2010 SouthernExpedition

Day 3 – Stressing out a squid
July 11, 2010

1800 hours – On station between Santa Barbara and the Channel Islands
Latitude 34 degrees 16.8274 minutes N
Longitude 120 degrees 03.4910 W

How will global warming affect marine life? Scientists are studying how decreased oxygen combined with an increase in carbon dioxide in the water will affect animals.

Ocean scientists have commonly defined ocean dead zones based on oxygen concentration in the water. However, in a paper published in Science last year, Peter Brewer and Ed Peltzer linked increased carbon dioxide from fossil fuels to the declining oxygen from global warming, showing that both are significant factors in respiration for aerobic marine animals. They argue that increased CO2 concentrations combined with the low oxygen waters will lead an expansion of the trend to ocean dead zones. To gather further data about these limits to marine life, we came to the low-oxygen waters of the Santa Barbara Basin to collect animals and monitor their reactions to controlled changes in their environment.

Peter Walz spent many hours fitting together all the pieces to the CO2 pump system and troubleshooting various issues. When he completes such a project, he takes photos to document the exact setup, making it easier the next time it needs to be replicated.

At a depth of 200 meters, the ROV pilots caught a small squid in a “detritus sampler” (a large clear container) that was hooked up with an intricate CO2-pump-and-pH-monitoring system, handily rigged by Peter Walz. This system allowed the scientists to inject either carbon-dioxide-enriched seawater into the container or sodium sulfite (to take up the available oxygen). Sensors were attached to the closed-loop system to monitor the changing pH, temperature, and oxygen in the container. With the ROV’s high-definition camera trained on the container, we watched as the squid slowed down in its pulsing movements. When the squid seemed to be stressed to the point of lying motionless on the bottom of the container, the pilot would give the entire apparatus a couple of shakes, which seemed to perturb the squid – for a moment. It jerked and swam briefly, then settled back down, evidence of its declining physical resources. When it appeared the squid had no more fight left, the container was opened and the influx of seawater quickly revived the animal, which swam off.

The intricate plumbing system rigged on the ROV’s “swing arm” to pump carbon-dioxide-enriched seawater and sodium sulfite into a canister that would hold an animal, and all the sensors that would monitor the pH, oxygen, and temperature both inside the canister and in the surrounding water.

This experiment was performed twice more—one time with two squids in the chamber at once and another time with one shrimp. The animals all slowed down and appeared stressed as the CO2 was increased. For all these experiments, MBARI postdoctoral fellow Andreas Hofmann was calculating a “respiration index”, which combines oxygen and carbon dioxide levels to come up with one number that will help estimate the physiological limits of deep-sea animals.

Through experiments such as these, scientists are trying to provide quantitative estimates of the impact of global climate change.

—Nancy Barr

Reference: Brewer, P.G. and E.T. Peltzer (2009) Limits to Marine Life, Science, 324: 347-348

Chief scientist Peter Brewer watches the CO2 experiment on the monitors in the ROV control room.
A close-up of the squid after enduring the drop in pH and oxygen within the canister, the result of adding the CO2-enriched seawater and sodium sulfite.
Previous log Next log

Leg 1

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.

Laser Raman spectrometer DORISS2

By bouncing a specially tuned laser beam off of almost any object or substance—solid, liquid, or gas—a laser Raman spectrometer can provide information about that object's chemical composition and molecular structure.

Push cores

A push-core looks like a clear plastic tube with a rubber handle on one end. Just as its name implies, the push core is pushed down into loose sediment using ROV Tiburon's manipulator arm. As the sediment fills up the core, water exits out the top through one-way valves. When the core is pulled up again, these valves close, which (most of the time) keeps the sediment from sliding out of the core tube. When we bring these cores back to the surface, we typically look for living animals and organic material in the sediments.


Vibracoring is a common technique used to obtain samples from water-saturated sediment. These corers work by attaching a motor that induces high frequency vibrations in the core liner that in turn liquefies the sediment directly around the core cutter, enabling it to pass through the sediment with little resistance.

CTD Rosette

A CTD rosette is a cylindrical frame holding a group of plastic water-sampling tubes. Attached to this frame are instruments for measuring water temperature and conductivity (salinity) at various depths. Also attached to the rosette are instruments for measuring parameters such as chlorophyll, nutrients, and particulate matter in the water. As the frame is lowered over the side of a ship, water samples are taken automatically at various depths. Then the frame is raised to the surface again.

 Research Team

Peter Brewer
Senior Scientist, MBARI

Peter has taken part in more than 30 deep-sea cruises, and has served as chief scientist on major expeditions and on more than 90 ROV dives with MBARI ships and vehicles. His research interests include the ocean geochemistry of the greenhouse gases. He has devised novel techniques both for measurement and for extracting the oceanic signatures of global change. At MBARI his current interests include the geochemistry of gas hydrates, and the evolution of the oceanic fossil fuel CO2 signal. He has developed novel techniques for deep ocean laser Raman spectroscopy, and for testing the principles and impacts of deep ocean CO2 injection.

Ed Peltzer
Senior Research Specialist, MBARI

Ed is an ocean chemist who has been with MBARI since 1997. He has been involved in developing instrumentation and analytical techniques to study the composition of gases in gas hydrates and deep-sea vents. He has also collaborated on the development of new instrumentation for the measurement of temperature and pH from an ROV. As the group's project manager, Ed is also responsible for expedition planning and logistics.

Peter Walz
Senior Research Technician, MBARI

Peter has worked as a research technician for a variety of scientists at MBARI. Most recently he has supported the research efforts of Dr. Peter Brewer and his interests in the ocean chemistry of greenhouse gases such as methane and carbon dioxide. Peter assists with the design, testing and deployment of the ocean going science hardware and works closely with the marine operations group to integrate new equipment to work with MBARI's ROV's.

Andreas Hofmann
Postdoctoral Fellow, MBARI

Andreas is a MBARI Postdoctoral Fellow in the Brewer lab. He obtained a PhD in marine biogeochemistry in the Netherlands after his biology undergraduate and bioinformatics graduate studies in Germany. Andreas' specialty is pelagic and benthic biogeochemical modeling with a focus on pH and proton cycling. At MBARI, Andreas is working on the relation between pH and soundspeed, the characterization of marine "dead zones", the development of a sediment model to estimate biogeochemical rates from pore-water methane profiles obtained with the group's deep sea sediment Raman Probe, and on a few other related topics. On this cruise, Andreas will be involved in experiments using the mid-water CO2 and O2 control system and the sediment Raman probe, as well as in various data processing tasks.

Melissa Luna
Summer Intern, MBARI

Melissa is an MBARI 2010 Summer Intern working in the Brewer lab. She is a graduate of College of Charleston in Charleston, South Carolina with a BS in Chemistry. This summer Melissa will be working on using laser Raman techniques to examine hydrogen sulfide and bisulfide signals as a function of pH in marine pore waters in sea floor sediments.

Nancy Barr
Web/Print Project Manager, MBARI

Nancy manages the editing, design, and production of the MBARI annual report and participates in a variety of editorial and communication projects. She also oversees the institute website. Nancy has been to sea with several MBARI research groups, helping them to carefully remove worms from whale bones, annotate video, sift seafloor sediment, and collect and process water samples. For this expedition she will be in charge of the daily reports that will be posted to this website and will assist with other science crew tasks.

Xin Zhang
Seafloor Hydrothermal Activity Laboratory
Key Lab of Marine Geology and Environment
Institute of Oceanology, Chinese Academy of Sciences

Xin Zhang is a former MBARI student of Peter Brewer and Bill Kirkwood. He was involved in the development of a Deep-Sea Raman Probe for the measurement of sediment pore-water geochemistry.

Zeng Zhigang
Director, Seafloor Hydrothermal Activity Laboratory
Key Laboratory of Marine Geology and Environment
Institute of Oceanology, Chinese Academy of Sciences

Zeng Zhigang's research interests are in hydrothermal vents, geochemistry, economic geology, and the exploration of geology and mineral resources. He is on this expedition to learn more about MBARI's tools and methods for study ocean chemistry.