceanic water column. Kris started working at MBARI in 1996 after finishing her Master's at UC Santa Cruz. She's looking forward to returning to sea this month to collect video transects and search for deep-sea lobster larvae from the family Polychelidae.

susan von thun Susan von Thun
Research Technician, MBARI

Susan works in the MBARI video lab, where her primary responsibility is to watch video taken with MBARI's remotely operated vehicles (ROVs) and make observations about the organisms, behaviors, equipment, and geological features that she sees. While annotating video, she's become adept at identifying numerous deep-sea organisms, specializing in midwater organisms. She works closely with the midwater ecology group and the bioluminescence lab to expand her knowledge of the fish, jellies, cephalopods, and other groups in the midwater.

henk-jan hoving Henk-Jan Hoving
Postdoctoral Fellow, MBARI

Henk-Jan is a postdoc in the Midwater Ecology Group of Bruce Robison, Ph.D., investigating the life history strategies of pelagic cephalopods. Cephalopods have one reproductive cycle after which they die. Henk-Jan is interested in how long deep-sea cephalopods live, and how different species shape their reproductive strategies to optimize their single reproductive event.

Karen Osborn Karen Osborn
Smithsonian Institution

After completing her Ph.D. at University of California, Berkeley and MBARI, then a postdoc at Scripps Institution of Oceanography, Karen received a scientist position at the Smithsonian National Museum of Natural History. Her research focuses on the evolution of pelagic invertebrates, primarily polychaete worms and isopod crustaceans.

Bret Grasse
Monterey Bay Aquarium

Bret is an aquarist at Monterey Bay Aquarium where his job is to highlight and display a wide variety of marine organisms by providing the best possible conditions for each individual in captivity. Bret specializes in tropical systems and cephalopods.

Geraldine Fauville Geraldine Fauville
Summer Intern, MBARI

Geraldine has a master's degree in marine biology and is currently working toward a master's in education, communication and new technologies at the University of Gothenburg. She is a summer intern with MBARI's ITD division, investigating the potential for outreach and communication that social media holds.