Monterey Bay Aquarium Research Institute

Seafloor Biology Logbook
Day 9: Amazing Isla Tortuga
March 9, 2012

By late afternoon yesterday, we'd made our way about 250 kilometers (155 miles) south from the Delfin Basin, into the Guaymas Basin to the east of the Baja California town of Santa Rosalia. The wind was howling again, and it looked like our dive site near the Baja coast was going to be too rough to launch the ROV in the 25+ knot winds and rising seas. In hopes of hiding from the wind, we headed for Isla Tortuga, a small island toward the middle of the Gulf, about 30 kilometers (18 miles) further southwest. We rounded the island and eased into the leeward side, where the wind was still blowing hard, but the seas were low enough to launch the benthic respirometer system (BRS) and the ROV. We got everything into the water by about 5:00 p.m.

Small sharks swam just above the seafloor; there seemed to be quite a few juveniles among them.

On the bottom, we were delighted to see conditions much clearer and calmer than we'd experienced over the past couple days in the northern basins. It is so much easier and a lot more fun to view the seabed through clear water. The ROV dove to 760 meters (2,500 feet), where the BRS had settled on the bottom, only about 130 meters (425 feet) from the ship. The water was cold (~5 degrees centigrade) and oxygen was very, very low (two micromolar, or less than one percent of surface levels and 10 times lower than the northern basins at the same depth). The bottom was a very soft mud, but had lots of animals. There were various fishes—eelpouts, hagfish, hake, small sharks, and many batfish—a few days ago we'd seen these and tentatively called them monkfish. Both groups are closely related, but we are fairly certain this is a batfish (possibly Dibranchus spongiosa).

During our last visit here we tried to capture a couple of batfish and put them into respiration chambers, but both fish escaped before we could close the chamber lid. The ROV pilots were ready for the chase this time. Seven batfish were caught and placed in seven respiration chambers, with measurements that continued to this afternoon (March 9). We were delighted.

These charismatic batfish were abundant on the deep, muddy seafloor near Isla Tortuga. They move much faster than you'd think.

Hiding behind Isla Tortuga turned out to be a very good idea. The wind hasn’t stopped, gusting to 30+ knots since we arrived here yesterday afternoon. Even still, the lee of the island was smooth enough to allow dive operations, so in addition to the dive we were able to make yesterday afternoon, we could dive in this spot again today.

The ROV was launched this morning about 2.5 kilometers (1.5 miles) from the south edge of Isla Tortuga and reached the bottom at a depth of 1,200 meters (4,000 feet). The core of the oxygen minimum zone (OMZ) is centered near 600 meters (2,000 feet), and below 800 meters (2,600 feet), oxygen levels in the water rise—at 1,200 meters, there was about six micromoles oxygen per liter seawater, about three times more than at 760 meters where the respiration system is located. The higher oxygen may be the reason for the higher densities of animals living just below the OMZ. Even though it is still low, a little more oxygen may make it habitable. Brittle stars were highly abundant at a depth of 1,200 meters, but were also patchy. As the ROV transited up the steep slope, the brittle stars decreased in abundance. Other species were fairly common, including various patches of sea stars, numerous fish, snails, and anemones. For the most part, it was a mud-covered bottom, but we encountered a steep rocky cliff of pillow lava—evidence of an ancient eruption—beautiful pillow-like lava that now has sponges, corals, and other animals growing all over it.

While a large number of fish like this ophidid were observed, brittlestars were very abundant where the oxygen level of the water was relatively high.

The ROV ascended by 2:00 p.m. and at 3:30 p.m. we released the respiration system from the bottom using the acoustic release. After 25 minutes it was on the surface and we are about to bring it back aboard. Once we have it on deck, we'll download the data collected since yesterday, then analyze the oxygen consumption rates of each animal and learn something about how these fish can make a living in this incredibly hypoxic (low oxygen) habitat.

By the time we are downloading the data, the Western Flyer will turn towards the south and begin the 24 hour steam to La Paz and the end of the third leg of the 2012 Gulf of California expedition.

—Jim Barry


Previous log Next log

Seafloor Biology
 Equipment

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.

Benthic tool sled

You can see the manipulator arm at the upper left side of the photo and the sample drawer with partitions in the lower left. The drawer is shown open on deck, full of rocks. Normally it is closed when the vehicle is operating and only open when a sample needs to be stowed. The partitions help us keep the rocks in order. The rocks look so much alike, all covered in manganese, it is important to know where each rock came from.

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 the ROV'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.

Benthic respirometer system

Oxygen consumption (a measure of biological activity) of the organisms living in the sediment is measured using a benthic respirometer system (BRS). This instrument is used in situ (in place on the seafloor).

Johnson Flux Chamber System

Measures fluxes of CO2 and methane in terrestrial plant communities.


Suction samplers

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


Sediment scoops

Canvas bags on a T-handle for collecting gravel or other materials that fall out of a push-core.


 Crew

R/V Western Flyer

Ian Young
Master


 

George Gunther
First Mate


 

Matt Noyes
Chief Engineer


 

Andrew McKee
Second Mate


 

Lance Wardle
First Engineer


 

Shaun Summer
Relief First Engineer


 

Olin Jordan
Oiler


 

Craig Heihn
Relief Deckhand


 

Jason Jordan
Relief Deckhand


 

Dan Chamberlain
Electronics Officer


 

Patrick Mitts
Steward


 

ROV Doc Ricketts

Knute Brekke
Chief ROV Pilot


 

Mark Talkovic
Senior ROV Pilot


 

Randy Prickett
Senior ROV Pilot


 

Bryan Schaefer
ROV Pilot/Technician


 

Eric Martin
ROV Pilot/Technician


 

 Research Team

Jim Barry
Chief Scientist
MBARI

Jim Barry is a senior scientist at MBARI whose research program focuses on the effects of climate change on ocean ecosystems. In addition to climate change, his research interests are broad, spanning topics such as the biology and ecology of chemosynthetic biological communities in the deep sea, coupling between upper ocean and seafloor ecosystems in polar and temperate environments, the biology of deep-sea communities, and the biology of submarine canyon communities. Jim has helped inform Congress on ocean acidification, ocean carbon sequestration, and climate change by speaking at congressional hearings, briefings and meetings with congressional members.

Ken Johnson
Senior Scientist
MBARI

Ken's research interests are focused on the development of new analytical methods for chemicals in seawater and application of these tools to studies of chemical cycling throughout the ocean. Over the past 15 years, Ken's Chemical Sensor Program at MBARI has developed a variety of sensors and analyzers that operate in situ to depths of 4,000 meters. These instruments have been used to study processes ranging from the distribution of sulfide in deep-sea hydrothermal vent systems, to nitrate in coastal ponds surrounded by intensive agricultural activities.

Kurt Buck
Senior Research Specialist
MBARI

Kurt Buck specializes in quantitative enumeration, ecology, and imaging of marine protists and bacteria. Upper water-column communities from Antarctic and Arctic sea ice to equatorial regions were his initial focus. He is currently working with deep-sea sediment communities including those from hypoxic zones.

Bob Herlien
Senior Software Engineer
MBARI

Bob Herlien is a senior software engineer at MBARI. He is project manager for the Respirometer Upgrade project, which includes the Benthic Respirometer System (BRS) being deployed on this cruise. He is also principal software designer for that system. His responsibilities on this cruise include configuring the BRS for each deployment and assuring that it's in good working shape.

Linda Kuhnz
Senior Research Technician
MBARI

Linda specializes in the ecology of small animals that live in marine sediments (macrofauna), and larger invertebrates and fishes that live on the seafloor or just above it (megafauna). She conducts habitat characterization studies in benthic (seafloor) ecosystems using underwater video and by collecting deep-sea animals. She hopes to find some new and interesting animals in the unique habitats we are visiting on this cruise.

Chris Lovera
Senior Research Technician
MBARI

Chris supports Jim Barry's Benthic Biology and Ecology, and Free-Ocean CO2 Enrichment research projects. On this expedition, Chris's responsibilities are varied, from collection and curation of invertebrates used in Benthic Respiration System metabolic rate and manipulative oxygen and pH studies, to Geographic Information System work, to operation of the dissolved inorganic carbon analyzer. Chris's recent work focuses on the effects of ocean acidification on invertebrate behavior.

Patrick Whaling
Senior Research Technician
MBARI

Patrick has worked at MBARI since its beginning in the fall of 1987. Prior to his move to MBARI, he spent seventeen years at Duke University Marine Lab investigating heavy metals in the marine environment. He currently works with Jim Barry in the design and construction of sampling gear used on the ROV to collect benthic animals, in addition to processing benthic samples and conducting carbon-hydrogen-oxygen (CHN) analyses.

Josi Taylor
Postdoctoral Fellow
MBARI

Josi is a postdoctoral fellow in Jim Barry's Benthic Biology Group. Josi's research is focused on exploring the effects of global climate change—specifically, ocean acidification and hypoxia—on the deep-sea urchin Strongylocentrotus fragilis. Josi looks for effects of environmental change on urchin physiology, behavior, and population/ community structure. During the Gulf of California expedition, Josi will investigate S. fragilis from 200-1200 meters in the Sea of Cortez to identify differences in this population's age structure, depth distribution, physiology, and behavior, as compared to S. fragilis found in the considerably different conditions of the Monterey Bay Canyon System. Josi hopes to use these comparisons of S. fragilis living in two very distinct climates, to better predict the effects of global climate change on community structure and ecosystem function.

Yossellin Tapia De la O
Graduate Student
Universidad Nacional Autónoma de México
Instituto de Ciencias del Mar y Limnología

Yossellin is working on an ecological study of ophiuroids (brittlestars) associated with bacterial mats of the cold methane seeps in the Sonora Margin of Mexico. This study will contribute information about morphological variations, abundance, biomass, and habitat preferences of the ophiuroids.

Adriana Gaytán-Caballero
Graduate Student
Universidad Nacional Autónoma de México
Instituto de Ciencias del Mar y Limnología

Adriana is a doctoral student at Posgrado en Ciencias del Mar y Limnología, UNAM. Her project looks at the abyssal distribution in the Atlantic Equatorial Belt taking as example the crustacean fauna of the asphalt volcano, Chapopote, in the southern Gulf of Mexico, with emphasis on Alvinocaris muricola and Munidopsis geyeri species.



Last updated: Mar. 13, 2012